Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1995-1999  (161)
  • 1990-1994
  • 1997  (161)
  • crystal structure  (134)
  • Atomic, Molecular and Optical Physics
  • Computational Chemistry and Molecular Modeling
  • Nuclear reactions
Source
Material
Years
  • 1995-1999  (161)
  • 1990-1994
Year
Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Reactions of the Dirhenium(II) Complexes Re2 X 4(μ-dppm)2 (X=Cl, Br; dppm=Ph2PCH2PPh2) with Isocyanides. Part XV: A Fifth Structural Isomer of the [Re2Cl3(μ-dppm)2(CO)(CNXyl)2]+ Cation (Xyl = 2, 6-Dimethylphenyl) (1997)
    Springer
    Journal of cluster science 8 (1997), S. 547-551 
    Details
    ISSN: 1572-8862
    Keywords: Rhenium ; dirhenium complexes ; rhenium–rhenium multiple bonds ; isocyanide ligands ; carbonyl ligand ; structural isomers ; crystal structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The reaction of the unsymmetrical, coordinatively unsaturated dirhenium(II) complex [(XylNC)(OC)CIRe(μ-dppm)2ReCl2]O3SCF3 (dppm = Ph2PCH2PPh2) with one equivalent of XylNC in CH2Cl2 affords a fifth structural isomer of the [Re2Cl3(μ-dppm)2(CO)(CNXyl)2] + cation; this is believed to have a CO-bridged structure of the type [(XylNC)ClRe(μ-Cl)(μ-CO)(μ-dppm)2ReCl(CNXyl)]+. The latter complex reacts with a further equivalent of XylNC in the presence of Tl+ to form the [Re2Cl2(μ-dppm)2(CO)(CNXyl)3]2+ cation, which has been shown by IR spectroscopy, and by the X-ray crystallographic characterization of its neutral congener Re2Cl2(μ-dppm)2(CO)(CNXyl)3, to contain a very weak and unsymmetrical CO bridge.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022609214775
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Thermal latent coordination compounds (1997)
    Springer
    Journal of thermal analysis and calorimetry 50 (1997), S. 569-586 
    Details
    ISSN: 1572-8943
    Keywords: crystal structure ; metal(II) picolinate and quinaldinate ; thermal degradation of imidazole and pyrazole complexes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Complexes of the type M(Pa)2(HAz)2 and M(QA)2(HAz)2 (M=cobalt(II) and nickel(II); HPa=picolinic acid, HQa=quinaldic acid; HAz=azoles like imidazole (Him), pyrazole (HPz), benzimidazole (HBzIm) etc.) show a similar thermal behaviour. In the first step of decomposition the corresponding azolinium picolinates or quinaldinates (H2AzPa, H2AzQa) are split off with formation of polymeric mixed ligand complexes M(Pa)(Az) or M(Qa)(Az). X-ray analysis of Co(Qa)2(HBzIm)2 XIIIa illustrates a proton transfer and a subsequent thermal removal of benzimidazolinium quinaldinate (H2BzImQa): Hydrogen bridges from pyrrole nitrogen of the benzimidazole to the non-coordinated oxygen of the quinaldinate predetermine the thermal initiated proton transfer. The high volatility of the heterocyclic acids and the nitrogen coordination are responsible for the formation of the mixed ligand complex Co(Qa)(BzIm) XIVa. Exceptions are the complexes M(Pa)2(HPz)2 XIa-b and M(Qa)2(HIm)2 XVIIa-b. Pyrazole is eliminated from the complexes XIa-b with formation of the solvent-free inner complex M(Pa)2 XIIa-b. From compounds XVIIIa-b quinaldic acid or their decomposition products are split off and a high temperature modification of M(Im)2 XVIIIa-b is formed at elevated temperature. XVIIIa-b are decomposed to the cyanides M(CN)2 similarly to the thermal behaviour of Cu(Im). In the first step the thermal degradation of imidazole and pyrazole adducts of copper(II) picolinates and quinaldinates is characterized by the elimination of azoles. The reason for this thermal behaviour is the weaker coordination of the azole heterocycles in copper chelate compounds.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01979029
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Synthesis and Characterization of the Isocyanide Ligated Centered Zirconium Halide Cluster [(Zr6Be)Cl12(CNXyl)6] (1997)
    Springer
    Journal of cluster science 8 (1997), S. 521-531 
    Details
    ISSN: 1572-8862
    Keywords: Zirconium clusters ; isocyanide ; synthesis ; crystal structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The first isocyanide ligated hexanuclear zirconium halide cluster is reported. The unoxidized [(Zr6Be)Cl12(CNXyl)6] (CNXyl = 2,6-dimethylphenyl isocyanide) was obtained from the solid state precursor K3Zr6Cl15Be by dissolution in CH3CN in the presence of CNXyl. The CNXyl ligands occupy all the axial positions on the cluster. The compound was recrystallized from CH2Cl2 and Et2O. [(Zr6Be)Cl12(CNXyl)6].2CH2Cl2 crystallizes in the space group $${\text{P}}\overline {\text{1}} $$ (#2) with a = 12.092(5) Å, b=12.728(5) Å, c = 14.102(8) Å, α = 104.98(4)°, β =107.11°, γ = 100.94°, V = 1919(2) Å3, Z = l, R = 11.3% and R W = 27.0%. For the bound isocyanide ligands, v CN increases to 2140 cm−1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022605113866
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    The molecular complex of dibenz[a,c]anthracene and trinitrobenzene (1997)
    Springer
    Structural chemistry 8 (1997), S. 141-147 
    Details
    ISSN: 1572-9001
    Keywords: Dibenzanthracene ; trinitrobenzene complex ; trinitrobenzene complex ; π-complex ; crystal structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The crystal structure of the complex between the polycyclic aromatic hydrocarbon di-benz[a,c]anthracene and 1,3,5-trinitrobenzene is reported. The crystals are triclinic, space group P¯1 with unit cell dimensionsa=7.277(2) å,b=11.237(6) å, andc=13.902(5) å,α= 104.13(4)
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02262849
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Structures and tautomeric interconversions of anthraquinone imine derivatives (1997)
    Springer
    Structural chemistry 8 (1997), S. 197-204 
    Details
    ISSN: 1572-9001
    Keywords: Tautomerism ; anthraquinone ; crystal structure ; semiempirical computations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Substituted 1-hydroxy-9,10-anthraquinone-9-imines have been found to exhibit tautomeric interconversions between the 9,10- and 1,10-quinonoid forms in the solid state as well as in solution. Single-crystal X-ray crystallography was used to study the structures of 4-(N-acetyl-p-tolylamino)-9-amino-1,10-anthracenedione and 4-hydroxy-1-phenylamino-10-mesitylimino-9(10H)-anthracenone at ambient and low temperatures. The former compound gave crystals belonging to the monoclinic space group P2l/c and, at 295 K,a=9.684(2),b=16.371(3),c=12.097(2) å,Β=110.41(1)
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02263507
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Synthesis and structure of 5-methoxy-4-methylbenzopsoralen (1997)
    Springer
    Structural chemistry 8 (1997), S. 453-457 
    Details
    ISSN: 1572-9001
    Keywords: Benzopsoralen ; photochemotherapeutic agent ; crystal structure ; molecular mechanics ; AM1 theoretical calculations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract 5-Methoxy-4-methyl-2H-benzofuro[3,2-g]benzo-1-pyran-2-one was synthesized and its crystal structure was determined and compared with the optimal conformation arrived at by MM and AM1 theoretical calculations. The latter indicated that the tetracyclic skeleton is planar with total length (C2–C8) 9.23 å, and that the line joining the conters of the terminal-benzene and furan rings makes an angle of 30.5
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02311704
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Polymorphism of Inclusion Complexes and Unsolvated Hosts. II. Structure of the β-Dimorph of the Host-Guest Complex of Dianilinegossypol with Ethylacetate (1997)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 27 (1997), S. 105-112 
    Details
    ISSN: 1573-1111
    Keywords: β-Dimorph ; crystal structure ; dianilinegossypol ethylacetate 1 : 1 clathrate ; packing motifs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Depending on crystallization conditions, dianilinegossypol and ethylacetate form low (ambient temperature, α-phase) and high temperature (t = 35°C, β-phase) clathrate modifications. The structure of the α-phase has been discussed earlier [1]. Crystals of the 1 : 1 β-phase complex, C42H40O6N2·C4O2H8, are monoclinic, space group P21/c, a = 11.362(6), b = 19.479(9), c = 19.085(9) Å, β = 103.21(4)°, V = 4112(3)Å3, Z = 4, R = 0.084 for 3210 observed reflections. In these complexes centrosymmetric dimers of dianilinegossypol molecules formed via O(5)—H···O(3) hydrogen bonds are associated into columns by a weak O(8)—H···O(7) H-bond. A difference in the structure of these two phases is in the packing mode of the columns. The angle formed by intersecting host columns is about 126° for the α-phase and 104° for the β-modification. Guest molecules are hydrogen bonded to the host molecules via an O(1)—H···O(10) bond and are accommodated in channels in α-phase complex and in cavities in β-phase complex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007908530132
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Inclusion Compounds of NaI with 13-Membered Azo- and Azoxycrown Ethers (1997)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 28 (1997), S. 17-32 
    Details
    ISSN: 1573-1111
    Keywords: Azocrown ether ; azoxycrown ether ; sodium complexes ; crystal structure ; X-ray analysis ; conformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Sodium iodide complexes of 13-membered azo-(I)and azoxycrown ethers (II) have been synthesized. Compound I[Na(L1 trans)2]⋅I⋅H2O is triclinic witha = 11.53(2), b = 15.74(2), c = 19.17(2) Å,α = 98.93(9), β = 105.51(9),γ = 89.20(9) deg.; Z = 4, space groupP1. Compound II [Na(L2)2]⋅I is orthorhombic witha = 12.451(2), b = 13.796(3), c = 18.667(4)Å; Z = 4, space group P212121. In bothcomplexes the cation is coordinated tochain oxygen atoms and to one nitrogen atom of the azoor azoxy unit. The ability of bothligands to form complexes in relation to thegeometry of the azo or azoxy subunit of themacrocycle is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007929726695
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Crystal Structure of a Uranyl/p-tert-Butylcalix[5]arene Complex (1997)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 27 (1997), S. 13-20 
    Details
    ISSN: 1573-1111
    Keywords: Uranyl complexes ; calixarenes ; crystal structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The synthesis and crystal structure of the inclusion complex between uranyl and p-tert-butylcalix[5]arene are reported. [UO2 (p-tert-butylcalix[5]arene-4H]2- · $${\text{2HNE}}_{{\text{t}}_{\text{3}} }^{\text{ + }} $$ &·2MeOH(1) crystallizes in the monoclinic space group C2/c, a = 30.06(2), b = 18.20(3), c = 31.35(2) Å, β = 128.51(6)°, V = 13423(40) Å3, Z = 8. Refinement led to a final conventional R value of 0.043 for 4155 reflections. The uranyl ion is bonded, in its equatorial plane, to the five oxygen atoms of the calixarene, four of which are deprotonated. A protonated triethylamine molecule is located inside the calixarene cavity and hydrogen bonded to a uranyl oxygen atom, and another one outside and hydrogen bonded to a calixarene oxygen atom. The calixarene conformation is the usual cone one.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007938218723
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Synthesis, Structure and Alkali Metal Ion Binding Properties of a Podand Polyether Derived from Calix[4]arene, 5,11,17,23-tetra-tert-butyl-25,27-di(phenylmethoxy)-26,28-di(2‘-methoxyethoxy)-calix[4]arene (1997)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 27 (1997), S. 291-302 
    Details
    ISSN: 1573-1111
    Keywords: Calix[4]arene ; polyether ; crystal structure ; alkali metal ion binding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The ligand 5,11,17,23-tetra-t-butyl-25,27-di(phenylmethoxy)-26,28-di(2-methoxy-ethoxy)calix[4]arene,designed as an analogue of some calixcrown speciesin order to evaluate possible origins of their selectivity in alkali metal ion binding, has been synthesised and structurally characterised by X-ray crystallography. The crystals are monoclinic, P21/n, a = 15.940(6), b = 19.388(5), c = 20.020(5) Å,β = 109.10(2) deg., Z = 4, conventional R on |F| being 0.073 for 3454 independent, ’observed‘ (I 〉 3σ(I)) reflections. 1H-NMR studies in 1:1 CD3CN/CDCl3solvent have shown that the ligand exerts a strong preference for the lighteralkali metal ions (Li+ and Na+) contrary to the binding behaviour of knowncalixcrowns. This may reflect interactions restricted to the lower rim donor atoms without concomitant interaction with the calixarene π-electrons, perhaps because the latter interactions are substituted by those with the benzyl group π-electrons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007981710765
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 11
    Electronic Resource
    Electronic Resource
    Polymorphism of Inclusion Complexes and Unsolvated Hosts. V. Crystal Structure of the α-Dimorph of the 1 : 2 Dianilinegossypol–DMSO Complex and a 1 : 1 : 1 Inclusion Complex Based on a Mixed Dianilinegossypol/1,4-Dioxane Host Matrix and 1,2-Dichloroethane Guest (1997)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 29 (1997), S. 23-32 
    Details
    ISSN: 1573-1111
    Keywords: Dianilinegossypol ; crystal structure ; host–guest complexes ; H-bond ; α- and β-dimorphs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Dianilinegossypol forms a 1 : 2 host-guest complex with DMSO:monoclinic, space group P21/n, a = 8.522(3), b = 18.034(4), c= 28.462(6) Å, β = 94.14(2)°, V = 4362Å3, Z = 4, D x = 1.26 g cm-3, T = 295 K.Final R value is 0.102 for 1793 observed reflections. A 1 : 1 : 1 adduct ofdianilinegossypol with 1,4-dioxane and 1,2-dichloroethane is found to beisostructural with the dianilinegossypol complex with DMSO: monoclinic,space group P21/n, a = 8.281(2), b = 19.245(3), c = 27.970(7)Å, β = 95.18°, V = 4439 Å3, Z = 4, D x =1.28 g cm-3, T = 295 K. Final R value is 0.114 for 2458observed reflections.The host molecules are associated by O(4)—H ...O(3) H-bonds toinfinite chains running in the direction of the c-axis The chains areincorporated into layers through 1,4-dioxane or DMSO molecules havingH-bonds with dianilinegossypol molecules. Another DMSO or 1,2-dichloroethanemolecule is included as a guest in the channels formed between the layers.At 60 °C a cryptate-type inclusion complex of dianilinegossypol isformed with DMSO or 1,4-dioxane. It is isostructural with the acetonecomplex reported in Part IV of the present series.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007992116261
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    p-tert-Butylcalix[5]arene: a New Synthetic Pathway and Crystal Structure of the N,N-Dimethylformamide Complex (1997)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 29 (1997), S. 175-185 
    Details
    ISSN: 1573-1111
    Keywords: p-tert-Butylcalix[5]arene ; synthesis ; complexation ; crystal structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The formation of p-tert-butylcalix[5]arene by the opening ofp-tert-butyldihomooxacalix [4]arene and the addition of a monomer has beenstudied. Various facets, including the effects of bases and the nature ofthe monomer added to the p-tert-butyldihomooxacalix[4]arene, have beeninvestigated. p-tert-Butylcalix[5]arene can be prepared in yields up to30%. The structure of its 1 : 2 complex with DMF has been determinedby X-ray crystallography. Crystals are triclinic, space group P¯1, a =1428.2(3) pm, b = 1837.3(3) pm, c = 1276.1(2) pm, α = 108.98(1)°,β = 105.02(2)°, γ = 95.21(1)°, Z = 2, D c = 1.059 kg m-3,final R value = 0.087. The macrocycle adopts a cone conformation, one guestenclosed inside the cavity, the other one outside.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007907525620
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    Crystal Structures of 1,3-Calix[4]-bis-crown-6·3CH3CN and 1,3-Calix[4]-bis-(benzo-crown-6)·3 CH3CN (1997)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 27 (1997), S. 169-178 
    Details
    ISSN: 1573-1111
    Keywords: Bridged calix[4]arene ; ditopic receptor ; crystal structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The crystal structures of a new solvate of the ditopic receptor 1,3-calix[4]-bis-crown-6, Bis-C6, and of 1,3-calix[4]-bis-(benzo-crown-6), Bis-benzoC6, are reported. Bis-C6.3 CH3CN (1) crystallizes in the monoclinic space group P21/n, a = 14.388(3), b = 26.947(8), c = 14.707(4) Å, β = 113.19(3)°, V = 5241(5) Å3, Z = 4. Refinement led to a final conventional R value of 0.092 for 2723 reflections. The structure of (1) differs from the previously reported structure of Bis-C6.4 CH3CN by the conformation of one crown either chain. Two acetonitrile molecules are in the close neighbourhood of the crown ether cavities. Bis-benzoC6.3 CH3CN (2) crystallizes in the monoclinic space group P21/c, a = 10.391(4), b = 17.264(11), c = 30.426(9) Å, β = 94.62(3)°, V = 5440(7) Å3, Z = 4. Refinement led to a final conventional R value of 0.106 for 2965 reflections. Two acetonitrile molecules are located near the crown ether cavities, as in (1). One of the crown ether conformations is the same as in the binuclear caesium complex of Bis-benzoC6, supporting the hypothesis of a preorganization of this ligand towards the complexation of this ion; the second crown ether chain is partially disordered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007990208036
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    X-Ray Structure and Proton NMR Study of a Hexacoordinated Lithium Complex (1997)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 28 (1997), S. 125-140 
    Details
    ISSN: 1573-1111
    Keywords: X-ray ; crystal structure ; Li-complex ; triamides ; 1H-NMR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The structure of the lithium complex with1,3,5-tris[oxymethylene(N,N-dicyclohexyl)carboxyamido]cyclohexanehas been determined by the X-ray method.The compound is triclinic, space group P¯1,a = 15.623(3), b = 19.279(4),c = 19.295(4)Å α = 102.32(3), β = 92.45(3),γ = 105.67(3)0, V = 5436(2)Å3, Z = 4. Itscomposition is represented by the formulaC48H82N3O6LiI 0.5H2O. The lithium cationis encapsulated in a polar pseudo-cavity of six oxygen atoms of the ligandmolecule and displays a distorted trigonal prism coordination. The conformationof the ligand in the solid state complex has been compared with the conformationof the complex in solution determined by 1H-NMR measurements. Supplementary data relevant to this publication have been deposited with the British Library, No. SUP 82224 (21 pages).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007955923966
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    Synthesis of Two New Glycophanes Comprised of Thioglucose Molecules Linked by Hydrocarbons (1997)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 29 (1997), S. 335-346 
    Details
    ISSN: 1573-1111
    Keywords: Glycophane ; macrocycle ; carbohydrate ; crystal structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Preparation of two new glycophanes is reported. These compounds arecomprised of two glucose molecules linked by hydrocarbon units at the 1,1′ and 3, 3′ or 3, 3′ and 6, 6′ positions. Thecrystal structure of one of the glycophanes is also described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007952822709
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    Large differences are observed between the crystal and solution quaternary structures of allosteric aspartate transcarbamylase in the R state (1997)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 27 (1997), S. 110-117 
    Details
    ISSN: 0887-3585
    Keywords: small-angle scattering ; x-rays ; allosteric enzymes ; crystal structure ; rigid body modeling ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Solution scattering curves evaluated from the crystal structures of the T and R states of the allosteric enzyme aspartate transcarbamylase from Escherichia coli were compared with the experimental x-ray scattering patterns. Whereas the scattering from the crystal structure of the T state agrees with the experiment, large deviations reflecting a significant difference between the quaternary structures in the crystal and in solution are observed for the R state. The experimental curve of the R state was fitted by rigid body movements of the subunits in the crystal R structure which displace the latter further away from the T structure along the reaction coordinates of the T→R transition observed in the crystals. Taking the crystal R structure as a reference, it was found that in solution the distance between the catalytic trimers along the threefold axis is 0.34 nm larger and the trimers are rotated by 11° in opposite directions around the same axis; each of the three regulatory dimers is rotated by 9° around the corresponding twofold axis and displaced by 0.14 nm away from the molecular center along this axis. Proteins 27:110-117 © 1997 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 17
    Electronic Resource
    Electronic Resource
    Computational, pulse-radiolytic, and structural investigations of lysine-136 and its role in the electrostatic triad of human C u,Z n superoxide dismutase (1997)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 29 (1997), S. 103-112 
    Details
    ISSN: 0887-3585
    Keywords: Brownian dynamics ; molecular recognition ; site-directed mutagenesis ; facilitated diffusion ; crystal structure ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Key charged residues in Cu,Zn superoxide dismutase (Cu,Zn SOD) promote electrostatic steering of the superoxide substrate to the active site Cu ion, resulting in dismutation of superoxide to oxygen and hydrogen peroxide. Lys-136, along with the adjacent residues Glu-132 and Glu-133, forms a proposed electrostatic triad contributing to substrate recognition. Human Cu,Zn SODs with single-site replacements of Lys-136 by Arg, Ala, Gln, or Glu or with a triple-site substitution (Glu-132 and Glu-133 to Gln and Lys-136 to Ala) were made to test hypotheses regarding contributions of these residues to Cu,Zn SOD activity. The structural effects of these mutations were modeled computationally and validated by the X-ray crystallographic structure determination of Cu,Zn SOD having the Lys-136-to-Glu replacement. Brownian dynamics simulations and multiple-site titration calculations predicted mutant reaction rates as well as ionic strength and pH effects measured by pulse-radiolytic experiments. Lys-136-to-Glu charge reversal decreased dismutation activity 50% from 2.2 × 109 to 1.2 × 109 M-1 s-1 due to repulsion of negatively charged superoxide, whereas charge-neutralizing substitutions (Lys-136 to Gln or Ala) had a less dramatic influence. In contrast, the triple-mutant Cu,Zn SOD (all three charges in the electrostatic triad neutralized) surprisingly doubled the reaction rate compared with wild-type enzyme but introduced phosphate inhibition. Computational and experimental reaction rates decreased with increasing ionic strength in all of the Lys-136 mutants, with charge reversal having a more pronounced effect than charge neutralization, implying that local electrostatic effects still govern the dismutation rates. Multiple-site titration analysis showed that deprotonation events throughout the enzyme are likely responsible for the gradual decrease in SOD activity above pH 9.5 and predicted a pKa value of 11.7 for Lys-136. Overall, Lys-136 and Glu-132 make comparable contributions to substrate recognition but are less critical to enzyme function than Arg-143, which is both mechanistically and electrostatically essential. Thus, the sequence-conserved residues of this electrostatic triad are evidently important solely for their electrostatic properties, which maintain the high catalytic rate and turnover of Cu,Zn SOD while simultaneously providing specificity by selecting against binding by other anions. Proteins 29:103-112, 1997. © 1997 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 18
    Electronic Resource
    Electronic Resource
    Bactericidal antibody recognition of a PorA epitope of Neisseria meningitidis: Crystal structure of a Fab fragment in complex with a fluorescein-conjugated peptide (1997)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 29 (1997), S. 113-125 
    Details
    ISSN: 0887-3585
    Keywords: bactericidal antibody ; crystal structure ; Neisseria meningitidis ; peptide-fluorescein conjugate ; PorA outer membrane protein ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Class 1 outer membrane protein PorA of Neisseria meningitidis is a vaccine candidate against bacterial meningitis. Antibodies against PorA are able to induce complement-mediated bacterial killing and thereby play an important role in protection against meningococcal disease. Bactericidal antibodies are all directed against variable regions VR1 and VR2 of the PorA sequence, corresponding to loops 1 and 4 of a two-dimensional topology model of the porin with eight extracellular loops. We have determined the crystal structure to 2.6 Å resolution of the Fab fragment of bactericidal antibody MN12H2 against meningococcal PorA in complex with a linear fluorescein-conjugated peptide TKDTNNNL derived from the VR2 sequence of sero-subtype P1.7,16 (residues 180-187) from meningococcal strain H44/76. The peptide folds deeply into the binding cavity of the Fab molecule in a type I β-turn, with the minimal P1.16 epitope DTNNN virtually completely buried. The structure reveals H-bonds and van der Waals interactions with all minimal epitope residues and one essential salt bridge between Asp-182 of the peptide and His-31 of the MN12H2 light chain. The key components of the recognition of PorA epitope P1.16 by bactericidal antibody MN12H2 correspond well with available thermodynamic data from binding studies. Furthermore, they indicate the structural basis of an increased endemic incidence of infection by group B meningococci in England and Wales since 1981 associated with the occurrence of an Neisseria meningitidis escape mutant (strain MC58). The observed three-dimensional conformation of the peptide provides a rationale for the development of a synthetic peptide vaccine against meningococcal disease. Proteins 29:113-125, 1997. © 1997 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 19
    Electronic Resource
    Electronic Resource
    The crystal structure of 1,4-benzenedithiol by rietveld analysis and studies on the mechanism of solid-state addition polymerization of 1,4-benzenedithiol to 1,4-diethynylbenzene (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 1621-1625 
    Details
    ISSN: 0887-624X
    Keywords: 1,4-benzenedithiol ; 1,4-diethynylbenzene ; crystal structure ; solid-state polymerization ; layer structure ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The crystal structure of 1,4-benzenedithiol (BDT) was determined by the Rietveld method based on the calculation of the atomic coordinates of the BDT molecule using the Molecular Mechanics Program (MMP2). The refined crystal structure of BDT was monoclinic P21/c with dimensions, a = 7.795, b = 7.290, c = 5.955 Å, β = 92.16°, z = 2. The R factor of the refined structure was 0.038. Using above results, the mechanism of solid-state addition polymerization of BDT to 1,4-diethynylbenzene (DEB) was studied. Sublimed BDT piles up onto glass plate substrate and forms the layer structure along with the a axis. An inclination angle of the piled BDT column was 60° toward the substrate surface. DEB crystal structure was also monoclinic P21/c with a = 4.007, b = 6.018; c = 15.340 Å, β = 91.42°, z = 2. Sublimation of equimolar mixture of BDT and DEB gave a crystal having 1 : 1 composition, in which DEB column is situated between the columns of BDT. Relative arrangement of both monomers was suitable for the addition of —SH and —C=CH groups, since the distance between the two groups is 3.3 Å by CERIUS II calculation. Therefore, the addition polymerization of BDT to DEB easily proceeded by UV irradiation and the resulting polymer had a highly layer structure along with the a axis of BDT crystal. Tentatively estimated crystal structure of polymer obtained is monoclinic with a = 7.73, b = 7.30, c = 5.95 Å, β = 92.16°. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1621-1625, 1997
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 20
    Electronic Resource
    Electronic Resource
    Crystal structure of the bovine α-chymotrypsin:kunitz inhibitor complex. An example of multiple protein:protein recognition sitesThis paper is dedicated to Professor A. Ballio on the occasion of his 75th birthday. (1997)
    Chicester [u.a.] : Wiley-Blackwell
    Journal of Molecular Recognition 10 (1997), S. 26-35 
    Details
    ISSN: 0952-3499
    Keywords: bovine α-chymotrypsin ; bovine basic pancreatic trypsin inhibitor (Kunitz-type inhibitor) ; serine proteinase:Kunitz inhibitor complex ; crystal structure ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The crystal structure of bovine α-chymotrypsin (α-CHT) in complex with the bovine basic pancreatic trypsin inhibitor (BPTI) has been solved and refined at 2.8 Å resolution (R-factor=0.18). The proteinase:inhibitor complex forms a compact dimer (two α-CHT and two BPTI molecules), which may be stabilized by surface-bound sulphate ions, in the crystalline state. Each BPTI molecule, at opposite ends, is contacting both proteinase molecules in the dimer, through the reactive site loop and through residues next to the inhibitor's C-terminal region. Specific recognition between α-CHT and BPTI occurs at the (re)active site interface according to structural rules inferred from the analysis of homologous serine proteinase:inhibitor complexes. Lys15, the P1 residue of BPTI, however, does not occupy the α-CHT S1 specificity pocket, being hydrogen bonded to backbone atoms of the enzyme surface residues Gly216 and Ser217. © 1997 John Wiley & Sons, Ltd.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 21
    Electronic Resource
    Electronic Resource
    The Unusual Properties of 5-Methyl-4,5,6,7-Tetrahydro-1H-Indazole in the Solid State (1997)
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 3 (1997), S. 121-126 
    Details
    ISSN: 0947-6539
    Keywords: crystal structure ; NMR spectroscopy ; proton transfer ; pyrazoles ; tautomerism ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The crystal structure of the title compound was determined by X-ray analysis at 200 K. Three independent molecules form a trimer joined by strong and linear N-H … N hydrogen bonds. There is another centrosymmetrically related trimer in the unit cell. Both tautomers (1H and 2H) are present in each trimer. Disorder of the NH protons involved in the N-H … N hydrogen bonds has been observed. Solid-state 13C CPMAS NMR was used to establish the dynamic nature of the NH-proton disorder, the title compound being the first example of proton transfer in a tautomeric mixture of pyrazoles with an equilibrium constant other than 1.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chem.19970030119
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 22
    Electronic Resource
    Electronic Resource
    Synthesis of Pyrazinoporphyrazine Derivatives Functionalised with Tetrathiafulvalene (TTF) Units: X-Ray Crystal Structures of Two Related ttf Cyclophanes and Two Bis(1,3-Dithiole-2-Thione) IntermediatesDedicated to Professor Fabian Gerson on the occasion of his retirement (1997)
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 3 (1997), S. 1679-1690 
    Details
    ISSN: 0947-6539
    Keywords: crystal structure ; cyclophanes ; electrochemistry ; porphyrazines ; tetrathiafulvalenes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The pyrazinoporphyrazine system 13 (metal-free, zinc and copper derivatives) has been synthesised by tetramerisation of 2,3-dicyanopyrazine monomer unit 10. The structure of 13a-c has been established by 1H NMR spectroscopy, UV/Vis spectrophotometry, MALDI-TOF mass spectrometry, cyclic voltammetry and differential pulse voltammetry. The electrochemical redox behaviour of 13a-c is strongly solvent dependent. The expected two-stage oxidation of the tetrathiafulvalene (TTF) units of 13a-c was observed in a range of solvents; in addition, oxidation and reduction of the pyrazinoporphyrazine core of the metal-free derivative 13a was detected in benzonitrile. On excitation of 13 in the Q-band region no fluorescence was observed, which is presumably the consequence of intramolecular charge transfer between the TTF moieties and the excited state of the central porphyrazine. Molecular modelling studies on 13a and 13c are reported. During the course of this work, the novel TTF macrocycles 11 and 20 were synthesised; their X-ray crystal structures reveal severely bent TTF units, the conformations of which are discussed in detail. The X-ray crystal structures of the bis(1,3-dithiole) systems 15 and 18 have also been determined.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chem.19970031018
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 23
    Electronic Resource
    Electronic Resource
    The crystal and molecular structures of cellulose I and II (1997)
    Springer
    Glycoconjugate journal 14 (1997), S. 677-690 
    Details
    ISSN: 1573-4986
    Keywords: molecular dynamics ; crystal structure ; cellulose I and II
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The paper describes molecular dynamics (MD) simulations on the crystal structures of the Iβ and II phases of cellulose. Structural proposals for each of these were made in the 1970s on the basis of X-ray diffraction data. However, due to the limited resolution of these data some controversies remained and details on hydrogen bonding could not be directly obtained. In contrast to structure factor amplitudes in X-ray diffraction, energies, as obtained from MD simulations, are very sensitive to the positions of the hydroxyl hydrogen atoms. Therefore the latter technique is very suitable for obtaining such structural details. MD simulations of the Iβ phase clearly shows preference for one of the two possible models in which the chains are packed in a parallel orientation. Only the parallel-down mode (in the definition of Gardner and Blackwell (1974) J Biopolym 13: 1975-2001) presents a stable structure. The hydrogen bonding consists of two intramolecular hydrogen bonds parallel to the glycosidic linkage for both chains, and two intralayer hydrogen bonds. The layers are packed hydrophobically. All hydroxymethyl group are positioned in the tg conformation. For the cellulose II form it was found that, in contrast to what seemed to emerge from the X-ray fibre diffraction data, both independent chains had the gt conformation. This idea already existed because of elastic moduli calculations and 13C-solid state NMR data. Recently, the structure of cellotetraose was determined. There appear to be a striking similarity between the structure obtained from the MD simulations and this cellotetraose structure in terms of packing of the two independent molecules, the hydrogen bonding network and the conformations of the hydroxymethyl group, which were also gt for both molecules. The structure forms a 3D hydrogen bonded network, and the contribution from electrostatics to the packing is more pronounced than in case of the Iβ structure. In contrast to what is expected, in view of the irreversible transition of the cellulose I to II form, the energies of the Iβ form is found to be lower than that of II by 1 kcal mol-1 per cellobiose.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018509231331
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 24
    Electronic Resource
    Electronic Resource
    On the dynamics of a linear and a nonlinear quantum oscillator with randomly changing harmonic frequency (1997)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 62 (1997), S. 265-272 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Numerical experiments with a nonlinear (λχ4) oscillator which has its harmonic frequency changing randomly with time reveal certain interesting features of its dynamics of quantum evolution. When λ = 0, the level populations are seen to oscillate. But, as the nonlinear coupling is switched on (λ 〉 0), a threshold is reached at λ = λc when the evolution is seen to be characterized by an abrupt transition dominantly to the highest available state of the unperturbed (initial) oscillator. It is shown that this transition probability is maximized at a particular value of λ. The time threshold for this transition decreases with increasing nonlinear coupling strength. The numerically obtained structures of the underlying quantum-phase spaces of the linear and nonlinear random oscillators are examined. Possible use of these results in a problem of chemical origin is explored. © 1997 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 25
    Electronic Resource
    Electronic Resource
    Electronic structure of testosterone: A semiempirical and ab initio assessment (1997)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 62 (1997), S. 279-289 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Testosterone (17β-hydroxy-4-androsten-3-one) was studied by the semiempirical AM1 and PM3 and ab initio STO-3G*, 3-21G*, and 6-31G* methods. The goals were to compare those methods and to know the electronic structure of the hormone. Full geometry optimization was performed, and two crystal conformers (T1 and T2), and experimental dipole moment in solution were used for comparison. One conformer with a dipole moment similar to the solvated conditions was generated. Total energy, entalphies, dipole moments, charges, electrostatic potentials, and highest occupied molecular orbitals (HOMO) and lowest unoccupied molecular orbital (LUMO) were calculated. Root-mean-square (RMS) index of the theoretical molecules against T1 and T2 showed best results with the 3-21G* and 6-31G* methods, while AM1 gave better energies than PM3. Dipole moments were directed toward the OH group and the botton face of the A ring. The frontier orbitals were located along the C4-C5 π bond, particularly the LUMO was split between C4 and C5, predicting the action of enzymes at C5 yielding to 5α and 5β-reduced androgens. Electrostatic potentials might be also of biological importance since they are coincidental with the dipole-moment orientation. Finally, it is interesting that the solvatedlike conformer, its properties, and the OH group laid between the same group of T1 and T2 and with a total energy between the crystals and the gas phase or in vacuo conditions. This results might also explain the biology of testosterone and use them to model the hormone-receptor interaction. © 1997 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 26
    Electronic Resource
    Electronic Resource
    Photoelectron spectra of molecules. II. Carboxylic acids and their esters (1997)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 62 (1997), S. 303-314 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: He I photoelectron (PE) spectra of four carboxylic acids and five esters are measured. Semiempirical and ab initio quantum chemical calculations are used for the interpretation of the spectra. The complex approach which uses empirically established relationships (the dependence of valence electron ionization energies on proton affinities in the gas phase, on the core level ionization energies, and on the structure) was developed. © 1997 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 27
    Electronic Resource
    Electronic Resource
    Molecular orbital analysis of chemical carcinogens (1997)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 62 (1997), S. 323-328 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Simple molecular orbital calculations are employed in searching electronic parameters which may characterize the chemical carcinogens. Using frontier orbitals, the carcinogen-DNA bond formation is described as an electron transfer from the highest occupied molecular orbital (HOMO) of DNA to the lowest unoccupied molecular orbital (LUMO) of the carcinogen. Analysis of the DNA bases units shows that the electron donation occurs preferentially at the guanine site. The calculated low LUMO energy of several carcinogens indicate correctly the electrophilic character of these compounds. The difference between the carcinogen and the ultimate carcinogen is analyzed. Epoxides, free radicals, alkylating agents, and other metabolite forms are studied. A reasonable correlation is found between the LUMO energy and the carcinogenic function. © 1997 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 28
    Electronic Resource
    Electronic Resource
    Molecular dynamics simulation of the free surface of liquid formamide (1997)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 63 (1997), S. 1123-1131 
    Details
    ISSN: 0020-7608
    Keywords: MD simulations ; liquid surface ; formamide ; molecular orientation ; molecular surface density ; Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Molecular dynamics simulations of liquid formamide(HCONH2) were carried out using the GROMOS software. The formamide molecule is represented by all of its atoms with all internal degrees of freedom. In contrast to other simulations dealing with bulk properties, this study focuses on the interface liquid-vacuum for the first time. We show that the molecular plane is tilted out of the surface, exposing the HCO group to the vacuum.   © 1997 John Wiley & Sons, Inc. Int J Quant Chem 63: 1123-1131, 1997
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 29
    Electronic Resource
    Electronic Resource
    A very accurate grid method for the solution of Schrödinger equations: The helium ground state (1997)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 63 (1997), S. 1065-1078 
    Details
    ISSN: 0020-7608
    Keywords: very precise eigenvalues ; very accurate grid method ; general solution for Schrödinger equations ; rapidly convergent treatment for helium eigenvalues ; superconvergence ; optimization of grids ; treatment of continuum ; Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An extension to the theory of Schrödinger equations has been made which enables the derivation of eigenvalues from a consideration of a very small part of geometric space. The concomitant unwanted continuum effects have been removed. The theory enables very convergent or “superconvergent” calculations. In the case of the helium ground state, E=-2.90372437703411987 Eh was obtained from 251 terms. The result is comparable to that from the largest variation calculations so far carried out reinforced by extrapolation techniques. The theory is extensible to atoms and molecules irrespectively of the number of electrons or nuclear centers. In these cases, the advantage of “superconvergent” calculations will be more pronounced than in the case of helium.   © 1997 John Wiley & Sons, Inc. Int J Quant Chem 63: 1065-1078, 1997
    Additional Material: 9 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 30
    Electronic Resource
    Electronic Resource
    Noninteger principal quantum numbers increase the efficiency of Slater-type basis sets (1997)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 62 (1997), S. 1-11 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Roothaan-Hartree-Fock (RHF) calculations are carried out for the ground states of the atoms from helium to xenon using a minimal basis set of Slater-type functions whose principal quantum numbers are allowed to take variationally optimal noninteger values. The resulting energies are substantially superior to those obtained previously under the usual restriction that principal quantum numbers be positive integers. The energy lowering relative to the single-zeta wave functions of Clementi and co-workers ranges from 0.0066 Eh in He to 11.2 Eh in Xe. Our results are superior to those obtained by Höjer using a minimal basis set of unconventional binomially screened basis functions. Noninteger principal quantum numbers benefit d-orbitals the most; physically realistic negative d-orbital energies are obtained in all cases including those transition-metal atoms for which a conventional single-zeta STF basis leads to positive d-orbital energies. © 1997 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 31
    Electronic Resource
    Electronic Resource
    Ab initio study on the reaction of Sc+ + CH4 → Sc+(SINGLE BOND)CH2 + H2 (1997)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 62 (1997), S. 23-27 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An ab initio study on the reaction of the ground state (3D) and the excited state (1D) of Sc+ with methane was performed. Reaction channels on the singlet and triplet potential surface (PES) and the reaction mechanism are examined and discussed. Three regions of the potential surface was studied: the molecular complex, the C(SINGLE BOND)H insertion products, and the transition states for the reaction. Comparisons between singlet and triplet PESs show that the excited state (1D) of Sc+ has more reactivity with methane than does the ground state (3D) due to the spin quantum number conservation with the more stable insertion intermediate. © 1997 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 32
    Electronic Resource
    Electronic Resource
    Influence of hybridization displacement charge on the description of electrostatic potentials of molecules with multiple electrophilic sites (1997)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 62 (1997), S. 67-76 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The importance of the hybridization displacement charge (HDC) in describing molecular electrostatic potential (MEP) maps was demonstrated by studying six molecules; pyrazine N-oxide, para-nitropyridine, 5-nitropyrimidine, 3-nitropyridazine, N2, and N2O. It is shown that continuously distributed HDC-corrected Löwdin charges reproduce the MEP features of these molecules, most of which have competing electrophilic sites, in agreement with ab initio results. Further, it is found that for homonuclear diatomic molecules MEP minima can be located properly using HDC-corrected Löwdin (or HDC-corrected Mulliken) continuously distributed charges, but these features cannot be obtained using the conventional Löwdin (or Mulliken) charges. It was shown that the order of molecular electric field (MEF) values near the different electrophilic sites becomes changed when one moves away from the molecules. Thus, pyridine-type nitrogen atoms are the preferred binding sites close to the molecules, while at large distances, effects of oxygen atoms of the NO groups become dominant. © 1997 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 33
    Electronic Resource
    Electronic Resource
    Crystalline and local vibrations of paired bases in poly(dG)-poly(dC) interacting with the h-b-1 hydrogen bond (1997)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 62 (1997), S. 115-124 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Some types of atomic vibrations in a chain of the DNA type constructed of G-C pairs were studied. These are the atomic vibrations of the lateral groups of guanine and N(3)H(1)H(2) of cytosine connected by the hydrogen bond h-b-1 and the vibrations of the centers of masses of bases in the direction parallel to bonds h-b-i, i = 1-3. The vibrations mix partially due to the dependence of the energy of the bond h-b-1 on its length and split into two bands because of the interaction between neighboring base pairs. It was shown that the excitation of the bond h-b-1 results in the splitting off of the two local vibrations and in a small deformation of the chain in the vicinity of the pair with the localized hydrogen bond. The law of the dispersion of band vibrations, values of the split-off frequencies, and degree of poly(dG)-poly(dC) chain deformation were determined. © 1997 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 34
    Electronic Resource
    Electronic Resource
    Modeling properties of the HF dimer in argon clusters (1997)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 62 (1997), S. 55-65 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We compare geometry configurations, vibrational properties, and electronic structures of (HF)2 in a free state and inside argon atom shells Arn. For the first stage, molecular dynamics calculations for the (HF)2 · Ar62 heterocluster are performed with the help of model potentials HF(SINGLE BOND)HF, Ar(SINGLE BOND)Ar, and Ar(SINGLE BOND)HF. Then, ab initio quantum chemistry analysis is carried out for the smaller systems (HF)2 · Ar15 and (HF)2 · Ar6 when keeping the argon atoms closest to the trapped dimer. We conclude that the hydrogen-bonded complex (HF)2 gains some extra stability inside the argon shells, originating primarily from a decrease of intermolecular distance RFF. Electronic structure calculations are in accord with the changes in dynamical properties, namely, a noticeable increase in the vibrational frequency assigned to the F(SINGLE BOND)F stretching mode (+25 cm-1) and decrease in rms deviations for the corresponding coordinate δFF. In addition to these changes, the argon atoms of the nearest solvent shell donate a small fraction of electron charge which is spent for an increase of population of the antibonding orbital σ*Hf(SINGLE BOND)Ff of the free monomer unit and shift orbital energies primarily of the lone-pair fluorine species. These shifts are greater than the changes due to geometry alterations and the possible inaccuracies of the calculation scheme. © 1997 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 35
    Electronic Resource
    Electronic Resource
    Efficient evaluation of the algebrants of VB wave functions using the successive expansion method. I. Spin S = 0, ½ (1997)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 62 (1997), S. 245-259 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An efficient expansion method for the evaluation of VB matrix elements is introduced. The overlaps of VB wave functions of N electrons can be treated as algebrants, i.e., generalized determinants, of N × N matrices. An algebrant can be expanded with subalgebrants of lower orders in a successive way. By choosing Rumer spin bases and appropriately arranging the expansion, it is found that the number of unique subalgebrants involved in the expansion increases in a quite moderate way with N. In contrast to the traditional symmetric group approach, which explicitly utilizes all N! representation matrices, the new strategy incorporates the group theoretical factors in a simple way in the successive expansion. As only the unique subalgebrants are further expanded, the computational effort required by the new strategy scales in a very acceptable manner with the increasing number of electrons. © 1997 John Wiley & Sons, Inc. Int J Quant Chem 62: 245-259, 1997
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 36
    Electronic Resource
    Electronic Resource
    Characters of two-row representations of the symmetric group (1997)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 62 (1997), S. 261-264 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Characters of irreducible representations (irreps) of the symmetric group corresponding to the two-row Young diagrams, i.e., describing transformation properties of N-electron eigenfunctions of the total spin operators, have been expressed as explicit functions of the number of electrons N and of the total spin quantum number S. The formulas are useful in various areas of theory of many-electron systems, particularly in designing algorithms for evaluation of spectral density moments. © 1997 John Wiley & Sons, Inc.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 37
    Electronic Resource
    Electronic Resource
    Computation of bond dissociation energy for sulfides and disulfides with ab initio and density functional theory methods (1997)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 62 (1997), S. 291-296 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The geometries and S-H, S-S, and S-C bond dissociation energies for hydrogen sulfide, hydrogen disulfide, methanethiol, dimethyl disulfide, and dimethyl disulfide were calculated with both ab initio (ROHF and MP2), hybrid (BHandH, BHandHLYP, Becke3LYP and Becke3P86), and nonlocal (BLYP and BP86) density functional theory (DFT) methods. In all studies the 6-31 + G(d) basis set is used. The computed results are compared to the experimentally obtained values, targeting the selection of a suitable ab initio or DFT method for the study of these systems. © 1997 John Wiley & Sons, Inc.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 38
    Electronic Resource
    Electronic Resource
    Theoretical study on the pyrolysis mechanism and kinetics of β-hydroxyketones (1997)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 62 (1997), S. 297-302 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mechanism and kinetics for the decomposition of β-hydroxypropaldehyde, primary and secondary β-hydroxyketones, were studied by using ab initio RHF/6-31G and RHF/6-31G* methods. The activation barriers of these reactions were refined to be 39.57, 40.10, and 36.80 kcal mol-1 at the MP2/ /RHF/6-31G* level, respectively. The calculated results show that each decomposition is a concerted process with hydrogen transferring and bond breaking via a six-membered cyclic transition state. The thermal rate constants of the decomposition of primary and secondary β-hydroxyketones were obtained by calculating microcanonical probability fluxes through each transition state. It is theoretically confirmed that methyl substitution at the hydroxyl carbon of β-hydroxyketones causes a small enhancement in rates. The theoretical investigations of the mechanism and the rate constants are in agreement with the experimental results. © 1997 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 39
    Electronic Resource
    Electronic Resource
    Numerical solution for the ground-state energy of the anisotropic Heisenberg model (1997)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 62 (1997), S. 13-21 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An analysis of the anisotropic Heisenberg model is carried out by solving the Bethe ansatz solution of the model numerically as a function of the anisotropy parameter for finite N. A brief introduction to the limit of the infinite chain is presented. The energy for a few special limiting cases of the anisotropy parameter in the Hamiltonian are worked out. Numerical results for finite cycles as well as for the infinite chain are given. Comparison can then be made with the case of finite increasing N. © 1997 John Wiley & Sons, Inc.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 40
    Electronic Resource
    Electronic Resource
    Evaluation of a characteristic atomic radius by an ab initio method (1997)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 62 (1997), S. 47-53 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The MELD program is employed to evaluate the Slater average potential v(r) felt by an electron at the point r within an atom. The characteristic radius R of the atom is then defined by the classical turning point equation v(R) = -I, where I denotes the first ionization potential of the atom. The atomic radii defined in this way have a close correlation with the van der Waals atomic radii. © 1997 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 41
    Electronic Resource
    Electronic Resource
    Accurate nonrelativistic energies for 2Pe states of the Li isoelectronic series (1997)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 62 (1997), S. 77-88 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Highly accurate upper bounds for several 2Pe states of the Li isoelectronic series obtained by extensive Hylleraas-Cl calculations are given. The best value for the 22Pe state (1s2p2) of Li is -5.21373920 au. The evaluation of the occurring integrals is given explicitly. Additionally, we present some expectation values and isotope energies of the Li isoelectronic series. © 1997 John Wiley & Sons, Inc.
    Additional Material: 11 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 42
    Electronic Resource
    Electronic Resource
    Hydrogen-bonding effects, electrostatic potential, and the antitumor activity of flavone acetic acid and related compounds. III. Ab initio studies on the conformation space (1997)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 62 (1997), S. 97-113 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Restricted geometry optimizations at the ab initio SCF level with the 3-21G basis set were employed to investigate the conformation space of flavone acetic acid (FAA) and its related compounds. All the conformations are produced from a conformation which is, according to our previous work, probably the active conformation in terms of antitumor activity shown by these compounds. Detailed studies on FAA were carried out while only brief discussions are made on the analogs. The main results obtained are that (1) FAA is a very flexible molecule, e.g., with the energy barrier up to about 3 kcal mol-1 from the reference conformation, the important torsional angle τ1 can change from 27.0° to 117.0°, τ2 from -168.0° to 2.0°, and τ3 from -50.0° to 30.0°; (2) the hydrogen-bonding effect plays an important role in determining lower-energy conformations; (3) among all the FAA conformations considered, some are active and some are inactive; (4) it seems that the analogs will have similar behavior to FAA when the torsional angle τ3 is restricted to the values which are around the equilibrium values; and (5) the hypothesis put forward previously has been further developed in this work. Now, we postulate that efficient charge transfers will lower the energy and that proper charge transfers will activate the molecule. There are mainly two different types of charge transfer corresponding to two different types of conformation, which are specified in this article. © 1997 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 43
    Electronic Resource
    Electronic Resource
    Evaluation of screened nuclear attraction and electron repulsion molecular integrals over Gaussian basis functions (1997)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 62 (1997), S. 273-278 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Analytical solutions to the Yukawa-like screened Coulomb nuclear attraction and electron repulsion molecular basic integrals, as well as to the basic integrals required to compute the virial coefficient, over Gaussian basis functions, are derived and cast into a practical closed form, suitable to interface with modern codes for the calculation of molecular electronic structure. © 1997 John Wiley & Sons, Inc.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 44
    Electronic Resource
    Electronic Resource
    Power series with rational coefficients for two-electron atom energies (1997)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 63 (1997), S. 1079-1089 
    Details
    ISSN: 0020-7608
    Keywords: large-order perturbation theory ; lie algebra ; three-body problem ; symbolic computations ; helium atom ; Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The method of o(4, 2) operator replacements is generalized. As a result, the series whose limiting values when the variable goes to  +∞ should correspond to the two-electron atom energies now have rational coefficients. This generalization allows one also to compute the series for the case of singlet S symmetry, a case which could not be considered in the previous original formulation of the method. Series with rational coefficients for the helium singlet and triplet S ground-state energy are calculated up to order 41 and 45, respectively. Moreover, symbolic computations also allow one to give the first few coefficients of these series for arbitrary values of the nuclear charge Z. Finally, a new method for analytic continuation to the limit  +∞ is presented for the energies of the helium singlet and triplet ground states.   © 1997 John Wiley & Sons, Inc. Int J Quant Chem 63: 1079-1089, 1997
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 45
    Electronic Resource
    Electronic Resource
    A study of bond-cleavage and bond-formation processes in some simple metathesis reactions (1997)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 63 (1997), S. 1099-1106 
    Details
    ISSN: 0020-7608
    Keywords: metathesis reactions ; bond order ; free valence ; minimum energy path ; nonsynchronization ; Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A few simple atom-transfer reactions (i.e., Ȧ+X-A→A-X+Ȧ) are studied by quantum mechanical ab initio methods. Emphasis is given to the detailed analysis of density matrices rather than to the energetics. Results reveal that during these reactions a small free valence always develops on the migrating atom at the transition state. The barriers in these reactions arise from the greater extent of bond cleavage in the reactant than that of bond formation in the transition state. Analysis of bond orders estimated from bond lengths using Pauling's relation also leads to the fact that the bond-cleavage process is more advanced than is the bond-formation process in these reactions.   © 1997 John Wiley & Sons, Inc. Int J Quant Chem 63: 1099-1106, 1997
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 46
    Electronic Resource
    Electronic Resource
    Theoretical study on Pd dimer and trimer interaction with the hydrogen molecule (1997)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 62 (1997), S. 29-45 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The H2 interaction with the Pd dimer and trimer were studied using multiconfigurational self-consistent field (MC-SCF) calculations with the relativistic effective core potential (RECP); the correlation energy correction was included in the extended multireference configuration interaction (MRCI), variational and perturbative to second order. Here, we considered the Pd2 first six states: 3Σ+u, 1Σ+g, 3Πg, 3Δxy, 1Σ+u, and 3Σ+g. For them, the four geometrical approaches included were the side-on H2 toward Pd2, for the hydrogen molecule in and out the Pd dimer plane; the perpendicular end-on H2 toward Pd2; and the perpendicular end-on Pd2 to H2. The Pd2 ground state is 3Σ+u, which only captures H2 in the C2v end-on approach, softly relaxing the H(SINGLE BOND)H bond. The closed-shell 1Σ+g captures the H2 molecule in all the approaches considered: The side-on approach of this state presents deep wells and relaxes the H(SINGLE BOND)H bond, and the end-on approach captures H2 with a relatively longer H(SINGLE BOND)H distance and also a deep well. The 3Πg state was the only one which did not capture H2. For the triangular Pd3 clusters, H2 was approached in the C2v symmetry in and out of the Pd3 plane. In the triangular case, H2 was absorbed in both spin states, with deep wells and relaxing the H(SINGLE BOND)H distance. The linear Pd3 singlet and triplet states capture outside of the Pd3 and break the H(SINGLE BOND)H bond. © 1997 John Wiley & Sons, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 47
    Electronic Resource
    Electronic Resource
    Total and partial decay widths in vibrational predissociation of the HeI2 van der Waals complex for lower initial vibrational excitations (1997)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 62 (1997), S. 89-96 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We presented a calculation of the total and partial decay widths of vibrational predissociation (VP) of the HeI2 molecule for low initial vibrational excitations from the lowest van der Waals (vdW) state with total angular momentum J = 0. A time-dependent golden rule wave-packet method was employed in our numerical calculations for the decay widths. The computed total decay widths, lifetimes, and rates of VP are in fairly good agreement with those extrapolated from the experimental data available. Predicted total decay widths as a function of initial vibrational levels exhibit a highly nonlinear behavior. These results demonstrate that a quantum mechanical decay mode for low vibrational excitation remains as well. The total propagation time needed in the time-dependent golden rule wave-packet calculations is much shorter than is the lifetime of the predissociation of HeI2. It is shown that the final-state interaction between the fragments is important for determining the final rotational-state distribution (partial decay width). We find that the major peak position in the final rotational-state distribution shifts to lower rotational energy levels with increase of the initial vibrational quantum number, which is evidently different from that for higher vibrational levels. This fact can be clearly explained by the dependence of the amount of kinetic energy released to the product degrees of freedom on the initial vibrational state. © 1997 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 48
    Electronic Resource
    Electronic Resource
    Hexabromotricyclobutabenzene and Hexabromohexaradialene: Their Nickel-Mediated One-Pot Syntheses and Crystal Structure (1997)
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 3 (1997), S. 208-210 
    Details
    ISSN: 0947-6539
    Keywords: crystal structure ; cyclobutenes ; nickel ; radialenes ; radical reactions ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of hexakis(dibromomethyl)benzene with [(Bu3P)2-Ni(COD)] (COD = 1,5-cyclooctadiene) in DMF at 65-70°C yielded a mixture of the title compounds. The mixture was separated by column chromatography to yield hexabromotricyclobutabenzene (3 a) and hexabromohexaradialene (4) in 24 and 16% yields, respectively. 1H and 13C NMR spectroscopy suggest that 3 is obtained as the syn-all-trans isomer 3 a, and the symmetric anti-all-trans isomer 3 b is not obtained at all. The X-ray structures of 3 a and 4 are reported. The hexaradialene 4 has a chair conformation, and deviates from planarity by 43.6°. Heat or radical impurities cause the clean transformation of 3 a to 4.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chem.19970030207
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 49
    Electronic Resource
    Electronic Resource
    Metal-Template Electrophilic Substitution on Phenols: Synthesis and Crystal Structure of Bromomagnesium Phenolate and Its Reactive Complex with para-IsopropylbenzaldehydeDedicated to the memory of Professor Giuseppe Casnati on the 4th anniversary of his death (1997)
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 3 (1997), S. 1269-1272 
    Details
    ISSN: 0947-6539
    Keywords: crystal structure ; electrophilic aromatic substitutions ; magnesium ; regioselectivity ; template synthesis ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The crystal structures of the bromomagnesium phenolate 5 and its complex 7 with para-isopropylbenzaldehyde are reported; for the first time it has been possible to demonstrate that the reactive complex 7, responsible for the complete ortho-regioselective control in the alkylation of phenoxymagnesium bromides with aldehydes, is not obtained by simple replacement of the ethereal ligand but by expansion of the metal coordination sphere from 4 (usual tetrahedral configuration) to 5. We infer from 1H NMR studies that the magnesium coordination of complex 7 in solution is analogous to that shown in the solid state, with a complexed ethereal molecule.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chem.19970030814
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 50
    Electronic Resource
    Electronic Resource
    Two New Closely Related MoV Hydroxymonophosphates Built Up of Cd[Mo6P4O25(OH)6]2 And Cd[Mo6P4O26(OH)5]2 ClustersDedicated to Professor H. G. von Schnering on the occasion of his retirement (1997)
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 3 (1997), S. 1797-1800 
    Details
    ISSN: 0947-6539
    Keywords: cadmium ; crystal structure ; hydrothermal synthesis ; hydroxyphosphate ; molybdenum ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two new molybdenum(v) hydroxyphosphates have been synthesized hydrothermally, Na2Cd3(Mo2O4OH)6-(PO4)2(PO3OH)6[N(CH3)4]4·10H20 (1) and Cd9(Mo2O4OH)12(PO4)6(PO3OH)10-[N(CH3)4]8·15H2O (2). Their structures have been determined from single-crystal X-ray diffraction. The water molecules and hydroxyl groups have been deduced from valence calculations. Both compounds crystallize in the triclinic space group P1, with the cell parameters for 1 a = 12.340(2), b = 12.596(1), c = 14.717(2) Å, α = 107.24(1)°, β = 89.83(1)°, γ = 114.31(1)°, V = 1972.3(4) Å3, and for 2 a = 11.942(1), b = 13.339(2), c = 26.765(3) Å, α = 85.33(1)°, β = 86.87(1)°, γ = 64.08(1)°, V = 3821.3(9) Å3. The two frameworks can be described on the basis of similar [Mo6P4X31]n- (X = O, OH) anionic clusters, but 1 is a tridimensional structure, whereas 2 exhibits a monodimensional structure.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chem.19970031111
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 51
    Electronic Resource
    Electronic Resource
    Resonances and antibound states in a Morse potential (1997)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 62 (1997), S. 239-244 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We calculate the resonant and antibound state energies for a Morse potential with a centrifugal barrier using Siegert boundary conditions. Starting with a complex wave number k (purely imaginary for bound and antibound states), we integrate numerically from the origin up to a matching point using Numerov's method. The inward integration is performed using the corresponding (first-order) Riccati equation. The complex eigenvalues are found by matching the two logarithmic derivatives. We find narrow shape resonances within the well, above the dissociation limit, and broad resonances above the centrifugal barrier. Antibound states are found even with J = 0. © 1997 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 52
    Electronic Resource
    Electronic Resource
    A study of methanetetraol dehydration to carbonic acid (1997)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 62 (1997), S. 315-322 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two alternative dehydration reactions C(OH)4 → (HO)2CO + H2O and C(OH)4 + H2O → (HO)2CO + 2H2O are studied by ab initio Becke3LYP/6-311 + G** and MP2/6-31G** methods. Calculated energy and geometry characteristics of intermediates and transition states predict a catalytic effect of one water molecule and the exothermism of the transformations. Relevant HF/6-311 + G**, HF/6-31G**, HF/6-31G, and HF/3-21G calculations were performed for comparison. © 1997 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 53
    Electronic Resource
    Electronic Resource
    Generalized relativistic effective core potential: Gaussian expansions of potentials and pseudospinors for atoms Hg through Rn (1997)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 63 (1997), S. 1107-1122 
    Details
    ISSN: 0020-7608
    Keywords: relativistic pseudopotentials ; heavy atoms ; method of molecular calculation ; electronic structure ; Gaussian approximation ; Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Gaussian expansions of the generalized relativistic effective core potential (GRECP) components are reported for elements Hg through Rn. The accuracy of the analytical GRECPs is estimated by calculations of atomic transition energies with the numerical one-configurational wave functions in comparison with Dirac-Fock calculations. The results of the corresponding calculations with the RECPs of other groups are also given. An “averaged error” in the reproduction of the transition energies without the change of the occupation number of the 5d-shell is an order of magnitude smaller than that for the RECPs of other groups. As is demonstrated for the transitions with the change of the occupation number of the 5d-shell in mercury, the largest absolute error of the GRECP is only 1.5-2 times smaller than that of the energy-adjusted pseudopotential (PP) or the RECP of Ross et al. with the same space of explicitly treated electrons. However, the dispersion of these errors is 19⋅10-4 au for the energy-adjusted PP, 35⋅10-4 au for the RECP of Ross et al. and only 4⋅10-4 au for the GRECP. One-configurational spin-averaged calculations of the molecular properties for HgH and HgH+ are carried out and compared with the corresponding results of Häussermann et al.   © 1997 John Wiley & Sons, Inc. Int J Quant Chem 63: 1107-1122, 1997
    Additional Material: 17 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 54
    Electronic Resource
    Electronic Resource
    Structural transformation of ultra-high modulus and molecular weight polyethylene fibers by high-temperature wide-angle X-ray diffraction (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 35 (1997), S. 623-630 
    Details
    ISSN: 0887-6266
    Keywords: ultra-high modulus and molecular weight polyethylene fibers (UHM-WPE) ; high-temperature wide-angle x-ray diffraction (HTWAXD) ; crystal structure ; orthorhombic/monoclinic/pseudohexagonal transformation ; annealing and thermal behavior ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Wide-angle x-ray diffraction (WAXD) of the ultra-high modulus and molecular weight polyethylene (UHMWPE) fibers at room temperature shows a predominantly orthorhombic structure with trace amount of nonorthorhombic crystals and very low amorphous contents. The calculated unit cell dimensions a and b of the orthorhombic crystals are 7.36 (±0.04) Å, and 4.89 (±0.04) Å, respectively. The apparent crystallite sizes perpendicular to the orthorhombic 110 and 200 reflection planes are 169.8 and 143.4 Å, respectively. The crystallite size perpendicular to the nonorthorhombic 010 reflection is 149.4 Å. The crystal density is calculated to be 1.02 g/cc. With increasing temperature, the thermal expansion coefficient in the a direction is much higher than that in the b direction which explains the structural transformation from the orthorhombic crystals to a pseudohexagonal form. Tension along the fiber axis while being heated during the high-temperature x-ray diffraction (HTWAXD) scanning has shown enhanced structural transformation from the orthorhombic form to the monoclinic form. Structural transformation from the orthorhombic form to the pseudohexagonal phase is not observed on the UHMWPE fibers under axial tension or annealing conditions in HTWAXD. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys, 35: 623-630, 1997
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 55
    Electronic Resource
    Electronic Resource
    Crystalline structure of poly(methyl-n-propylsilane) (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 35 (1997), S. 1533-1543 
    Details
    ISSN: 0887-6266
    Keywords: polysilane ; lamellar microstructure ; crystal structure ; crystallization kinetics ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The thermal behavior and physical structure of atactic poly(methyl-n-propylsilane) (PMPrS) have been investigated by complementary techniques. Temperature-dependent wide-angle X-ray scattering as well as thermal analysis clearly indicate that atactic PMPrS crystallizes below 40°C in a monoclinic lattice with PMPrS adopting an all-trans planar zigzag conformation. Above 40°C, the polymer is in the isotropic amorphous state. A restricted analysis of the structure factors of PMPrS has been performed, indicating that the zigzag planes most probably lie in (110) planes. The chains pack with little interpenetration, and the crystals may be considered as bundles of long, closely packed prisms. The restricted interlocking of neighboring chains results, in turn, in a poor register of the chains along the c-axis. Moreover, transmission electron microscopy reveals that the crystallized polymer adopts a lamellar microstructure, with parallel lamellae tending to form tight bundles. Both electron microscopy and small-angle X-ray scattering indicate crystal thicknesses of about 60 Å. Finally, PMPrS was found to crystallize with a nucleation-controlled type of kinetics. Avrami exponents were calculated as n ≈ 1, suggesting a fibrillar growth geometry compatible with the absence of spherulitic superstructure. A double-melting behavior is also observed for PMPrS. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 1533-1543, 1997
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 56
    Electronic Resource
    Electronic Resource
    Electron diffraction and computer modeling of poly(naphthalic anhydride) crystal structure (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 35 (1997), S. 1575-1588 
    Details
    ISSN: 0887-6266
    Keywords: poly(naphthalic anhydride) ; crystal structure ; electron diffraction ; confined thin film melt polymerization ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Single crystals of poly(naphthalic anhydride) (PNA) have been grown using our confined thin film melt polymerization technique. Lamellae, 70-100 Å thick, are found for the crystals polymerized at 180°C with thinner lamellae for a 200°C polymerization temperature. In addition, irregular lath-shaped crystals are found for both polymerization temperatures, apparently formed by a solid-state polymerization process within the original needle-like monomer crystals. The crystal structure of PNA has been studied by electron diffraction (ED) and computer modeling based on seven different zonal ED patterns. It is found that, in most cases, two or three different zonal patterns are superimposed with a common plane, suggesting variable chain tilting even in individual lamellae. Shearing of the material shortly after the initiation of polymerization, permitted obtaining an additional [010] zone ED pattern. A monoclinic unit cell with one chain, two repeat units is proposed based on measurements of 21 independent reflections; the space group is Pc11; a = 6.26 Å, b = 4.33 Å, c = 18.60 Å, and α = 122.5°. The computer-simulated (Cerius2) molecular conformation and chain packing are described with the corresponding simulated electron diffraction patterns being in good agreement with the observed ones. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 1575-1588, 1997
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 57
    Electronic Resource
    Electronic Resource
    A study of the dilation of the unit cell of metallocene isotactic poly(propylenes): The monoclinic form (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 35 (1997), S. 2511-2521 
    Details
    ISSN: 0887-6266
    Keywords: isotactic poly(propylenes) ; unit-cell density ; crystal structure ; unit-cell parameters ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The lattice parameters of a series of monoclinic metallocene poly(propylenes) of constant molecular weight are measured as a function of defect content, that vary between 0.3 and 2.35 total defects per 100 monomeric units. The parameters are also measured as a function of molecular weight for a fixed defect content and as a function of the crystallization temperature. The b axis is found to increase with decreasing isothermal crystallization temperature whereas only small changes are found for samples rapidly crystallized. The a and c axis showed basically no variation with crystallization temperature. The parameters of the unit cell were essentially constant with varying defect content in the poly(propylene) chain. Lack of observed effect on the dilation of the unit cell by increasing defects is a consequence of the rapid crystallization required to ensure formation of monoclinic crystals. The unit cell parameters increased as a mild function of the molecular weight. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 2511-2521, 1997
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 58
    Electronic Resource
    Electronic Resource
    Morphology, crystal structure, and orientation of poly-p-oxybenzoate on mica (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 35 (1997), S. 1807-1820 
    Details
    ISSN: 0887-6266
    Keywords: poly(p-oxybenzoate) ; confined thin film melt polymerization ; epitaxy ; mica substrate ; morphology ; crystal structure ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polymerization of p-acetoxybenzoic acid between mica sheets, from both the melt and dilute solution, in a wide range of polymerization temperatures (180-400°C) yields an epitaxial-like overgrowth of PpOBA on the mica cleavage surface. The PpOBA overgrowth forms long rows by lateral aggregation of ribbon crystals situated in three substrate directions rotated by 60°. The c-axes of the PpOBA phase I and II lattices are parallel to the 001 plane of the mica, coinciding with the a-axes of the mica hexagonal structure. The aI- and bII-axes lie predominantly on the mica surface. The surface-orienting effect is tentatively attributed to surface steps and or/polar effects; lattice matching does not occur. The recrystallization of bulk polymer samples previously prepared also leads to ordering between mica like that in melt or solution polymerization. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 1807-1820, 1997
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 59
    Electronic Resource
    Electronic Resource
    Synthesis, conformation, and biological activity of two fMLP-OMe analogues containing the new 2-[2′-(methylthio) ethyl] methionine residue (1997)
    New York : Wiley-Blackwell
    Biopolymers 42 (1997), S. 415-426 
    Details
    ISSN: 0006-3525
    Keywords: chemotaxis ; conformation ; crystal structure ; Cα-tetrasubstituted amino acids ; formylpeptides ; 2-[2′-(methylthio)ethyl]methionine ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The new Cα-tetrasubstituted α-amino acid residue 2-[2′-(methylthio) ethyl]methionine (Dmt) has been introduced into the reference chemotactic tripeptide HCO-Met-Leu-Phe-OMe (fMLP-OMe) in place of the leucine or methionine, respectively. The biological activity of the new analogues [Dmt2] fMLP-OMe (2) and [Dmt1] fMLP-OMe (3) has been determined; whereas 2 is active toward human neutrophils, stimulating directed migration, superoxide anion generation, and lysozyme release, 3 results practically inactive in all tested assays. A conformational analysis on 2 and 3 has been performed in solution by using ir absorption and 1H-nmr. The conformation of 2 was also examined in the crystal by x-ray diffraction methods. Both 2 and 3 adopt fully extended conformation in correspondence with the Dmt residue. Biological and conformational results are discussed and compared with related previously studied models. © 1997 John Wiley & Sons, Inc. Biopoly 42: 415-426, 1997
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 60
    Electronic Resource
    Electronic Resource
    RNA crystallography (1997)
    New York : Wiley-Blackwell
    Biopolymers 44 (1997), S. 3-21 
    Details
    ISSN: 0006-3525
    Keywords: RNA ; x-ray crystallography ; crystal structure ; transfer RNA ; ribozyme ; catalytic RNA ; internal loop ; review ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The current state of three-dimensional structure analysis of RNA by x-ray crystallograpy is summarized. The methods of sample preparation, crystallization, data collection, and structure solution are discussed, followed by a review of the RNA structures that have been determined and of common structural features, and finally, an appraisal of future prospects for x-ray crystal structure analysis of RNA. © 1997 John Wiley & Sons, Inc. Biopoly 44: 3-21, 1997
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 61
    Electronic Resource
    Electronic Resource
    Role of two consecutive α,β-dehydrophenylalanines in peptide structure: Crystal and molecular structure of Boc-Leu-ΔPhe-ΔPhe-Ala-Phe-NHMe (1997)
    New York : Wiley-Blackwell
    Biopolymers 42 (1997), S. 373-382 
    Details
    ISSN: 0006-3525
    Keywords: x-ray diffraction ; crystal structure ; dehydrophenylalanine ; constrained peptides ; 310-helix ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An Nα-protected model pentapeptide containing two consecutive ΔPhe residues, Boc-Leu-ΔPhe-ΔPhe-Ala-Phe-NHMe, has been synthesized by solution methods and fully characterized. 1H-nmr studies provided evidence for the occurrence of a significant population of a conformer having three consecutive, intramolecularly H-bonded β-bends in solution. The solid state structure has been determined by x-ray diffraction methods. The crystals grown from aqueous methanol are orthorhombic, space group P212121, a = 11.503(2), b = 16.554(2), c = 22.107(3) Å, V = 4209(1) Å,3 and Z = 4. The x-ray data were collected on a CAD4 diffractometer using CuKa radiation (λ = 1.5418 Å). The structure was determined using direct methods and refined by full-matrix least-squares procedure. The R factor is 5.3%. The molecule is characterized by a right handed 310-helical conformation (〈φ〉 = -68.2°, 〈ψ〉 = -26.3°), which is made up of two consecutive type III β-bends and one type I β-bend. In the solid state the helical molecules are aligned head-to-tail, thus forming long rod like structures. A comparison with other peptide structures containing consecutive ΔPhe residues is also provided. The present study confirms that the -ΔPhe-ΔPhe-sequence can be accommodated in helical structures. © 1997 John Wiley & Sons, Inc. Biopoly 42: 373-382, 1997
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 62
    Electronic Resource
    Electronic Resource
    Thia- und Selena-arachno-undecaboran 6,7-μ-(CH3E)B10H13 Kristallstruktur von arachno-6,7-μ-(CH3Se)B10H13 Theoretische Untersuchungen der Molekülstrukturen und 11B-NMR-Verschiebungen von arachno-6,7-μ-(CH3E)B10H13 (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1157-1162 
    Details
    ISSN: 0044-2313
    Keywords: Thia- and selena-arachno-undecaborane ; preparation ; spectroscopy ; ab initio/IGLO ; GIAO/NMR method ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Thia- and Selena-arachno-undecaborane 6,7-μ-(CH3E)B10H13. Crystal Structure of arachno-6,7-μ-(CH3Se)B10H13. Theoretical Investigations of the Molecular Structures and 11B NMR Shifts of arachno-6,7-μ-(CH3E)B10H13The reaction of B10H14 with (CH3)2S yields with loss of H2 the base adduct 6,9-[(CH3)2S]2B10H12. Although an analogous reaction between B10H14 with disulfanes or diselenanes was expected to produce 6,9 bridged dichalcogen derivatives, (CH3)2S2 failed to react even under reflux conditions. Trisulfane (CH3)2S3 does react, but the pathway is different and leads to (CH3S)B10H13 2 without loss of H2. Unlike of (CH3)2S2, (CH3)2Se2 yields (CH3Se)B10H13, 3. Both 2 and 3 are formed by substitution of a bridging hydrogen and could be obtained in pure form and characterized 11B NMR spectroscopically. A single crystal X-ray structure analysis also was performed on 3 (space group P21/c). The molecular structures of 2 and 3 were optimized at the MP2 level and 11B NMR shifts were computed at the IGLO-SCF, GIAO-SCF and GIAO-B3LYP levels of theory.
    Notes: Bei der Reaktion zwischen B10H14 und (CH3)2S erfolgt unter H2-Abspaltung eine zweifache Adduktbildung, die zu 6,9-[(CH3)2S]2B10H12 führt. Die analoge Umsetzung zwischen B10H14 mit Disulfanen bzw. Diselenanen führte jedoch nicht zu den 6,9-Dichalkogen-verbrückten Derivaten. Bei der Umsetzung mit (CH3)2S2 findet selbst unter Refluxbedingungen keine Reaktion statt, wohl aber mit dem Trisulfan (CH3)2S3. Die Reaktion verläuft aber nicht unter H2-Abspaltung. Vielmehr wird dabei ein Brücken-H-Atom durch eine CH3S-Gruppe substituiert unter Bildung von (CH3S)B10H13 2. Im Gegensatz zu (CH3)2S2 findet aber mit (CH3)2Se2 ebenfalls eine Brücken-H-Substitution statt, wobei (CH3Se)B10H13 3 gebildet wird. 2 und 3 konnten in reiner Form isoliert und 11B-NMR-spektroskopisch charakterisiert werden. Von 3 wurde eine Röntgenstrukturanalyse durchgeführt (Raumgruppe P21/c) und von 2 und 3 die Molekülstrukturen auf MP2-Niveau optimiert sowie 11B-NMR- Verschiebungen mit IGLO-SCF, GIAO-SCF und GIAO-B3LYP berechnet.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976230725
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 63
    Electronic Resource
    Electronic Resource
    Zur Kristallstruktur von CaZn2(OH)6 · 2 H2O (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1287-1289 
    Details
    ISSN: 0044-2313
    Keywords: Calcium hexahydroxodizincate dihydrate ; synthesis ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Crystal Structure of CaZn2(OH)6 · 2 H2OThe electrochemical oxidation of zinc in a zinc/iron-pair leads in an aqueous NH3 solution of calciumhydroxide at room temperature to colourless crystals of CaZn2(OH)6 · 2 H2O. The X-ray structure determination was now successful including all hydrogen positions.P21/c, Z = 2, a = 6.372(1) Å, b = 10.940(2) Å, c = 5.749(2) Å, β = 101.94(2)° N(F2o ≥ 3σF2o) = 809, N(Var.) = 69, R/RW = 0.011/0.012The compound CaZn2(OH)6 · 2H2O contains Zn2+ in tetrahedral coordination by OH- and Ca2+ in octahedral coordination by four OH- and two H2O. The tetrahedra around Zn2+ form corner sharing chains, three-dimensionally linked by isolated polyhedra around Ca2+. Weak hydrogen bridge bonds result between H2O as donor and OH-.
    Notes: Die elektrochemische Oxidation von Zink in einem Zink/Eisen-Paar führt in einer wäßrigen NH3-Lösung von Calciumhydroxid bei Raumtemperatur zu farblosen Kristallen von CaZn2(OH)6 · 2 H2O. An ihnen wurde röntgenographisch die Struktur jetzt einschließlich aller H-Lagen bestimmt.P21/c, Z = 2, a = 6,372(1) Å, b = 10,940(2) Å, c = 5,749(2) Å, β = 101,94(2)° Z(F2o ≥ 3σF2o) = 809, Z(Var.) = 69, R/RW = 0,011/0,012In CaZn2(OH)6 · 2 H2O ist Zn2+ tetraedrisch von OH- und Ca2+ oktaedrisch von vier OH- und zwei H2O umgeben. Die Tetraeder um Zn2+ bilden Ketten über gemeinsame Ecken, die durch voneinander isolierten Oktaedern um Ca2+ dreidimensional verknüpft werden. Es liegen schwache H-Brückenbindungen von H2O als Donator zu OH- vor.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976230819
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 64
    Electronic Resource
    Electronic Resource
    Pseudoelementverbindungen. XI. [1] Untersuchungen zum Komplexbildungsverhalten von Cyanamidonitrat [NO2NCN]-Professor Wolfgang Beck zum 65. Geburtstag gewidmet (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1299-1305 
    Details
    ISSN: 0044-2313
    Keywords: Pseudoelement compounds ; cyanamidonitrate ; copper(I) ; silver(I) ; platinum(II) ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Pseudoelement Compounds. XI. [1] Investigations on the Coordination Behaviour of Cyanamidonitrate [NO2NCN]-With the ionic, potentially ambidentate ligand cyanamidonitrate complexes of the types [MX(PPh3)3], [MX(PPh3)2]2 (M=CuI, AgI) and trans-[Pt(H)X(PPh3)2] (X-=[NO2NCN]-) are introduced. The new compounds are characterized by 1H NMR, 31P NMR, and IR spectroscopy. The crystal structures of [Cu(NO2NCN)(PPh3)2]2 and [Ag(NO2NCN)(PPh3)2]2 are reported. In the complexes [MX(PPh3)3] and trans-[Pt(H)X(PPh3)2] cyanamidonitrate is unidentately coordinated through the nitrile group end-on. In the dimeric complexes [MX(PPh3)2]2 the anion acts bidentately as a bridging ligand. Surprisingly, both coordinative bonds are formed through nitrogen atoms of the NCN group.
    Notes: Es werden mit dem ionischen, potentiell ambidenten Liganden Cyanamidonitrat Komplexe der Typen [MX(PPh3)3], [MX(PPh3)2]2 (M=CuI, AgI) sowie trans-[Pt(H)X(PPh3)2] (X-=[NO2NCN]-) vorgestellt. Die Verbindungen wurden 1H-NMR-, 31P-NMR- und IR-spektroskopisch charakterisiert. Für [Cu(NO2NCN)(PPh3)2]2 und [Ag(NO2NCN)(PPh3)2]2 liegen Kristallstrukturanalysen vor.Cyanamidonitrat wird in den Komplexen [MX(PPh3)3] und trans-[Pt(H)X(PPh3)2] einzähnig über das endständige N-Atom der Nitrilgruppe koordiniert. In den dimeren Komplexen [MX(PPh3)2]2 liegt das Anion als zweizähniger Brükkenligand vor. Überraschend werden beide koordinativen Bindungen über die Stickstoffatome der NCN-Gruppe ausgebildet.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976230821
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 65
    Electronic Resource
    Electronic Resource
    Kristallstruktur der Tieftemperaturmodifikation von RuTe2 (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1657-1660 
    Details
    ISSN: 0044-2313
    Keywords: Ruthenium ; chalcogenide ; chemical transport ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Crystal Structure of the Low Temperature Modification of RuTe2Black shining, platelet like single crystals of α-RuTe2 were obtained by chemical transport reaction with Cl2/AlCl3 (crystal dimensions up to 1 mm). The crystal structure of this low temperature modification of α-RuTe2 hitherto only known from powder measurements, was redetermined at room temperature by single crystal X-ray diffraction on a four-circle diffractometer. α-RuTe2 crystallizes in the marcasit structure typ in the orthorhombic spacegroup Pnnm (No. 58) with the lattice constants a = 528.12(13), b = 639.43(19), c = 400.85(13) pm.
    Notes: Durch chemischen Transport mit dem Transportmittel Cl2/AlCl3 konnten schwarzglänzende, plattenartige Einkristalle von α-RuTe2 erhalten werden (Kantenlänge bis zu 1 mm). Die Kristallstruktur dieser bisher nur aus Pulverdaten bekannten Tieftemperaturmodifikation von RuTe2 wurde röntgenographisch an einem Einkristall auf einem Vierkreisdiffraktometer bei Raumtemperatur neu bestimmt. α-RuTe2 kristallisiert im Markasit-Strukturtyp in der orthorhombischen Raumgruppe Pnnm (Nr. 58) mit den Gitterkonstanten a = 528,12(13), b = 639,43(19), c = 400,85(13) pm.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976231029
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 66
    Electronic Resource
    Electronic Resource
    Mesityloxomolybdän- und -wolfram-Verbindungen. I. Die Struktur von LiMoO2Me2Mes(OEt2)2 (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1661-1664 
    Details
    ISSN: 0044-2313
    Keywords: Organo molybdenum compounds ; oxo complexes ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Mesityl Oxo Molybdenum and Tungsten Compounds. I. Structure of LiMoO2Me2Mes(OEt2)2LiMoO2Me2Mes(OEt2)2 2 is prepared by literature method [2] from MoO2Mes2 1 and LiMe. Its x-ray structure and NMR-spectral data are presented. 2 adopts a dimer structure in which two [MoO2Me2Mes]- anions are linked via two bridging [Li(OEt2)2]+ cations bonded to the oxo ligands. The resulting [‥OMoOLi‥]2 ring is planar.
    Notes: Die Struktur der bekannten, aus MoO2Mes2 1 und LiMe dargestellten Verbindung LiMoO2Me2Mes(OEt2)2 2 [2] sowie ihre NMR-spektroskopischen Daten werden mitgeteilt. 2 bildet ein in der Raumgruppe P1 kristallisierendes Dimer durch Verknüpfung zweier [MoO2Me2Mes]--Anionen über Oxo-Liganden durch zwei Kationen [Li(OEt2)2]+. Der gebildete [‥OMoOLi‥]2- Achtring ist eben.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976231030
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 67
    Electronic Resource
    Electronic Resource
    Über den Einfluß von Temperatur, Druck und Substitution auf die Kristallstruktur von ARh2P2 (A = Ca, Sr, Eu, Ba)Professor Welf Bronger zum 65. Geburtstag gewidmet (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1418-1424 
    Details
    ISSN: 0044-2313
    Keywords: Ternary Rhodium phosphides ; crystal structure ; phase transition ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: About the Effect of Temperature, Pressure, and Substitution on the Crystal Structure of ARh2P2 (A = Ca, Sr, Eu, Ba)Four compounds ARh2P2 (A = Ca, Sr, Eu, Ba) were prepared by heating mixtures of the elements and investigated by means of single crystal X-ray methods. They crystallize in the ThCr2Si2 type structure (I4/mmm; Z = 2) with P—P distances along [001] reaching from 2.26 Å (CaRh2P2) to 3.74 Å (BaRh2P2). With increasing temperature (EuRh2P2) or increasing pressure (SrRh2P2) a first order phase transition occurs with strong changes of the P—P distances. Substitution of the atoms changes the bond lengths of the compounds too.
    Notes: Vier Verbindungen ARh2P2 (A = Ca, Sr, Eu, Ba) wurden durch Erhitzen entsprechender Elementgemenge dargestellt und hinsichtlich ihrer Kristallstruktur mit Hilfe von Einkristallmethoden charakterisiert. Sie kristallisieren in der tetragonalen ThCr2Si2-Struktur (I4/mmm; Z = 2) und unterscheiden sich im wesentlichen durch ihre P—P-Abstände längs [001]. Diese reichen von 2,26 Å bei CaRh2P2 bis 3,74 Å bei BaRh2P2 und verändern sich drastisch im Zuge von Phasenumwandlungen 1. Ordnung durch Temperaturerhöhung bei EuRh2P2 sowie unter erhöhtem Druck bei SrRh2P2. Substitution übt ebenfalls einen großen Einfluß auf den Strukturfeinbau der Verbindungen aus.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976230917
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 68
    Electronic Resource
    Electronic Resource
    Zur Kristallstruktur von Tb2Se3 (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1744-1746 
    Details
    ISSN: 0044-2313
    Keywords: Terbium sesquiselenide ; chemical transport ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Crystal Structure of Tb2Se3Single crystals of Tb2Se3 could be prepared by chemical transport reaction with AlCl3. By starting from TbSe1.9 and terbium metal black needles of Tb2Se3 in the U2S3 type structure with the space group Pnma and a = 1113,0(1) pm, b = 402,4(1) pm and c = 1095,1(3) pm were obtained.
    Notes: Einkristalle von Tb2Se3 konnten durch chemischen Transport mit AlCl3 dargestellt werden. Ausgehend von pulverförmigem TbSe1,9 und Terbiummetall wurden schwarze, nadelförmige Einkristalle von Tb2Se3 im U2S3-Strukturtyp mit der Raumgruppe Pnma und a = 1113,0(1) pm, b = 402,4(1) pm und c = 1095,1(3) pm erhalten.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976231113
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 69
    Electronic Resource
    Electronic Resource
    Nitridsulfidchloride der Lanthanide: III. Synthese und Kristallstruktur von Pr5N3S2Cl2Professor Rudolf Hoppe zum 75. Geburtstag gewidmet (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1747-1752 
    Details
    ISSN: 0044-2313
    Keywords: Lanthanides ; nitride sulfide chlorides ; Pr5N3S2Cl2 ; synthesis ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Nitride Sulfide Chlorides of the Lanthanides. III. Synthesis and Crystal Structure of Pr5N3S2Cl2By reacting praseodymium with sulfur, sodium azide and praseodymium trichloride in sealed, evacuated silica tubes (850°C, 7 d), the nitride sulfide chloride Pr5N3S2Cl2 is obtained in case of a 4:2:1:1 molar ratio of the reactants (Pr:S:NaN3:PrCl3). A slight excess of trichloride or the addition of NaCl as a flux supports the yield of brownish red, rod-shaped transparent crystals which prove to be stable against hydrolysis. The crystal structure (monoclinic, C2/m (no. 12), a = 1540.2(1), b = 400.92(3), c = 1656.3(1) pm, β = 101.24(1)°, Z = 4, R = 0.039, Rw = 0.028) was determined by means of X-ray single crystal data. Thus five crystallographically different cations (Pr3+) are present which with three distinct kinds of nitride anions (N3-) build up two types of translationally commensurate chains from interconnected [NPr4] tetrahedra. With an additional edge per “chain-link” in chain I, two single chains ∞1[NPr3/3ePr1/1t]3+ (≡∞1[NPr2]3+) of cis-edge connected [NPr4] tetrahedra (known from the Sm4N2S3-type structure) are condensed into the double chain ∞1[(N1){(Pr1)(2+2)/(2+2)e,e(Pr2)(2+1)/(2+1)e,v}(N2)(Pr3)1/1t]3+ (≡∞1[N2Pr3]3+). Chain II consists of two single chains ∞1[NPr2/2vPr2/1t] 6+ (≡∞1[NPr3]6+) of vertex-connected [NPr4] tetrahedra (known from the Sm3NS3-type structure), which are condensed to the double chain ∞1[(N3)(Pr4)2/2e(Pr5)2/2v]3+ (≡∞1[NPr2]3+) via an additional edge per “chain-link” too. Both types of chains are bundled along [010] like a closest packing of rods. Four crystallographically different but by X-ray diffraction indistinguishable anions S2- and Cl- hold both cationic double chains together and also adjust the charge balance in a molar ratio of 1 : 1.
    Notes: Durch Umsetzung von Praseodym mit Schwefel, Natriumazid und Praseodymtrichlorid in evakuierten Quarzglasampullen (850°C, 7 d) wird bei molaren Verhältnissen der Edukte (Pr:S:NaN3:PrCl3) von 4:2:1:1 das Nitridsulfidchlorid Pr5N3S2Cl2 erhalten. Ein geringer Überschuß an Trichlorid oder der Zusatz von NaCl als Flußmittel fördert die Bildung von braunroten, stäbchenförmigen, transparenten Kristallen, die sich als unempfindlich gegenüber Hydrolyse erweisen. Die Kristallstruktur (monoklin, C2/m (Nr. 12); a = 1540,2(1); b = 400,92(3); c = 1656,3(1) pm; β = 101,24(1)°, Z = 4; R = 0,039; Rw = 0,028) wurde röntgenographisch anhand von Einkristalldaten bestimmt. Danach liegen fünf kristallographisch unterschiedliche Kationen. (Pr3+) vor, die mit drei verschiedenen Sorten von Nitridionen (N3-) zwei Typen translationskommensurabler Stränge aus verknüpften [NPr4]-Tetraedern bilden. In Strang I werden zwei Einfachketten ∞1[NPr3/3kPr1/1t]3+ (≡∞1[NPr2]3+) cis-kantenverknüpfter [NPr4]-Tetraeder (bekannt aus der Sm4N2S3-Struktur) über eine zusätzliche Kante pro „Kettenglied“ zur Doppelkette ∞1[(N1){(Pr1)(2+2)/(2+2)k,k(Pr2)(2+1)/(2+1)k,e}(N2)(Pr3)1/1t]3+ (≡∞1[N2Pr3]3+) verknüpft. Strang II besteht aus zwei Einfachketten ∞1[NPr2/2ePr2/1t]6+ (≡∞1[NPr3]6+) eckenverknüpfter [NPr4]-Tetraeder (bekannt aus der Sm3NS3-Struktur), die über eine zusätzliche Kante pro „Kettenglied“ zur Doppelkette ∞1[(N3)(Pr4)2/2k(Pr5)2/2e]3+ (≡∞1[NPr2]3+) kondensiert sind. Beide Strangsorten ordnen sich längs [010] nach dem Motiv einer dichtesten Stabpackung an. Vier kristallographisch unterschiedliche, röntgenographisch jedoch nicht unterscheidbare Anionen S2- und Cl- sorgen für den Zusammenhalt der kationischen Doppelketten und regeln im molaren Verhältnis von 1 : 1 auch den Ladungsausgleich.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976231114
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 70
    Electronic Resource
    Electronic Resource
    Diorganozinn(IV)-Derivate dreizähniger Dithiocarbazone - Strukturuntersuchungen in Lösung und im festen ZustandProfessor Lothar Beyer zum 60. Geburtstag gewidmet (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 141-146 
    Details
    ISSN: 0044-2313
    Keywords: Diorganotin complexes ; dithiocarbazone complexes ; chelate complexes ; crystal structure ; i.r.-, mass-, multinuclear n.m.r. spectra ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Diorganotin(IV) Derivatives of Tridentate Dithiocarbazones - Structure Determination in the Solid and Liquid StateThe tridentate ligands with the S-Methyldithiocarbazate Schiff Base of 2-Salicylaldehyde (H2Sal) and 2-Pyridinaldehyde (HPyr) react in different way with diorganotin(IV) oxides, in the first case to the five-coordinate complex R2Sn—Sal with trigonal bipyramidal structure and in the second case to the binuclear complex [(R2Sn—Pyr)2CO3] with a bridging carbonat anion. The structures were elucidated by X-ray diffraction and by multinuclear NMR in solution. IR- and Mass-spectrometric measurements complete the results.
    Notes: Die dreizähnigen Liganden S-Methyl-β-N-(2-hydroxyphenyl)-methyliden- (H2Sal) und S-Methyl-β-N-(2-pyridyl)-methyliden-dithiocarbazon (HPyr) reagieren in unterschiedlicher Weise mit Diorganozinn(lV)-oxiden. Mit dem erstgenannten Liganden zu dem fünffach koordinierten Komplex R2Sn—Sal mit trigonal bipyramidaler Struktur, in der Reaktion mit dem zweiten Liganden zu dem Zweikernkomplex [(R2Sn—Pyr)2CO3] mit einem Carbonatanion als Brückenligand. Die Strukturaufklärungen erfolgten mittels Röntgenkristallstrukturanalyse und in Lösung mit multinuklearer NMR-Spektroskopie. IR- und massenspektrometrische Messungen ergänzen die Aussagen.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976230123
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 71
    Electronic Resource
    Electronic Resource
    The Synthesis and Crystal Structure of Hg3TeI4Professor Rudolf Hoppe zum 75. Geburtstag gewidmet (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1843-1846 
    Details
    ISSN: 0044-2313
    Keywords: Mercury iodide telluride ; crystal structure ; ccp anion packing with partially filled tetrahedral holes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthese und Kristallstruktur von Hg3TeI4Die Struktur von kubischem Hg3TeI4 wurde aus Pulverdaten bestimmt. Auf die vier Positionen der kubisch-dichtesten Packung der Anionen sind 0.8 Te-Atome und 3.2 I-Atome statistisch verteilt. Die beiden Sorten von Tetraederlücken sind zu 2/4 bzw. 0.4/4 von Hg-Atomen besetzt. Mit einem Ordnungsmodell niederer Symmetrie kann die stöchiometrische Zusammensetzung erklärt und eine homogene Ladungsverteilung erreicht werden. Das Ordnungsmodell enthält Regionen der Struktur von rotem HgI2, die durch Fragmente vom SiS2-Typ miteinander verbunden sind.
    Notes: The structure of cubic Hg3TeI4 was determined from powder data. The four positions of the cubic closestpacking of the anions are statistically occupied by 0.8 Te-atoms and 3.2 I-atoms. The two types of tetrahedral holes are occupied to the extent of 2/4 and 0.4/4, respectively, by Hg-atoms. With an ordered model of lower symmetry, the stoichiometric composition can be explained and a homogeneous charge distribution can be achieved. The ordered model contains regions of the structure of red HgI2, which are connected by fragments of the SiS2-type.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976231129
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 72
    Electronic Resource
    Electronic Resource
    Crystal Structure of Mixed Crystals of the Tetra(n-butyl)ammonium Salts of cis-Tetrafluorophthalocyaninato(2-)tantalate(V) and cis-Trifluorophthalocyaninato(2-)tantalate(IV) (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1853-1854 
    Details
    ISSN: 0044-2313
    Keywords: Phthalocyaninates ; tantalum compounds ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: cis-Trichlorophthalocyaninato(2-)tantalate(V) reacts with excess tetra(n-butyl)ammonium fluoride trihydrate yielding mixed crystals of the tetra(n-butyl)ammonium salts of cis-tetrafluorophthalocyaninato(2-)tantalate(V) and cis-trifluorophthalocyaninato(2-)tantalate(IV) in the ratio five to four. These crystallize in the monoclinic space group P21/ n with cell parameters: a = 13.368(2) Å, b = 13.787(2) Å, c = 23.069(3) Å, β = 93.35(1)°, Z = 4. Tav is octacoordinated with four F atoms and four Niso atoms in an antiprismatic cis-arrangement. The Tav-F distance varies from 1.919(7) to 1.966(4) Å. TaIV is heptacoordinated with three F atoms in a cis-arrangement. The TaIV-F distance varies from 1.74(1) to 1.966(4) Å. The Ta atom is located out of the centre of the N4 plane towards the F atoms by 1.234(3) Å. The Ta-N distances range from 2.261(6) to 2.310(6) Å.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976231204
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 73
    Electronic Resource
    Electronic Resource
    Reindarstellung und Kristallstruktur von Lithiumnitridhydrid, Li4NH, Li4ND (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1912-1916 
    Details
    ISSN: 0044-2313
    Keywords: Lithium nitride hydride ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and Crystal Structure of Lithium Nitride Hydride, Li4NH, Li4NDSingle phase Li4NH was prepared by the reaction of Li3N and LiH at 490°C. Its structure has been solved from x-ray and time-of-flight neutron powder diffraction data.Li4NH crystallizes in an ordered variant of the Li2O structure. N and H occupy the sites of two interpenetrating “extended” diamond lattices. Li occupies all N2H2 tetrahedral voids and is found to be shifted into a N2H tetrahedral face. As a result H is in compressed tetrahedral coordination by Li, while N is in bisdisphenoidal coordination by Li. Alternatively, the Li4NH structure may be regarded as a [Li4N]+threedimensional net, its voids being filled up with H-.Li4NH is a reactive solid, which decomposes to imide when in contact with N2 or H2 at some 400°C.
    Notes: Li4NH wurde durch Reaktion von Li3N und LiH bei 490°C erhalten. Die vollständige Strukturbestimmung gelang über Röntgen- und Flugzeit-Neutronen-Pulverdiffraktion.Li4NH kristallisiert in einer Ordnungsvariante der Li2O-Struktur (Raumgruppe I41/a, a = 489.18(1), c = 993.21(3) pm, Z = 4). N und H besetzen die Plätze von zwei ineinander gestellten gestreckten Diamantgittern. Li besetzt, in Richtung einer N2H-Dreiecksfläche ausgelenkt, alle N2H2-Tetraederlücken. Als Folge ist H gestaucht tetraedrisch und N verzerrt kubisch von Li koordiniert. Alternativ läßt slch die Struktur der Titelverbindung als ein [Li4N]+-Raumnetz deuten, in dessen Hohlräume zum Ladungsausgleich Hydridionen eingebaut sind.Li4NH reagiert bei höheren Temperaturen mit N2 bzw. H2 unter Imidbildung.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976231215
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 74
    Electronic Resource
    Electronic Resource
    Mg2PN3 und Ca2PN3 - Phosphor(V)-nitride mit eindimensional unendlichen Ketten eckenverknüpfter PN4-Tetraeder (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 69-74 
    Details
    ISSN: 0044-2313
    Keywords: Alkaline earth metals ; phosphorus nitrides ; synthesis ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Mg2PN3 and Ca2PN3 - Phosphorus(V) Nitrides with Infinite Chains of Corner Sharing PN4 TetrahedraMg2PN3 and Ca2PN3 have been synthesized by the reaction of the respective metal nitrides with P3N5 at 800°C. The products have been obtained as fine crystalline powders. The crystal structures have been determined on the basic of powder diffraction data. Mg2PN3 (Cmc21, a = 972,64(8), b = 564,30(5), c = 473,02(2) pm, Z = 4) and Ca2PN3 (Cmca, a = 519,14(4), b = 1031,63(8), c = 1128,8(1) pm, Z = 8) contain Mg2+ and Ca2+ ions, respectively, as well as PN3 Zweier chains of corner sharing PN4 tetrahedra. A significant difference of the stretching factor of the PN3 chains has been observed in Mg2PN3 (fs = 0,88) and Ca2PN3 (fs = 1,0).
    Notes: Mg2PN3 und Ca2PN3 wurden durch Reaktion der jeweiligen Metallnitride mit P3N5 bei 800°C als feinkristalline Pulver erhalten. Ihre Kristallstrukturen wurden aus Pulverdaten bestimmt und verfeinert. Mg2PN3 (Cmc21, a = 972,64(8), b = 564,30(5), c = 473,02(2) pm, Z = 4) und Ca2PN3 (Cmca, a = 519,14(4), b = 1031,63(8), c = 1128,8(1) pm, Z = 8) enthalten im Festkörper Mg2+- bzw. Ca2+-Ionen und PN3-Zweierketten eckenverknüpfter PN4-Tetraeder. Es ergeben sich deutlich unterschiedliche Streckungsfaktoren der PN3-Ketten von fs = 0,88 (Mg2PN3) und fs = 1,0 (Ca2PN3).
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976230112
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 75
    Electronic Resource
    Electronic Resource
    Tetrameres Di(-tert-butylamino)di(-N-lithiummethylamino)silan, (Me3CHN)2Si(NLiMe)2 - Darstellung und KristallstrukturProfessor Peter Sartori zum 65. Geburtstag gewidmet (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 288-291 
    Details
    ISSN: 0044-2313
    Keywords: Tetraaminosilane ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Tetrameric Di(-tert-butylamino)di(-N-lithiomethylamino)silane, (Me3CHN)2Si(NLiMe)2 - Synthesis and Crystal StructureDi(-tert.-butylamino)dichlorosilane reacts with an excess of methylamine to give di(-tert.-butylamino)di(methylamino)silane 1, (Me3CHN)2Si(NHMe)2. The dilithiumderivative 2, (Me3CHN)2Si(NLiMe)2, is obtained in the reaction of 1 with a molar ratio 1:2 of n-buli in n-hexane. In absence of donorsolvents 2 crystallizes tetrameric. Lithium is coordinated in three different ways and substitutes the methylamino-hydrogen. In the crystal structure two eight-membered (NLiNSi)2-rings are connected by two lithium.
    Notes: Di(-tert.-butylamino)dichlorsilan reagiert mit Methylamin im überschuß zu Di(-tert.-butylamino)di(methylamino)silan 1, (Me3CHN)2Si(NHMe)2. Nach Metallierung mit der bimolaren Menge n-BuLi in n-Hexan wird das Lithiumderivat 2, (Me3CHN)2Si(NLiMe)2, gebildet. In Abwesenheit von Donorsolventien kristallisiert 2 aus n-Hexan als Tetramer. Lithium liegt dabei in drei verschiedenen Koordinationen vor und ersetzt den Methylamin-Wasserstoff. Im Kristall werden zwei achtgliedrige (NLiNSi)2 Ringe über zwei Lithiumionen verbunden.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976230146
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 76
    Electronic Resource
    Electronic Resource
    Metallkomplexe mit biologisch wichtigen Liganden. XC. Chirale Cyclopentadienyl-Nitrosyl-Molybdän-Komplexe mit α-Aminocarboxylat-Chelat-Liganden: (η5-C5R5)(ON)(I)Mo(α-Aminocarboxylat) (R = H, Me)Professor Klaus Brodersen zum 70. Geburtstag gewidmet (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 299-303 
    Details
    ISSN: 0044-2313
    Keywords: Cyclopentadienyl nitrosyl molybdenum complexes ; α-aminocarboxylate ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metal Complexes of Biologically Important Ligands. XC [1]. Chiral Cyclopentadienyl-Nitrosyl-Molybdenum Complexes of α-Amino Carboxylates: (η5-C5R5)(ON)(I)Mo(α-aminocarboxylate) (R = H, Me)The reactions of [(η5-C5H5)Mo(NO)I2]2 with glycinate, D-phenylglycinate, L-prolinate and L-azetidine-2-carboxylate give the chiral chelate complexes (η5-C5H5)(ON)(I)Mo(η-aminocarboxylate) as mixtures of isomers. The x-ray diffraction of a crystal of shows trans configuration of the amino acid and nitrosyl donors in a tetragonal pyramid.
    Notes: Die iodoverbrückten Komplexe [(η5-C5H5)Mo(NO)I2]2 setzen sich mit Glycinat, D-Phenylglycinat, L-Prolinat und L-Azetidin-2-carboxylat zu den chiralen Chelat-Komplexen (η5-C5H5)(ON)(I)Mo(α-Aminocarboxylat) um, die als Mischung von Isomeren entstehen. Die Röntgenstrukturanalyse eines Kristalls von zeigt die trans-Konfiguration der Amino- und Nitrosyl-Liganden in einer tetragonalen Pyramide.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976230148
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 77
    Electronic Resource
    Electronic Resource
    Se17[NbCl6]2 und Se17[TaBr6]2 - zwei neue Vertreter des Strukturtyps Se17[MX6]2Professor Joachim Strähle zum 60. Geburtstag gewidmet (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 780-784 
    Details
    ISSN: 0044-2313
    Keywords: Heptadecaselenium(2+) ; Hexachloroniobate(-) ; Hexabromotantalate(-) ; solvothermal reactions ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Se17[NbCl6]2 and Se17[TaBr6]2 - Two New Compounds in the Structure Type Sel7[MX6]2The reaction of Se, SeCl4 and NbCl5 in SnCl4 in a sealed glass ampoule at 150°C yields Se17[NbCl6]2 and from Se, SeBr4 and TaBr5 in SiBr4 under the same conditions Se17[TaBr6]2 is formed. Both compounds crystallize triclinic in form of black moisture sensitive crystals, space group P1, Z = 2 (Se17[NbCl6]2: a = 1322.3(5) pm, b = 1309.0(6) pm, c = 1144.9(4) pm, α = 99.18(3)°, β = 99.55(3)°, γ = 112.17(3)°; Se17[TaBr6]2; 1354.5(7) pm, b = 1346.0(9) pm c = 1179.5(6) pm, α = 99.26(5)°, β = 97.81(4)°, γ = 112.52(5)°). Both are isotypic to the previously reported Se17[WCl6]2. The structures are built of octahedral [NbCl6] and [TaBr6] ions, respectively, and of (Se17)2+ ions The cations consist of two Se7 rings which are connected by a Se3 chain, and thus contain two three-coordinate Se atoms which carry formally the positive charge.
    Notes: Durch solvothermale Reaktion von Se, SeCl4 und NbCl5 in SnCl4 in einer geschlossenen Ampulle bei 150°C entsteht Se17[NbCl6]2 und aus Se, SeBr4 und TaBr5 in SiBr4 unter analogen Bedingungen Se17[TaBr6]2. Beide Verbindungen kristallisieren triklin in Form schwarzer, hydrolyseempfindlicher Kristalle, Raumgruppe P1, Z = 2 (Se17[NbCl6]2: a = 1322,3(5) pm, b = 1309,0(6) pm, c = 1144,9(4) pm, α = 99,18(3)°, β = 99,55(3)°, γ = 112,17(3)°; Se17[TaBr6]2: 1354,5(7) pm, b = 1346,0(9) pm, c = 1179,5(6) pm, α = 99,26(5)° β = 97,81(4)°, γ = 112,52(5)°) und sind isotyp zu Se17[WCl6]2 Die Strukturen sind aus oktaedrischen [NbCl6]- - bzw. [TaBr6]-- und aus (Se17)2+-Ionen aufgebaut, die aus jeweils zwei Se7-Ringen bestehen, die über eine Se3-Brücke verknüpft sind. Jedes Ion enthält zwei dreibindige Se-Atome, die formal die positive Ladung tragen.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.199762301123
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 78
    Electronic Resource
    Electronic Resource
    Darstellung und Kristallstruktur von Diammonium-heptachloropentaoxotriniobat(V) (NH4)2[Nb3O5Cl7]Professor Joachim Strähle zum 61. Geburtstag gewidmet (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 805-809 
    Details
    ISSN: 0044-2313
    Keywords: Diammoniuni heptachloropentaoxotriniobate(V) ; niobiumoxochlorides ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and Crystal Structure of Diammoniuni Heptachloropentaoxotriniobate(V) (NH4)2[Nb3O5Cl7]Colourless sometimes pale blue crystals of (NH4)2[Nb3O5Cl7] are prepared in silica tubes from a mixture of NbCI5, NH4CI and As2O3 at 1050 K. (NH4)2[Nb3O5Cl7] crystallizes in space group C2/c with Z = 4. The lattice constants at 293 K are a = 1680.6(8) pm, b = 886.6(1) pm, c = 1104.3(5) pm and β = 111.35(2)°. The structure consists of layers of [(Nb3O5Cl7)2-]∞2. Within a layer the niobium centered octahedra are corner sharing. The structure of the anion shows a new kind of octahedral connectivity for a layered MX4-structure. The ammonium ions are located in between the polyanionic layers.
    Notes: Man erhält (NH4)2[Nb3O5Cl7] in kristalliner Form in Quarzglasampullen aus NbCl5, NH4Cl und As2O3 bei 1050 K. Die Kristalle sind farblos manchmal blaßblau. (NH4)2[Nb3O5Cl7] kristallisiert bei 293 K monoklin in der Raumgruppe C2/c mit Z = 4 und den Gitterkonstanten a = 1680,6(8) pm, b = 886,6(1) pm, c = 1104,3(5) pm und β = 111,35(2)° Die Struktur besteht aus [(Nb3O5Cl7)2-]∞2-Schichten in denen die Oktaederbasisflächen über Ecken verknüpft sind. Die Struktur des Polyanions zeigt eine neuartige Oktaederverknüpfung für eine MX4-Schichtstruktur. Zwischen diesen Schichten befinden sich die Ammoniumionen.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.199762301127
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 79
    Electronic Resource
    Electronic Resource
    Die Kristallstrukturen von CsBiO2 und Cs3BiO3Professor Joachim Strähle zum 60.Geburtstag gewidmet (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 832-836 
    Details
    ISSN: 0044-2313
    Keywords: Cesiumbismuthate(III) ; synthesis ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Crystal Structures of CsBiO2 and Cs3BiO3CsBiO2 (pale yellow) and Cs3BiO3 (yellow) were obtained by solid state reactions of the binary components Cs2O und Bi2O3 at temperatures of 700°C and 550°C, respectively, The crystal structure of CsBiO2 (C2/c, a = 827.4(2), b = 920.4(2), c = 597.87(9) pm, β = 122.51(1)°, Z = 4, 975 diffractometer data, R1 = 0.058, wR2 = 0.077) contains infinite ∞1[BiO2/2O′2/2] chains. The structure determination of Cs3BiO3 (P213, a = 920,86(8), Z = 4, 289 diffractometer data, R1 = 0,048, wR2 = 0.081) reveals ‘isolated’ BiO33- groups. In this structure the cation arrangement is the same as that of the atoms in the intermetallic phase Cs3Bi.
    Notes: CsBiO2 (hellgelb) und Cs3BiO3 (gelb) wurden durch Festkörperreaktion aus den binären Komponenten Cs2O und Bi2O3 bei Temperaturen von 700°C bzw. 550°C dargestellt. In CsBiO2 liegen nach der Einkristallröntgenstrukturanalyse (C2/c; a = 827,4(2); b = 920,4(2); c = 597,87(9) pm; β = 122,51(1)°; Z = 4; 975 Diffraktometerdaten; R1 = 0,058; wR2 = 0,077) unendlich ausgedehnte ∞1[BiO2/2O′2/2]-Ketten vor. Die Kristallstruktur von Cs3BiO3 (P213; a = 920,86(8) pm; Z = 4; 289 Diffraktometerdaten; R1 = 0,048; wR2 = 0,081) enthält ‚isolierte‘ pyramidale BiO33--Anionen. Die Kationenanordnung in Cs3BiO3 entspricht der Atom-anordnung in der intermetallischen Phase Cs3Bi.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.199762301131
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 80
    Electronic Resource
    Electronic Resource
    The Reaction of P3N3Cl4(NH2)2 with HCl; The Crystal Structure of P3N3Cl5(NH2) (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 637-641 
    Details
    ISSN: 0044-2313
    Keywords: 2-amino-2,4,4,6,6-pentachloro-2λ5,4λ5,6λ5-cyclo-triphosphaza-l,3,5-trien ; 2,4-diamino-4,4,6,6-tetrachloro-2λ5,4λ5,6λ5-cyclotriphosphaza-l,3,5-trien ; 2,4-diamino-4,4,6,6-tetrachloro-2λ5,4λ5,6λ5-cyclotriphosphaza-l,3,5-trien-l-ium-chloride ; preparation ; crystal structure ; molecular structure ; vibrational spectra ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Die Reaktion von P3N3Cl4(NH2)2 mit HCl; Die Kristallstruktur von P3N3Cl5(NH2)P3N3Cl5(NH2) kann in hoher Reinheit und mit guten Ausbeuten durch Reaktion von P3N3Cl4(NH2)2 mit gasförmigem HCI in Acetonitril erhalten werden. Wird, Diethylether oder Dichlormethan als Lösungsmittel verwendet, scheidet sich die salzartige Verbindung [P3N3CI4H(NH2)2]+Cl als mikrokristallines Produkt aus. Die Kristallstruktur von P3N3Cl5(NH2) wurde durch Röntgen Kristallstrukturanalyse untersucht. Schwingungsspektren und thermisches Verhalten sowohl des P3N3Cl5 (NH2) als auch des [P3N3Cl4H(NH2)2]+Cl - werden kurz diskutiert.
    Notes: P3N3Cl5(NH2) in high purity and a good yield can be obtained by the reaction of P3N3Cl4(NH2)2 with gaseous HCl in acetonitrile. If diethylether or dichlormethane is used as a solvent, a salt-like compound [P3N3Cl4H(NH2)2]+Cl - is formed as a microcrystalline product instead of P3N3Cl5(NH2). The crystal structure of P3N3Cl5(NH2) was determined by X-ray structure analysis. Vibrational spectra and thermic behavior of both P3N3Cl5(NH2) and [P3N3Cl4H(NH2)2]+Cl - are also briefly discussed.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.199762301101
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 81
    Electronic Resource
    Electronic Resource
    Crystal, molecular, and electronic structure of Trans-bis[ethanone, 1-(2-hydroxyphenyl)-oximato]Nickel(II) (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 627-632 
    Details
    ISSN: 0044-2313
    Keywords: 2-Hydroxyacetophenoneoxime complex ; nickel complex ; Ni(C8H8NO2)2 ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Kristall-, Molekular- und Elektronenstruktur von Trans-Bis[ethanon,1-(2-hydroxyphenyl)oximato]nickel(II)[Ni(apox)2] (apox = Anion des 2-Hydroxyacetophenonoxims, C8H8NO2-) wurde dargestellt und durch spektroskopische Messungen (IR, 1H NMR, UV-Vis) und theoretische Berechnungen mit der Hückel-Methode untersucht. Die Struktur wurde durch Röntgenstrukturanalyse ermittelt. Elementarzelle: monoklin, Raumgruppe P21/c mit a = 7,845(1), b = 9,911(2), c = 19,371(2)Å, β = 94,37(1)°, Z = 4. Hückel-Rechnungen im Zusammenhang mit dem Elektronenspektrum zeigen, daß die Banden bie 2,73 und 2,62 μm-1 als MLCT und bie 1,62 μm-1 als d-d-Übergang charakterisiert werden können, während die bie 2,14 μm-1 einen gemischten Charakter von MLCT und d-d-Übergang aufweist.
    Notes: The compound [Ni(apox)2], (where apox - denotes the anion of 2-hydroxyacetophenoneoxime, C8H8NO2-), was prepared and studied by means of spectroscopic (IR, 1H NMR, UV-Vis) measurements and theoretical calculations employing the Hückel method. The structure was determined by X-ray diffraction studies. The unit cell is monoclinic (space group P21/c) with dimensions a = 7.845(1), b = 9.911(2), c = 19.371(2) Å, β = 94.37(1)° and contains four formula units. Hückel investigations in comparison with the electronic excitation spectrum revealed that the two bands at 2.73 and 2.62 μm-1 can be characterised as MLCT, the band at 1.62 μm-1 as d-d transition, while the band at 2.14 cm-1 has a mixed character of both MLCT and d-d transition.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976230199
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 82
    Electronic Resource
    Electronic Resource
    Darstellung und Strukturanalyse von Tetrakis-(N-Methylimidazolium)-silacyclopentandichlorid · 2 NMI (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 633-636 
    Details
    ISSN: 0044-2313
    Keywords: Tetrakis-(N-methylimidazolium)-silacyclopentane-dichloride · 2 NMI ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Crystal Structure Determination of Tetrakis-(N-Methylimidazolium)-silacyclopentanedichloride · 2 NMIThe reaction of 1,1-dichlorosilacyclopentane with N-methylimidazole in aprotic solvents leads to a 1 : 4 compound, stable at room temperature. The silicon-center of the resulting dication enlarges the coordination number from four to six. Therefore we find the chloride-ions removed from the first area of coordination. They have lost their bonding to the silicon atom. This species is the first Lewisacid/base compound consisting of a heterocyclic alkylsilicon-halide and a nitrogen-base. Two single NMI-molecules per dication are present in the unit cell with no coordination at all. That leads to an exact 1 : 6-ratio of silane to base.
    Notes: 1,1-Dichlorsilacyclopentan reagiert unter Anlagerung von vier N-Methylimidazol (NMI)-Molekülen in aprotischer Lösung zu einem sechsfach koordinierten Siliciumdikation, bie dem beiden Chloridionen aus der ersten Koordinationssphäre verdrängt werden. Hier liegt der erste Verbindungstyp eines Lewis-Säure/Lewis-Base-Adduktes bestehend aus einem heterocyclischen Alkylhalogensilan mit einer Stickstoffbase vor. Zwei weitere NMI-Moleküle befinden sich pro Dikation in der Elementarzelle, was einem exakten Verhältnis von Silan zu NMI von 1 : 6 entspricht.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.199762301100
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 83
    Electronic Resource
    Electronic Resource
    Element-Element-Bindungen. VIII. Synthese, Molekül- und Kristallstruktur des Dibrom(2,4,6-trimethylphenyl)bismutansProfessor Hans Bürger zum 60. Geburtstag gewidmet (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 941-956 
    Details
    ISSN: 0044-2313
    Keywords: Dichloro(2,4,6-trimethylphenyl)bismuthane ; dibromo(2,4,6-trimethylphenyl)bismuthane ; crystal structure ; Bi—Br‥Bi bridges ; η6-arene‥Bi contacts ; ir and Raman data ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Element-Element Bonds. VIII. Synthesis, Molecular and Crystal Structure of Dibromo(2,4,6-trimethylphenyl)bismuthaneDichloro- (1) und dibromo(2,4,6-trimethylphenyl)bismuthane (2) are obtained in relatively high yields from metathesis reactions of the corresponding bismuth(III) halides with tris(2,4,6-trimethylphenyl)bismuthane. An X-ray structure determination of the dibromo derivative 2 (monoclinic, P21/c; a = 896.2(2); b = 1531.9(3); c = 1713.3(3) pm; β = 94.31(3)° at -100±3°C; Z = 8 molecules; R = 0.059) shows two crystallographically independent molecules to build up a zigzag chain via strong Bi—Br‥Bi bridges (Bi—Br 282 and 281; Br‥Bi 302 and 302 pm) and relatively weak η6-arene‥Bi interactions (mean values Bi‥C 348 and 359 pm); for sterical reasons one bromo substituent of each molecule is not involved in coordinative bonding (Bi—Br 262 and 261 pm). To allow a better comparison of Bi—Cipso bond lengths and arene‥Bi contacts, relevant values of a greater number of related compounds have been compiled; for some of these examples arene‥Bi interactions had not been reported before. Ir and Raman bands below 350 cm-1 are assigned to stretching frequencies of the BiCl2 (1) and BiBr2 (2) fragments, respectively.
    Notes: Dichlor- (1) und Dibrom(2,4,6-trimethylphenyl)bismutan (2) erhält man in guter Ausbeute über eine Metathese des entsprechenden Bismut(III)-halogenids mit Tris(2,4,6-trimethylphenyl)bismutan. Nach den Ergebnissen einer Röntgenstrukturanalyse am Dibrom-Derivat 2 (monoklin, P21/c; a = 896,2(2); b = 1531,9(3); c = 1713,3(3) pm; β = 94,31(3)° bei -100±3°C; Z = 8 Moleküle; R = 0,059) assoziieren die beiden kristallographisch unabhängigen Moleküle über starke Bi—Br‥Bi-Brücken (Bi—Br 282 und 281; Br—Bi 302 und 302 pm) und verhältnismäßig schwache η6-Aren‥Bi-Wechselwirkungen (Mittelwerte Bi‥C 348 und 359 pm) zu Zickzack-Ketten; aus sterischen Gründen bleibt jeweils ein Brom-Substituent ohne eine weitere koordinative Bindung (Bi—Br 262 und 261 pm). Zur besseren Einordnung sind die Bi-Cipso-Abstände und die Aren‥Bi-Kontakte entsprechenden Werten aus einer größeren Zahl verwandter Verbindungen gegenübergestellt; bei einigen Beispielen wird erstmals auf bestehende Aren‥Bi-Wechselwirkungen hingewiesen. IR- und Raman-Banden unterhalb 350 cm-1 lassen sich den Valenzschwingungen des BiCl2- (1) bzw. BiBr2- Fragments (2) zuordnen.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.199762301148
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 84
    Electronic Resource
    Electronic Resource
    Darstellung, Eigenschaften und Kristallstruktur von μ-Carbidodi(pyridinphthalocyaninato(2-)eisen(IV)) und -ruthenium(IV) (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 967-972 
    Details
    ISSN: 0044-2313
    Keywords: Phthalocyaninates(2-) ; ruthenium compounds ; iron compounds ; vibrational spectra ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis, Properties, and Crystal Structure μ-Carbidodi(pyridinephthalocyaninato(2-)iron(IV)) and -ruthenium(IV))Soluble μ-carbidodi(pyridinephthalocyaninato-(2-)iron(IV)) and -ruthenium(IV) is prepared as a pyridine solvate, [{M(py)pc2-)2(μ-C)] · py (M = Fe, Ru) by the reaction of μ-carbidodi(phthalocyaninato(2-)iron(IV)) and -ruthenium(IV)) with pyridine. The isotypic complexes crystallize in the orthorhombic space group P212121 (No. 19) with lattice parameters (in Å): a = 12.692(3)713.002(3) (Fe/Ru); b = 22.186(2)722.635(6); c = 23,653(2)/23.901(6). The M atoms are virtually in the centre (Ct) of the (Np)4 plane (d(M-Ct) = 0.039(6)70.054(8) Å; Np: pyrrole-N atom). The averaged (M-Npy) distance (py: pyridine) is 1.94(1)/2.010(8) Å. The M-(μ-C)-M core is almost linear. The (M-(μ-C)) distance is 1.69(2)71.77(1) Å. The pc2- ligands are in a hitherto unknown convex staggered conformation. The asymmetric (M-(μ-C)-M) stretching vibration is observed in the IR spectrum at 9117974 cm-1, while the corresponding symmetric one is selectively enhanced only in the RR spectrum at 477 cm-1 of the iron complex.
    Notes: Lösliches μ-Carbidodi(pyridinphthalocyaninato(2-)eisen(IV) und -ruthenium(IV) wird durch die Umsetzung von μ-Carbidodi(phthalocyaninato(2-)eisen(IV) und -ruthenium(IV) mit Pyridin als Pyridin-Solvat, [{M(py)pc2-}2(μ-C)] · py (M = Fe, Ru) isoliert. Die isotypen isotypen Komplexe kristallisieren orthorombisch in der Raumgruppe P212121 (Nr. 19) mit den Gitterkonstanten (in Å): a = 12,692(3)/13,002(3) (Fe/Ru); b = 22,186(2)/22,635(6); c = 23,653(2)/23,901(6). Die M-Atom befinden sich fast im Zentrum (Ct) der (Np)4-Ebene (Np: Pyrrol-N-Atom): d(M-Ct) = 0,039(6)/0,054(8) Å. Der mittlere (M-Np)-Abstand beträgt 1,94(1)/2,010(8) Å. Die (M-(μ-C)-Abstand beträgt 1,69(2)/1,77(1) Å. Die pc2--Liganden sind in einer bislang unbekannten komplexen Staffel-Konformation einander zugeneigt. Die asymmetrische (M-(μ-C)-M)-Valenzschwingung liegt im IR-Spektrum bei 911/974 cm-1, die symmetrische beobachtet man dagegen nur im RR-Spektrum des Eisen-Komplexes bei 477 cm-1.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.199762301151
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 85
    Electronic Resource
    Electronic Resource
    Darstellung und Eigenschaften von Phthalocyaninato(2-)indaten(III) mit zweizähnigen Oxo-Liganden; Kristallstruktur von Tetra(n-butyl)ammoniumcarbonato(O,O′)-phthalocyaninato(2-)indat(III) (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 973-980 
    Details
    ISSN: 0044-2313
    Keywords: Phthalocyaninates ; indium compounds ; optical spectra ; vibrational spectra ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and Properties of Phthalocyaninato(2-)indates(III) with Bidentate Oxo Ligands; Crystal Structure of Tetra(n-butyl)ammonium Carbonato(O,O′)phthalocyaninato(2-)indate(III)Tetra(n-butyl)ammonium acidophthalocyaninato(2-)indate(III) of selected bidentate dioxo ligands (oxalate, catecholate, sulfate and carbonate) are obtained by the reaction of tetra(n-butyl)ammonium cis-dihydroxophthalocyaninato(2-)indate(III) with oxalic acid, catechol, hydrogensulfate and ammonium carbaminate. The carbonato complex crystallizes monoclinic in the space group P21/c (No. 14). InIII is hexa-coordinated by four isoindole nitrogen atoms (Niso) and two oxygen atoms of the carbonate in a cis arrangement. InIII is directed out of the centre (Ct) of the (Niso)4 plane towards the carbonate ligand (d(In-Ct)) = 0.903(1) Å. The averaged (In-Niso) and (In-O) distance is 2.1865(4) and 2.1585(5) Å, the (O-In-O′) angle 60.1(2)°. The phthalocyaninate(2-) ligand (pc2-) is in a concave distortion. The optical spectra show the typical π-π* transition of the pc2- ligand at 14600 (B region), 28000 (Q), 35000 (N) und 40500 cm-1 (L). In the IR spectra, the internal vibrations of the oxalate, sulfate and carbonate ligand and the asymmetric (In-O) stretching vibrations are well separated from the internal vibrations of the pc2- skeleton. Spectra-structure correlations are discussed.
    Notes: Tetra(n-butyl)ammoniumacidophthalocyaninato(2-)indate(III) ausgewählter zweizähniger Dioxo-Acidoliganden wie Oxalat, Katecholat, Sulfat und Carbonat werden durch die Reaktion von Tetra(n-butyl)ammoniumcis-dihydroxophthalocyaninato(2-)indat(III) mit Oxalsäure, Brenzkatechin, Hydrogensulfat und Ammoniumcarbaminat dargestellt. Der Carbonat-Komplex kristallisiert monoklin in der Raumgruppe P21/c (Nr. 14). Hexakoordiniertes InIII ist von den vier Isoindol-Stickstoffatomen (Niso) und zwei Sauerstoffatomen des Carbonats in cis-Anordnung umgeben. InIII ist aus dem Zentrum (Ct) der Ebene der vier Niso- Atome in Richtung des Carbonat-Liganden verschoben (d(In-Ct)) = 0,903(1) Å. Die mittleren (In-Niso)- und (In-O)-Abstände betragen 2,1865(4) und 2,1585(5) Å, der (O-In-O′)-Winkel 60,1(2)°. Der Phthalocyaninat(2-)-Ligand (pc2-) ist konkav verzerrt. Die optischen Spektren zeigen nur die typischen, vom Axialliganden unabhängigen π-π*-Übergänge des pc2- -Liganden bei 14600 (B-Bereich), 28000 (Q), 35000 (N) und 40500 cm-1 (L). In den IR-Spektren absorbieren die internen Schwingungen des Oxalat-, Sulfat- und Carbonat-Liganden sowie die asymmetrische (In-O)-Valenzschwingung weitgehend separiert von den pc2--Gerüstschwingungen. Die Spektren-Struktur-Korrelation wird diskutiert.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.199762301152
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 86
    Electronic Resource
    Electronic Resource
    Die Kristallstruktur von β-Al2Te3Professor Rainer Mattes zum 60. Geburtstag gewidmet (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1006-1010 
    Details
    ISSN: 0044-2313
    Keywords: Aluminium telluride ; crystal structure ; layer structures ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Crystal Structure of β-Al2Te3The crystal structure of β-Ab2Te3 has been determined by means of single crystal x-ray diffractometry. The examined crystal can be described as a pseudomerohedric twin with a plane of reflection in (001) as twin element. The refinement in P21/c (No. 14) with the crystal parameters a = 7.181(1) Å, b = 12.848(3) Å. c = 14.167(3) Å, β = 90.04(2)°, V = 1307.1 Å3 and Z = 8 resulted in a final R-value (based on F) of 0.0245. β-Al2Te3 crystallizes in a layered arrangement and represents a new structure type.
    Notes: Die Kristallstruktur von β-Al2Te3 konnte auf der Grundlage von Einkristalldaten ermittelt werden. Der vermessene Kristall lag als pseudomeroedrischer Reflektionszwilling nach (001) vor. Die Verfeinerung in P21/c (Nr. 14) mit a - 7,181(1) Å, b = 12,848(3) Å, c = 14,167(3) Å, β = 90,04(2)°, V = 1307,1 Å3 und Z = 8 konvergierte gegen einen konventionellen R-Wert von 0,0245. β-Al2Te3 kristallisiert in einer Schichtstruktur und stellt einen neuartigen Strukturtyp dar.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.199762301157
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 87
    Electronic Resource
    Electronic Resource
    Zur Struktur und Phasenbreite von Na2Gd4Cl9NO (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1011-1016 
    Details
    ISSN: 0044-2313
    Keywords: Lanthanoide ; gadolinium nitride oxide halide ; Na2Gd4Cl9NO ; crystal structure ; oxide nitride ; condensed clusters ; range of homogeneity ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Structure and Range of Homogeneity of Na2Gd4Cl9NONa2Gd4Cl9NO could be prepared as colourless compound by heating NaCl, GdN. Gd2O3 and GdCl3 in the ratio of 6 : 3 : 1 : 7 for several months at 810 K in a closed tantalum crucible (space group P21/m, a = 796,1(6) pm, b = 1112.3(5) pm, c = 916.1(7) pm, β = 106.45(6)°, Z = 2 and V = 778.0(9) · 106 pm3). The structure is built from chains of trans edge-shared [Gd4Z]-tetrahedra (Z = N or O). It is isotypic with Na2Pr4Cl9O2 and Na2Pr4Br9NO. X-ray structure determinations from two different single crystals give a hint to a range of homogeneity, Na2-xGd4Cl9N1-xO1+x, which conserves the purely salt like character of the compound via Na+ vacancies.
    Notes: Na2Gd4Cl9NO wurde durch Tempern von Nacl, GdN, Gd2O3 und GdCl3 im Verhältnis 6:3:1:7 bei 810 K im zugeschmolzenen Tantaltiegel in Form farbloser Kristalle erhalten (Raumgruppe P21/m, a = 796.1(6) pm, b = 1112.3(5) pm, c = 916.1(7) pm, β = 106.45(6)°, Z = 2, V = 778.0(9) · 106 pm3). Die Struktur ist aus Ketten trans-kantenkondensierter [Gd4Z]-Tetraeder (Z = N, O) aufgebaut Die Phase ist isotyp mit den bereits beschriebenen Verbindungen Na2Pr4Cl9O2 und Na2Pr4Br9NO. Röntgenstrukturanalysen zweier Kristalle geben Hinweise auf das Vorliegen einer Phasenbreite Na2-xGd4Cl9N1-xO1+x mit Erhalt des Charakters einer normalen Valenzverbindung.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.199762301158
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 88
    Electronic Resource
    Electronic Resource
    Komplexchemie P-reicher Phosphane und Silylphosphane. XIII [1]. [η2-{tBu2P—P=PtBu2} PtBr(PPh3)]Professor Welf Bronger zum 65. Geburtstag gewidmet (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1088-1092 
    Details
    ISSN: 0044-2313
    Keywords: [η2-{tBu2P—P=PtBu2} PtBr(PPh3)] ; crystal structure ; 1H-, 13C-, 31P-NMR spectra ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Coordination Chemistry of P-rich Phosphanes and Silylphosphanes. XIII [1]. [η2-{tBu2P—P=PtBu2} PtBr(PPh3)][η2-{tBu2P—P=PtBu2} PtBr(PPh3)] 1 is the first transition metal complex compound resulting from a phosphino-phosphinidene-phosphorane. The yellow crystals of 1 (fp. 201-203°C, decomp.) were obtained by reacting tBu2P—P=P(Br)tBu2 with either (Ph3P)2Pt · C2H4, or with Pt(PPh3)4, resp. Compound 1 crystallizes triclinic in the space group P1 (no. 2) with a = 1076.80(8) pm, b = 1344.61(8) pm, c = 1381.16(9) pm, α = 81.773(6)°, β; = 85,110(8), γ = 88,776(7).
    Notes: [η2-{tBu2P—P=PtBu2} PtBr(PPh3)] 1 ist die erste Komplexverbindung aus einem Phosphino-phosphiniden-phosphoran. Die gelben Kristalle von 1, Smp. 201-203°C (unter Zersetzung) bilden sich bei der Umsetzung von tBu2P—P=P(Br)tBu2 mit (Ph3P)2Pt · C2H4 oder Pt(PPh3)4. 1 kristallisiert triklin in P1 (Nr. 2) mit a = 1076,80(8) pm, b = 1344,61(8) pm, c = 1381,16(9) pm, α = 81,773(6)°, β; = 85,110(8)°, γ = 88,776(7).
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976230713
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 89
    Electronic Resource
    Electronic Resource
    Bi13Pt3I7: Ein Subiodid mit einer pseudosymmetrischen Schichtstruktur (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1535-1541 
    Details
    ISSN: 0044-2313
    Keywords: Bismuth platinum iodide ; subhalide ; crystal structure ; pseudo-symmetry ; stacking faults ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Bi13Pt3I7: A Subiodide with a Pseudo-Symmetric Layer StructureThe reaction of PtI2 with Bi and BiI at 630 K yields black, lustrous, air insensitive crystals of the subiodide Bi13Pt3I7. The layered crystal structure (triclinic, C1, a = 1581.0(2) pm, b = 912.6(1) pm, c = 2149.6(6) pm, α = 90.03(2)°, β = 96.96(2)°, γ = 90.11(1)°, V = 3078.6 · 106 pm3) contains edge-sharing [PtBi8/2] cubes, which form nets of Kagomé type. Iodine atoms fill the hexagonal-prismatic voids therein. These ∞2[(PtBi8/2)3I] layers are alternately separated by layers of iodine atoms or ∞1[BiI4-] zigzag-chains. The marked pseudo-symmetry of the structure favours stacking faults, which cause streaks of diffuse scattering in the diffraction pattern.
    Notes: Aus der Reaktion von PtI2 mit Bi und BiI bei 630 K erhält man schwarze, metallisch glänzende und luftbeständige Kristalle des Subiodids Bi13Pt3I7. In der schichtartig aufgebauten Kristallstruktur (triklin, C1, a = 1581,0(2) pm, b = 912,6(1) pm, c = 2149,6(6) pm, α = 90,03(2)°, β = 96,96(2)°, γ = 90,11(1)°, V = 3078,6 · 106 pm3) liegen Kagomé-Netze aus kantenverknüpften [PtBi8/2]-Würfeln vor, deren hexagonal-prismatische Lücken mit Iodatomen gefüllt sind. Diese ∞2[(PtBi8/2)3I]-Schichten sind abwechselnd durch eine Lage von Iodatomen oder eine Schicht aus parallel angeordneten ∞1[BiI4-]-Zickzackketten getrennt. Die in der Struktur stark ausgeprägte Pseudosymmetrie begünstigt Stapelfehler, welche sich auch in diffusen Streifen im Beugungsbild äußern.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976231011
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 90
    Electronic Resource
    Electronic Resource
    Reaktionen von Lanthanoidhalogeniden mit Alkalibenzylverbindungen. Darstellung und Kristallstrukturen von [(tmeda)(C6H5CH2)2Y(μ-Br)2Li(tmeda)], [(tmeda)2SmBr(μ-Br)2Li(tmeda)] und [(dme)2SmBr(μ-Br)]2 (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1542-1546 
    Details
    ISSN: 0044-2313
    Keywords: Yttrium(III) ; samarium(II) ; benzyl complexes ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Lanthanide Halides with Alkalibenzyl Compounds. Synthesis and Crystal Structures of [(tmeda)(C6H5CH2)2Y(μ-Br)2Li(tmeda)], [(tmeda)2SmBr(μ-Br)2Li(tmeda)] and [(dme)2SmBr(μ-Br)]2Alkali-benzyl compounds react via a metathesis reaction with lanthanide halides to benzyl complexes of the rare earths. Reaction of [(C6H5CH2)Li(tmeda)] with YBr3 leads to the complex [(tmeda)Y(C6H5CH2)2 (μ-Br)2Li(tmeda)] 1, in which Yttrium and lithium are linked via two bromide bridges. However, the reaction of [(C6H5CH2)Li(tmeda)] with SmBr3 in toluene/tmeda leads under reduction of the Sm ion to the compound [(tmeda)2SmBr(μ-Br)2Li(tmeda)] 2. 2 reacts with DME to yield the dimeric compound [(dme)2SmBr(μ-Br)]2 3. The structures of 1-3 were determined by X-ray single crystal structure analysis:1:Space group P21/c, Z = 4, a = 829.5(6) pm, b = 1477.9(11) pm, c = 2575.0(10) pm, β = 92.03(6)°,2:Space group P21, Z = 2, a = 954,7(3) pm, b = 1338.5(6) pm, c = 1244.9(5) pm, β = 107.51(3)°,3:Space group P1, Z = 1, a = 797.2(7) pm, b = 818.3(7) pm, c = 1169.7(8) pm, α = 100.96(6)°, β = 92.03(6)°, γ = 91.75(7)°.
    Notes: Alkalibenzylverbindungen reagieren mit Lanthanoidhalogeniden unter Salzabspaltung zu Benzylkomplexen der Seltenen Erden. [(C6H5CH2)Li(tmeda)] bildet mit YBr3 den Komplex [(tmeda)(C6H5CH2)2Y(μ-Br)2Li(tmeda)] 1, in dem das Yttriumion mit Lithium über zwei Bromo-Brücken verknüpft ist. Bei der Reaktion von [(C6H5CH2)Li(tmeda)] mit SmBr3 in Toluol/TMEDA erfolgt hingegen unter Reduktion die Bildung von [(tmeda)2SmBr(μ-Br)2Li(tmeda)] 2. Diese Verbindung bildet mit DME den zweikernigen Komplex [(dme)2SmBr(μ-Br)]2 3. Die Strukturen von 1, 2 und 3 wurden durch Einkristallstrukturanalyse geklärt:1:Raumgruppe P21/c, Z = 4, a = 829,5(6) pm, b = 1477,9(11) pm, c = 2575,0(10) pm, β = 92,03(6)°,2:Raumgruppe P21, Z = 2, a = 954,7(3) pm, b = 1338,5(6) pm, c = 1244,9(5) pm, β = 107,51(3)°,3:Raumgruppe P1, Z = 1, a = 797,2(7) pm, b = 818,3(7) pm, c = 1169,7(8) pm, α = 100,96(6)°, β = 92,03(6)°, γ = 91,75(7)°.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976231012
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 91
    Electronic Resource
    Electronic Resource
    Two New Modifications of [P(C6H5)4]2[Cu2I4] (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1555-1560 
    Details
    ISSN: 0044-2313
    Keywords: Iodocuprate(I) ; [Cu2I4]2- ; tetraphenylphosphonium ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zwei neue Modifikationen von [P(C6H5)4]2[Cu2I4]Bei der Reaktion von granuliertem Kupfer mit Iod und [P(C6H5)4]I in trockenem Aceton unter Stickstoffatmosphäre wurden Einkristalle von zwei neuen Modifikationen von [P(C6H5)4]2[Cu2I4] erhalten. Sie kristallisieren monoklin, Raumgruppe P21/n (Nr. 14), a = 11.550(6), b = 7.236 (2), c = 27.232 (13) Å, β = 98.13(3)°, V = 2253(2) Å3 und Z = 2 ([P(C6H5)4]2[Cu2I4]-C) bzw. Raumgruppe Cc (Nr. 9), a = 17.133(5), b = 15.941(5), c = 18.762(6) Å, β = 114.02(1)°, V = 4681(3) Å3 und Z = 4 ([P(C6H5)4]2[Cu2I4] -D). In diesen Verbindungen liegen dimere di-μ-iodo-diiodocuprat(I)-Einheiten vor, die planar (C) bzw. gewinkelt (D) sind.
    Notes: Single crystals of two new modifications of [P(C6H5)4]2[Cu2I4] were obtained by reaction of granulated copper with iodine and [P(C6H5)4]I in dry acetone under nitrogen atmosphere. They crystallise monoclinically, space group P21/n (No. 14), a = 11.550(6), b = 7.236(2), c = 27.232(13) Å, β = 98.13(3)°, V = 2253(2) Å3, and Z = 2 ([P(C6H5)4]2[Cu2I4]-C), and space group Cc (No. 9), a = 17.133(5), b = 15.941(5), c = 18.762 (6) Å, β = 114.02(1)°, V = 4681(3) Å3, and Z = 4 ([P(C6H5)4]2[Cu2I4]-D), respectively. In these compounds the [CuI2]- anions form dimers di-μ-iodo-diiodocuprate(I), which are either planar (C) or folded (D).
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976231014
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 92
    Electronic Resource
    Electronic Resource
    Synthese und Eigenschaften von Eisen(II)-Komplexen mit vier- und fünfzähnigen N,S-Chelatliganden. Kristallstruktur von [Fe(GBMA)py] · py (GBMA2- = Glyoxal-bis-(2-mercaptoanil)) (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1644-1650 
    Details
    ISSN: 0044-2313
    Keywords: Iron(II) complexes ; Schiff's base ligands ; crystal structure ; magnetic properties ; Mössbauer spectra ; electrochemistry ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Properties of Iron(II) Complexes with tetra- and pentadentate N,S-Chelate Ligands. Crystal Structure of [Fe(GBMA)py] · py (GBMA2- = Glyoxal bis-(2-mercaptoanil))The complexes glyoxal-bis-(2-mercaptoanil)iron(II) [Fe(GBMA)], diacetyl-bis-(2-mercaptoanil)iron(II), [Fe(DBMA)] and o-phthalaldehyde-bis-(2-mercaptoanil)iron(II) [Fe(PhBMA)] have been synthesized by reaction of the corresponding protonated ligands with anhydrous iron(II)-acetate. Pyridine-2,6-dialdehyde-bis-(2-mercaptoanil)iron(II), [Fe(PyBMA)] was obtained by a template synthesis with pyridine-2,6-dialdehyde, 2-aminothiophenol and iron(II)-acetate. Recrystallizing the complexes [Fe(GBMA)] and [Fe(DBMA)] from pyridine afforded [Fe(GBMA)py] · py and [Fe(DBMA)py] · py. For all complexes the magnetic properties have been determined, and the Mössbauer spectra were recorded at 82 K. Compounds [Fe(GBMA)] and [Fe(DBMA)] show quasi reversible redox properties in the cyclovoltammogram, while for [Fe(PhBMA)] an irreversible oxidation was observed. [Fe(GBMA)py] · py crystallizes in the monoclinic space group P21 with a = 1288.7(1), b = 1242.63(5), c = 1396.0(1) pm, β = 98.24(1)°, and Z = 4. In the neutral complex the Fe atom has a square pyramidal coordination with the pyridine nitrogen atom in apical position. The basal plane is formed by two nitrogen and two sulfur atoms of the ligand GBMA2-. The iron is located 40 pm above the pyramidal base. Its average distances to the donor atoms of the GBMA ligand are Fe—N = 190 pm, and Fe—S = 222 pm, while the distance to the nitrogen atom of the coordinated pyridine molecule is 207 pm.
    Notes: Die Komplexe Glyoxal-bis-(2-mercaptoanil)eisen(II), [Fe(GBMA)], Diacetyl-bis-(2-mercaptoanil)eisen(II), [Fe(DBMA)] und o-Phthaldialdehyd-bis-(2-mercaptoanil)eisen(II), [Fe(PhBMA)] wurden durch direkte Umsetzung der entsprechenden protonierten Liganden mit wasserfreiem Eisen(II)-acetat dargestellt. Die Synthese von Pyridin-2,6-dialdehyd-bis-(2-mercaptoanil)eisen(II), [Fe(PyBMA)] erfolgte mit Hilfe einer Templatsynthese aus 2,6-Pyridindialdehyd, 2-Aminothiophenol und Eisen(II)-acetat. Durch Umkristallisieren in Pyridin wurden aus [Fe(GBMA)] und [Fe(DBMA)] die Verbindungen [Fe(GBMA)py] · py und [Fe(DBMA)py] · py erhalten. Von allen Komplexen wurden die magnetischen Eigenschaften bestimmt und die Mössbauer-Spektren bei 82 K registriert. [Fe(GBMA)] und [Fe(DBMA)] zeigen im Cyclovoltammogramm quasireversibles Redoxverhalten, während bei [Fe(PhBMA)] eine irreversible Oxidation beobachtet wird. [Fe(GBMA)py] · py kristallisiert monoklin in der Raumgruppe P21 mit a = 1288,7(1), b = 1242,63(5), c = 1396,0(1) pm, β = 98,24(1)° und Z = 4. Im Neutralkomplex ist das Fe-Atom quadratisch-pyramidal mit dem Pyridin-Stickstoffatom in apikaler Position koordiniert. Die Pyramidenbasis wird von den zwei Stickstoff- und Schwefelatomen des Liganden GBMA2- aufgespannt. Das Fe-Atom befindet sich 40 pm oberhalb der Pyramidenbasis. Die Abstände zu den Donoratomen des GBMA-Liganden betragen im Mittel Fe—N = 190 pm und Fe—S = 222 pm. Der Fe—N-Abstand zum Pyridinstickstoffatom liegt bei 207 pm.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976231027
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 93
    Electronic Resource
    Electronic Resource
    Zur Kenntnis von cis-NatriumhyponitritProfessor Rudolf Hoppe zum 75. Geburtstag gewidmet (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1803-1809 
    Details
    ISSN: 0044-2313
    Keywords: Hyponitrites ; cis-Na2N2O2 ; preparation ; properties ; crystal structure ; vibrational spectra ; 15N-MAS-NMR spectra ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: To the Knowledge of cis-Sodium HyponitriteSurprisingly, cis-sodium hyponitrite can be prepared by reacting gaseous N2O and solid Na2O. For the first time, the structure of a simple salt of cis hyponitrous acid has been determinated unambigously. According to an abinitio structure determination based on powder data, cis-Na2N2O2 crystallizes monoclinic (P21/c, a = 5.107(1); b = 9.211(1); c = 6.159(1) Å; β = 97.91(1)°; Z = 4). Results of spectroscopic investigations (vibrational spectroscopy, 15N-MAS-NMR) agree with the symmetry of the cis-N2O22- anion as it has been proved by the crystal structure. Consider able differences regarding some chemical and physical properties have been observed for samples of cis-Na2N2O2 synthesized via different routes.
    Notes: Durch Gas-Festkörper-Reaktion von N2O und Na2O läßt sich überraschend cis-Natriumhyponitrit darstellen. Auf der Basis der so erhaltenen reinen, gut kristallisierten Präparate gelang erstmals die eindeutige strukturelle Charakterisierung eines einfachen Salzes der cis-Hyposalpetrigen Säure. Gemäß der voraussetzungsfrei anhand von Pulverdaten durchgeführten Strukturbestimmung kristallisiert cis-Na2N2O2 monoklin (P21/c, a = 5,107(1); b = 9,211(1); c = 6,159(1) Å; β = 97,91(1)°; Z = 4). Die Resultate der spektroskopischen Untersuchungen (Schwingungsspektroskopie, 15N-MAS-NMR) stehen im Einklang mit der durch die Kristallstrukturanalyse ermittelten Symmetrie des cis-N2O22--Anions. Präparate von cis-Na2N2O2, die auf verschiedenen Synthesewegen dargestellt wurden, zeigen auffallende Unterschiede in einigen chemischen und physikalischen Eigenschaften.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976231124
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 94
    Electronic Resource
    Electronic Resource
    Lewis-Säure-Base-Reaktionen von Goldtrihalogeniden mit Bismuttrihalogeniden - Synthese und Kristallstrukturen von AuBiX6 (X = Cl, Br)Professor Rudolf Hoppe zum 75. Geburtstag gewidmet (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1810-1814 
    Details
    ISSN: 0044-2313
    Keywords: Gold trichloride ; gold tribromide ; bismuth trichloride ; bismuth tribromide ; solvothermal synthesis ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Lewis-Acid-Base-Reactions of Gold Trihalides with Bismuth Trihalides - Synthesis and Structures of AuBiX6 (X = CI, Br)Gold trihalides AuX3 (X = Cl, Br) react with bismuth trihalides in sealed glass ampoules to the 1 : 1 adducts AuBiX6 (X = Cl, Br). AuBiCl6 is obtained by a chemical transport reaction at 220°C, whereas AuBiBr6 was synthesized by solvothermal reaction in SiBr4 at 150°C. Both compounds crystallize triclinic, space group P1, Z = 4. AuBiCl6; a = 698.3(4) pm; b = 1009.3(5) pm; c = 1381(1) pm; α = 104.98(5)°; β = 94.73(5)°; γ = 110.06(3)°; V = 867(1) · 106 pm3. AuBiBr6: a = 735.7(4) pm; b = 1055.7(5) pm; c = 1445(1) pm; α =104.88(5)°; β = 94.25(5)°; γ = 110.18(4)°; V =1001(1) ·106pm3. The structures are build formally of square-planar [AuX4]- and chains of edge-connected ([BiX4/2]+)n units. Since each Bi ion is surrounded by eight halogenide ions in a square-antiprismatic form, the structure can alternatively be described as consisting of chains of edge sharing ([BiX4X4/2]3-)n antiprisms connected by Au3+ ions.
    Notes: Goldtrihalogenide AuX3 (X = CI, Br) reagieren mit den entsprechenden Bismuttrihalogeniden BiX3 (X = Cl, Br) in geschlossenen Ampullen zu den 1 : 1-Addukten AuBiX6. AuBiCl6 entsteht bei 220°C unter den Bedingungen des chemischen Transportes, während AuBiBr6 wegen der geringen thermischen Stabilität von AuBr3 unter solvothermalen Bedingungen in SiBr4 als Lösungsmittel bei 150°C dargestellt wurde. Beide Verbindungen sind isotyp und kristallisieren triklin in der Raumgruppe P1, Z = 4, mit den Gitterkonstanten a = 698,3(4) pm; b = 1009,3(5) pm; c = 1381(1) pm; α = 104,98(5)°; β = 94,73(5)°; γ = 110,06(3)° für AuBiCl6 und a = 735,7(4) pm; b = 1055,7(5) pm; c = 1445(1) pm; α = 104,88(5)°; β = 94,25(5)°; γ = 110,18(4)° für AuBiBr6. Die Strukturen sind aus quadratisch-planaren [AuX4]--Ionen und Ketten aus kantenverknüpften ([BiX4/2]+)n-Einheiten aufgebaut. Da die Bi-Ionen von acht Halogenid-Ionen in Form eines quadratischen Antiprismas umgeben sind, kann die Struktur alternativ so beschrieben werden, daß sie aus Ketten kantenverknüpfter ([BiX4X4/2]3- )n-Antiprismen besteht, die über Au3+ -Ionen verbunden sind.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976231125
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 95
    Electronic Resource
    Electronic Resource
    Tetraphenylphosphonium-tetradecachlorotetraarsenat(III), (PPh4)2As4Cl14 (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1033-1034 
    Details
    ISSN: 0044-2313
    Keywords: Tetraphenylphosphonium-tetradecachlorotetraarsenate(III) ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tetraphenylphosphonium Tetradecachlorotetraarsenate(III), (PPh4)2As4Cl14The title compound was obtained by reaction of As4S4, PPh4Cl and chlorine in dichloromethane. According to its X-ray crystal structure analysis, the As4Cl142- ion can be described as an association product of two AsCl4- units and two AsCl3 molecules. The As atoms and ten Cl atoms are approximately in a plane, the remaining four Cl atoms alternately take positions above and below this plane. The As atoms have distorted ψ octahedral coordination.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976230702
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 96
    Electronic Resource
    Electronic Resource
    Metallkomplexe mit biologisch wichtigen Liganden. XCV. η5- Pentamethylcyclopentadienyl-Rhodium-, -Iridium-, (η6-Benzol)-Ruthenium- und Phosphan-Palladium-Komplexe von Prolinmethylester und ProlinamidProfessor Anton Meller zum 65. Geburtstag gewidmet (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1903-1911 
    Details
    ISSN: 0044-2313
    Keywords: Rhodium ; ruthenium ; iridium ; palladium ; proline ; amide complexes ; proline methylester complexes ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metal Complexes of Biologically Important Ligands. XCV. η5-Pentamethylcyclopentadienyl Rhodium, Iridium, η6- Benzene Ruthenium, and Phosphine Palladium Complexes of Proline Methylester and Proline AmideProline methylester (L1) and proline amide (L2) give with the chloro bridged complexes [(η5 -C5Me5)MCl2]2 (M = Rh, Ir), [(η6 -benzene)RuCl2]2 and [Et3PPdCl2]2 N and N,O coordinated compounds: (η5 -C5Me5)M(Cl2)L1 (1, 2 M = Rh, Ir), [(η5-C5Me5) Rh(Cl)(L2)]+Cl- (5), [(η6- C6Me6) Ru(Cl)(L2)]+Cl- (6), [(η6-p-cymene)Ru(Cl)(L2)]+Cl- (7), [(eta;5-C5Me5)M(Cl)(L2-H+)] (9, 10 M = Rh, Ir), (Et3P)Pd(Cl)2L1 (3), and [(Et3P)Pd(Cl)(L2)]+Cl- (8). The NMR spectra indicate that for 5 and 6 only one diastereoisomer is formed. The complexes 1, 2, 3 and 5 were characterized by X-ray diffraction.
    Notes: Prolinmethylester (L1) und Prolinamid (L2) bilden mit den chlorverbrückten Komplexen [(η5-C5Me5)MCl2]2 (M = Rh, Ir), [(η6-p-Cymol)RuCl2]2 und [Et3PPdCl2]2 Verbindungen mit N- und N,O-Koordination: (η5-C5Me5)M(Cl2)L1 (1, 2 M = Rh, Ir), [(η5-C5Me5) Rh(Cl) (L2)]+Cl- (5), [(η6- C6Me6)Ru(Cl) (L2)]+Cl- (6), [(η6-p- Cymol)Ru(Cl)(L2)]+Cl- (7), [(η5- C5Me5)M(Cl)(L2-H+)] (9, 10 M = Rh, Ir), (Et3P)Pd(Cl)2L1 (3) und [(Et3P)Pd(Cl)(L2)]+Cl- (8). Die NMR Spektren weisen darauf hin, daß von 5 und 6 jeweils nur ein Diastereoisomeres entsteht. Die Komplexe 1, 2, 3 und 5 wurden durch Röntgenstrukturanalyse charakterisiert.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976231214
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 97
    Electronic Resource
    Electronic Resource
    Über kristalline Natriumhydroxogallate (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1483-1488 
    Details
    ISSN: 0044-2313
    Keywords: Nonasodium bis(hexahydroxogallate) trihydroxide hexahydrate ; decasodium bis(hexahydroxogallate) tetrahydroxide ; disodium tetrahydroxogallate chloride ; crystal structure ; 71Ga MAS NMR ; 23Na MAS NMR ; DTA, DTG, guinier lenné technique ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: About Crystalline Sodium HydroxogallatesTwo crystalline sodium hydroxogallates 4,5 Na2O · Ga2O3 · 13,5 H2O (I) and 5 Na2O · Ga2O3 · 8 H2O (II), as well as a crystalline phase of the composition Na2O · Ga2O3 · 4 H2O · 2 NaCl (III) are described.
    Notes: Es werden zwei kristalline Natriumhydroxogallate 4,5 Na2O · Ga2O3 · 13,5 H2O (I) und 5 Na2O · Ga2O3 · 8 H2O (II) sowie eine kristalline Phase der Zusammensetzung Na2O · Ga2O3 · 4 H2O · 2 NaCl (III) beschrieben.(I) kristallisiert aus Natriumgallatlösungen eines breiten Konzentrationsfeldes und hat nach Einkristallröntgenstrukturanalyse [1] eine dreidimensional vernetzte Struktur aus monomeren [Ga(OH)6]3--Anionen, die über NaO6-Koordinationspolyeder untereinander verbunden sind; daneben sind Kristallwasser und weitere Hydroxidionen enthalten.Damit ist (I) als Nonanatrium-bis(hexahydroxogallat)-trihydroxid-hexahydrat (Na9[Ga(OH)6]2(OH)3 · 6 H2O) zu formulieren; Isotypie besteht zu dem entsprechenden Natriumhydroxoaluminat [2, 3]. 5 Na2O · Ga2O3 · 8 H2O II) läßt sich aus (I) in Gegenwart von Natriumhydroxid durch Entwässern über P4O10 bei Raumtemperatur unter Schutzgas (N2) erhalten. Es kristallisiert tetragonal, ist isotyp mit Na10[Al(OH)6]2(OH)4 [4] und dementsprechend als Na10[Ga(OH)6]2(OH)4 zu formulieren. Durch Zusatz von Natriumchlorid zu Natriumgallatlösungen läßt sich Na2O · Ga2O3 · 4 H2O · 2 NaCl (III) isolieren, das ebenfalls tetragonal und isotyp zu Na2[Al(OH)4]Cl [5] ist. Es handelt sich demnach um das Dinatriumtetrahydroxogallatchlorid Na2[Ga(OH)4]Cl. Die Ergebnisse der 71Ga- und 23Na-MASNMR-Messungen an den Verbindungen (I) bis (III) und deren thermisches Verhalten werden diskutiert.(I) crystallizes from sodium gallate solutions in a wide concentration field; from the X-ray single crystal diffraction analysis [1] results a three dimensional network structure, consisting of monomeric [Ga(OH)6]3- anions connected by NaO6 octahedra groups. Furthermore the structure contains water of crystallization and further hydroxide ions. (I) has to be formulated as nonasodium bis(hexahydroxogallate) trihydroxide hexahydrate Na9[Ga(OH)6]2(OH)3 · 6 H2O; it is isotypic with the corresponding sodium hydroxoaluminate [2, 3]. 5 Na2O · Ga2O3 · 8 H2O (II) was obtained from (I) in presence of sodium hydroxide by dehydration over P4O10 in an inert atmosphere (N2) at room temperature. (II) crystallizes tetragonally and is isotypic with Na10[Al(OH)6]2(OH)4 [4]. Accordingly it could be described as a decasodium bis(hexahydroxogallate) tetrahydroxide, Na10[Ga(OH)6]2(OH)4. Na2O · Ga2O3 · 4 H2O · 2 NaCl (III) was obtained by addition of sodium chloride to sodium gallate solutions, (III) crystallizes also tetragonally and is isotypic with (Na2[Al(OH)4]Cl [5]. Correspondingly, it has to be formulated as disodium tetrahydroxogallate chloride Na2[Ga(OH)4]Cl. The results of 71Ga and 23Na MAS NMR investigations of the compounds (I) to (III) and their thermal behaviour are discussed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976230925
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 98
    Electronic Resource
    Electronic Resource
    Synthese und Kristallstruktur von Cs3Y7Se12 (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1501-1502 
    Details
    ISSN: 0044-2313
    Keywords: Cesium yttrium selenide ; Cs3Y7Se12 ; rare-earth compounds ; preparation ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Crystal Structure of Cs3Y7Se12The oxidation of yttrium metal with selenium in the presence of CsCl (7 d, 700°C, evacuated silicia tubes) results in the formation of pale yellow, lath-shaped single crystals of Cs3Y7Se12. The crystal structure (orthorhombic, Pnnm, Z = 2, a = 1272.8(3), b = 2627.7(5), c = 413.32(8) pm) consists of edge- and vertex-connected [YSe6] octahedra forming a rocksalt-related network [Y7Se12]3-. One-dimensional infinite channels along [001], apt to take up extra cations, provide coordination numbers of 6 and 7 + 1, respectively, for two crystallographically different Cs+.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976231005
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 99
    Electronic Resource
    Electronic Resource
    Die isotypen Verbindungen BaRh2Si2, BaIr2Si2 und BaPt2Ga2 - eine monokline Verzerrungsvariante der CaRh2B2-StrukturProfessor Welf Bronger zum 65. Geburtstag gewidmet (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1561-1566 
    Details
    ISSN: 0044-2313
    Keywords: Barium ; platinum ; silicide ; gallium ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Isotypic Compounds BaRh2Si2, BaIr2Si2, and BaPt2Ga2 - a Monoclinic Distortion Variant of the CaRh2B2 StructureThe new compounds BaRh2Si2 (monoclinic, P21/c, a = 792.6(1) pm, b = 664.5(7) pm, c = 767.9(4) pm, β = 91.2(1)°, Z = 4, 2867 reflexions, 47 parameters, R = 0.024), BaIr2Si2 (monoclinic, P21/c, a = 792.47(6) pm, b = 664.28(6) pm, c = 772.22(6) pm, β = 92.181(7)°, Z = 4, 1939 reflexions, 47 parameters, R = 0.037) and BaPt2Ga2 (monoclinic, P21/c, a = 850.4(1) pm, b = 647.3(1) pm, c = 819.8(1) pm, β = 95.97(1)°, Z = 4, 1506 reflexions, 47 parameters, R = 0.038) were prepared by reaction of the elements. Their structures were determined from single crystal data. The compounds crystallize isotypically with a distortion variant of the CaRh2B2 type of structure.
    Notes: Die neuen Verbindungen BaRh2Si2 (monoklin, P21/c, a = 792,6(1) pm, b = 664,5(7) pm, c = 767,9(4) pm, β = 91,2(1)°, Z = 4, 2867 Reflexe, 47 Parameter, R = 0,024), BaIr2Si2 (monoklin, P21/c, a = 792,47(6) pm, b = 664,28(6) pm, c = 772,22(6)pm, β = 92,181(7)°, Z = 4, 1939 Reflexe, 47 Parameter, R = 0,037) und BaPt2Ga2 (monoklin, P21/c, a = 850,4(1) pm, b = 647,3(1) pm, c = 819,8(1) pm, β = 95,97(1)°, Z = 4, 1506 Reflexe, 47 Parameter, R = 0,038) wurden durch Reaktion der Elemente dargestellt und ihre Strukturen mit Einkristalldaten bestimmt. Die Verbindungen kristallisieren isotyp in einer Verzerrungsvariante des CaRh2B2-Typs.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976231015
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 100
    Electronic Resource
    Electronic Resource
    Bi4RuBr2 und Bi4RuI2: Zwei Varianten einer Kolumnarstruktur mit flächenverknüpften quadratischen [RuBi8/2]-Antiprismen (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1583-1590 
    Details
    ISSN: 0044-2313
    Keywords: Bismuth ruthenium bromide ; bismuth ruthenium iodide ; subhalide ; crystal structure ; chemical bonding ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Bi4RuBr2 and Bi4RuI2: Two Varieties of a Column Structure with Face-Sharing [RuBi8/2] Square AntiprismsReaction of the elements yields black, lustrous, air insensitive crystals of the subhalides Bi4RuI2 (tetragonal, I4/m, a = 1183.9(2) pm, c = 669.7(2) pm, V = 938.66 · 106 pm3) and Bi4RuBr2 (monoclinic, I112/m, a = 1211.9(2) pm, b = 1072.6(2) pm, c = 663.9(2) pm, γ = 91.63(1)°, V = 862.64 · 106 pm3). The structures of the homöotypic compounds contain ∞1[RuBi8/2] strands of face-sharing square antiprisms. Halogen atoms lie above the edges of alternate Bi4 squares. Thereby chemical bonding differs significantly within the two types of Bi4 squares. Though the Ru atoms on the central axis of the strand of antiprisms form pairs, extended Hückel calculations give no evidence of Ru—Ru bonds.
    Notes: Durch Umsetzung der Elemente werden schwarze, metallisch glänzende, luftstabile Kristalle der Subhalogenide Bi4RuI2 (tetragonal, I4/m, a = 1183,9(2) pm, c = 669,7(2) pm, V = 938,66 · 106 pm3) und Bi4RuBr2 (monoklin, I112/m,a = 1211,9(2) pm, b = 1072,6(2) pm, c = 663,9(2) pm, γ = 91,63(1)°, V = 862,64 · 106 pm3) erhalten. In den Strukturen der homöotypen Verbindungen liegen ∞1[RuBi8/2]-Stränge aus flächenverknüpften, quadratischen Antiprismen vor. Die Kanten jedes zweiten Bi4-Quadrates in einer Säule sind mit Halogenatomen überbrückt. Dadurch unterscheiden sich die Bindungsverhältnisse in den beiden Sorten von Bi4-Quadraten wesentlich. Die Ru-Atome auf der zentralen Achse des Antiprismenstranges bilden Paare, doch liegen nach Extended-Hückel-Rechnungen keine Ru—Ru-Bindungen vor.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976231018
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...