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
  • Inorganic Chemistry  (83,665)
  • 1
    Electronic Resource
    Electronic Resource
    Asymmetric Catalysis, 105Part 104: Ref.. Stereoselective Hydrogenation of Folic Acid with Immobilized Optically Active Rhodium(I)/Diphosphane Catalysts (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 55-62 
    Details
    ISSN: 0009-2940
    Keywords: Diastereoselective hydrogenation ; Folic acid ; Immobilized optically active rhodium(I)/diphosphane catalysts ; Leucovorin ; HPLC analysis of 5-formyltetrahydrofolic acid derivatives ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: For the hydrogenation of the C=N bonds in the pyrazine ring of the vitamin folic acid (1) optically active rhodium(I)/diphosphane complexes immobilized on supports such as silica gel or Al2O3 were used. The reduction was carried out at 50 bar hydrogen pressure in an aqueous solution buffered to pH 7. Thus, 5,6,7,8-tetrahydrofolic acid (2) was obtained which contains a new asymmetric center at C-6 of the pterine system. Therefore, in combination with the (S) configuration of the natural L-glutamic acid part of the molecule two diastereomers with (6S,S) and (6R,S) configuration arise. The relatively unstable tetrahydrofolic acid (2) was converted into its 5-formyl derivative folinic acid (4) by treatment with methyl formate/formic acid in a 5:1 mixture of DMSO/pyridine. The Ca salt of folinic acid (4) is the widely used drug leucovorin. The diastereomers were separated by silica gel HPLC. To the column bovine serum albumine (BSA) is covalently bound. With optically active rhodium(I)/diphosphane catalysts, immobilized on silica gel supports, a diastereoselectivity of up to 90% could be achieved in the hydrogenation of folic acid (1).
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300109
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Conformational Mobility and Preferences of Allyl-Type Organometallic Intermediates: Dodec-2-enylpotassium (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 83-88 
    Details
    ISSN: 0009-2940
    Keywords: Torsional (Z/E) isomerization ; Selectivity, regio- and stereo- ; Allylsilanes ; Allylic oxidation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Alk-2-enylpotassium compounds having the endo conformation are synthetically very valuable precursors of (Z)-olefinic derivatives substituted at the outward allylic position. They may be generated by „stereoconservative‘ metalation of the readily available (Z)-alk-2-enes by using the superbasic mixture of butyllithium and potassium tert-butoxide or by metalation under similar conditions of stereorandom mixtures of alk-2-enes or alk-1-enes followed by torsional isomerization of the concomitantly formed exo conformers to the thermodynamically more stable endo species. The principal factors that dictate the rate and the extent of the endo/exo equilibration are the substrate geometry, the solvent, the temperature, the reagent stoichiometry, and catalysis.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300113
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Organophosphorus Compounds, 114. Tetracyclic Phosphorus-Aluminium-Carbon Compounds - Synthesis by Cooligomerization of Kinetically Stabilized Phosphaalkynes with Trialkylaluminium CompoundsDedicated to Professor Michael Hanack on the occasion of his 65th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 255-259 
    Details
    ISSN: 0009-2940
    Keywords: Phosphaalkynes ; Triorganoaluminium compounds ; Cooligomerization ; Cage compounds ; Aluminium compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: When the trialkylaluminium reagents 5 are allowed to react with phosphaalkynes 4 in n-pentane, a highly selective phosphaalkyne cyclotrimerization with incorporation of two organometallic units occurs (→ 6). The tetracyclooctane derivatives 6a-e represent the first examples of phosphorus-aluminium-carbon cage compounds. The polycyclic products 6 are able to function as ligands in transition-metal complexes (→ 7), which is illustrated by the reactions of 6b, c with nonacarbonyldiiron and pentacarbonyl(tetrahydrofuran)tungsten, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300219
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    On the Ligating Properties of Sulfonate and Perchlorate Anions Towards Zinc (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 283-289 
    Details
    ISSN: 0009-2940
    Keywords: Zinc ; Sulfonate ligands ; Perchlorates ; Coordination modes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Attempts are reported to incorporate sulfonate and perchlorate anions as ligands in zinc complexes of tripodal ligands. Using tris(benzimidazolylmethyl)amine (BIMA) only the aqua complexes [ (BIMA)Zn-OH2](RSO3)(ClO4) and [(BIMA)Zn-OH2](RSO3)2(R=CH3, CF3, p-tolyl) were accessible. Using substituted pyrazolylborates (Tp*), the same three sulfonate anions were found to be ligands in the complexes Tp*Zn-OSO2R. Spectroscopic evidence for perchlorate coordination in Tp*ZnClO4 · 2 DMSO conflicts with crystallograpic evidence against it in Tp*ZnClO4 · pyridine. The crystal structures of [(BIMA)Zn-OH2](CH3SO3)2, TpCum,MeZn-OS02CH3, TPtBu,MeZn-OSO2C6H4-p-CH3, and [TpCum,MeZn · NC5H5]ClO4 were determined.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300223
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Multiple Bonds Between Main-Group Elements and Transition Metals, CLXIV. Alkylrhenium(VI) Oxides-Synthesis and Characterization (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 295-298 
    Details
    ISSN: 0009-2940
    Keywords: Rhenium ; Oxides ; Alkyl ligands ; Dirhenium compounds ; Metal-metal interactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Most alkylrhenium(VII) oxides, e.g. ((cyclo)-C3H5)Re03 (2) are rather sensitive to temperature and moisture with the prominent exception of methyltrioxorhenium (1). The corresponding alkylrhenium(VI) oxides of formula [RR′(O)- Re(μ-O)]2 [R=R′=(cyclo)-C3H5 (3), iPr (4); R=CH3, R′=C2H5 (5), R=CH3, R′=iPr (6)] are much more stable in this regard. They can be handled in air at room temperature. They were synthesized from Re207 and dialkylzinc precursors, fully characterized and are available in much higher yields than their ReVII congeners. Mixed tetraalkyltetraoxodirhenium(VI) complexes (R # R′) synthesized from 1 and dialkylzinc compounds form as a mixture of cis/trans isomers. They are oily liquids at room temperature. The Re=O and Re-Re stretching force constants as a measure of the bond strengths, were determined from IR and Raman data.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300225
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Heterobimetallic Complexes with a Propynylidene C3-Bridge: General Synthetic Routes to Bimetallic Ethynylcarbene Complexes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 479-488 
    Details
    ISSN: 0009-2940
    Keywords: Heterobimetallic complexes ; Carbene complexes ; Alkynes ; Coupling reaction ; Bridging ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Sequential reaction of the dimethylamino(trimethylsilylethylnyl)carbene complexes [(CO)5M'=C(NMe2)C≡CSiMe3] [M' = W (1a)] with KF/THFMeOH, nBuLi and transition metal halides, [XMLn], affords heterobimetallic propynyliden complexes of the type [(CO)5M'=C(N-Me2)C≡CMLn] [MLn = Ni(PPh3) Cp (4a, b). Ni(PMe2Ph)2- {Mes) (Mes=2,4,6-C6H2Me3) (5a), Rh(CO)(PPh3)2 (6a), Fe(CO)2Cp (7a,b)]. In contrast, reaction of 1a with MeLi · LiBr and [IFe(CO)2Cp] yields the novel N-metallated complex [(CO)5W=C{N(ME)Fe(CO)2Cp}C≡CSiMe3] (8a). The complexes [(CO)5M'=C(NMe2)C≡CMLn=Fe(CO)2Cp (7a, b), Ru(CO)2Cp (10a,b), Ru(CO)(PPh3)Cp (11a), Mn(CO)5 (12a), Re(CO)5 (13a)] are accessible by Pd-catalyzed coupling of the C-stannylated carbene complexes [(CO)5M'=C-(NMe2)C≡CSnBu3] (9a, b) with [XMLn]. The related monomethylaminocarbene complexes [(CO)5M'=C(NHMe)C≡ CSnBu3] (16a, b), obtained by stannylation of [(C))5M'=C(NHMe)C=CH] (15a, B) with Bu3SnNEt2, react with [IFe(CO)2Cp] to give the bimetallic complexes [(CO)5M'=C(NHMe)C≡CFe(CO)2Cp] (17a, b). The complexes 4a, 5a, 7a and 10a were characterized by X-ray structural analysis. The spectroscopic and structural data suggest that the two metal centers in 4-7, 10-13, and 17 interact only weakly.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300407
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Diazosulfonate Substitutents: A Route to Transition-Metal Complexes with Switchable Water Solubility (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 515-520 
    Details
    ISSN: 0009-2940
    Keywords: Water-soluble ligands ; Diazo compounds ; Photolysis ; Cleavage reactions ; Zinc ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The single-crystal X-ray structure analysis of the diazosulfonate p-H2N-C6H4-N=N-SO3Na 3 features a Z configuration of the diazo moiety and a nitrogen-sulfur bond. Each sodium atom is coordinated by one diazosulfonate substitutent in a chelating manner. Upon reaction of 3 with excess salicylaldehyde, the highly water-soluble Schiff base ligand 6 is obtained in good yield. Treatment of ZnCl2 with 2 equiv. of 6 gives the zinc complex 7. In all cases, the solubilizing diazosulfonate groups can be cleaved off photolytically, which offers an opportunity to precipitate the molecules from their aqueous solutions.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300411
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Organoamido- and Aryloxolanthanoids, 15Part 14: Ref. [1a].. Organometallic Compounds of the Lanthanoids, 116Part 115: Ref. [1b].. Syntheses of Low Coordination Number Divalent Lanthanoid Organoamide Complexes, and the X-ray Crystal Structures of Bis[(N-2,6-diisopropylphenyl)(N-trimethylsilyl)amido]bi(tetrahydrofuran)samarium(II)and -ytterbium(II) (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 409-415 
    Details
    ISSN: 0009-2940
    Keywords: Mercury ; Lanthanides ; Lanthanoid(II) complexes ; (N-2,6-Diisopropylphenyl)(N-trimethylsily)amide complexes ; Bis(trimethylsilyl)amide complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Mercury(II) amide complex Hg[N(SiMe3)(2,6-iPr2C6H3)]2 (1) was prepared by reaction of HgBr2 with Li[N(SiMe3) 2,6-iPr2C6H3)] in diethyl ether solvent. Redox transmetallation reactions of 1 with elemental samarium, europium or ytterbium in THF solvent (THF = tetrahydrofuran), generated the novel divalent complexes Ln[N(SiMe3)(2,6-iPr2C6H3]2(THF)2 with Ln = Sm (2), Eu (3) and Yb (4). 4 was also synthesized by reaction of elemental ytterbium, HgPh2 and HN(SiMe3)(2,6-Me3)2]2(THF)2 [Ln = Sm (5), Yb (6)] by reaction of the metals with HgPh2 and HN(SiMe3)2. Thermal desolvation of 4 under high vacuum gave Yb(N)(SiMe3)2,6-iPr2C6H3)]2 (THF) (7), whereas under identical conditions 6 yielded the solvent-free complex [Yb[N{SiMe3)2]2]2. (8). The new compounds 1-4 and 7 are hydrocarbon soluble and 171Yb-NMR spectra were recorded for 4, 6, 7 and 8. X-ray crystal structure determinations of 2 and 4 revealed four-coordinate, distorted tetrahedral metal environments augmented by weak Ln…ipso-C(aryl) interactions.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300316
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Recent Developments in the Chemistry of Covalent Azides (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 443-452 
    Details
    ISSN: 0009-2940
    Keywords: Ab initio calculations ; Azides ; Density functional calculations ; Covalent azides ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The experimental and theoretical chemistry of covalently bound azides is an area that has seen considerable renaissance over the past 10 years. This review is not exhaustive in scope but rather focuses on and highlights certain aspects in this field. In particular, the stability and dissociation of HN3 is discussed at a very high level of theory (CASSCF and MCSCF-CI) and compared and contrasted with experimental data and results from „medium“-level ab initio computations (MP2, B-LYP). From these results credence is given to those values calculated for larger systems and heavy elements for which very high level computations are not possible. The experimentally well-characterized covalent halogen azides (XN3, where X = F, Cl, Br, I) as well as the heavy-element group-15 compound Sb(N3)3 are discussed. The review also includes discussion of the bond properties of the highly unstable N-bound azides ON-N3 and (FSO2)2N-N3. In the final chapter attention is drawn to the recently predicted and eventually experimentally verified elusive species OCN-NCO, which is isoelectronic to the hitherto unknown diazide N6.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300403
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Divalent Tin and Lead Compounds EX2 Acting as Bridging Ligands in [{(CO)5M}2EX2]2- (E = Sn, Pb; M = Cr, Mo, W): Preparation and PropertiesDedicated to Professor G. E. Herberich on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 687-699 
    Details
    ISSN: 0009-2940
    Keywords: Tin ; Lead ; 119Sn NMR ; Salt metathesis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of Na2[M2(CO) 10] (M = Cr, Mo, W) with SnHal2 (Hal = Cl, Br) is a well established procedure for the synthesis of anions of type A, [{(CO)5M)SnHal3]-. Conditions are described which, for the same type of procedure, result in the additional formation of dianions of type B, [{(CO)5M}2SnHal2]2-. Procedures for separating these two types of anions in the form of their stable [Ph4P]+ or [nBu4N]+ salts by appropriate salt metathesis are presented. The structures of theses species have been characterized by X-ray analysis of three salts containing type A anions and two salts containing type B anions. The reactivity of the type B salts containing the bulky cations [Ph4P]+ or [nBu4N]+, respectively, is remarkably low; the salts are, however, transformed into highly reactive sodium salts by further metathesis with Na[BPh4]. In such salts the halide substitutents are easily exchanged as shown by the synthesis of ]})CO(5Cr}2oxinato]- (4)- from [Na-(THF)x]2[{(CO)5Cr}2SnCl2] and sodium 8-oxoquinolate, Na[C9H6NO]. The structure of the anion, 4 is compared to the structure of [[(CO)5Cr)SnCl2· THF] and sodium 8-oxochinolate. The preparation of the dinuclear anions [{(CO)5Cr}2E(OOCCH3)2]2- (E = Sn, 2g; E = Pb, 3) is accomplished by the reaction of [Ph4P]2[Cr2(CO)10] with the corresponding acetates E(OOCCH3)2. While 2g and 3 are formal analogues of the type-B anions, their structures reveal an asymmetrical η2-coordination of the two acetato ligands, in each case ending up in a 4+2 coordination for the main group centres, instead of the four-coordination observed for [{(CO)5M}2SnHal2]2-, All compounds have been characterized by usual spetroscopic and analytical techniques. X-ray analyses have been performed for selected examples. 119Sn-NMR data are presented for all of the compounds which contain tin-centred ligands.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300604
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 11
    Electronic Resource
    Electronic Resource
    Organophosphorus Compounds, 118Part 2: 117: Ref1. Reactions of 1-Chloro-1H-phosphirenes with Nucleophiles (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 711-723 
    Details
    ISSN: 0009-2940
    Keywords: Phosphorus heterocycles ; 1H-Phosphirenes ; Nucleophilic substitution reactions at 1H-phosphirenes ; Metal-complexation of functionalized 1H-phosphirenes ; Carbonyl complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The halogen atoms in the 1-chloro-1H-phosphirenes, 5a-c, are easily substituted on reaction with organolithium and Grignard reagents, 14a-p, with formation of the corresponding O-, N-, C-, Si-, and Ge-substituted 1H-phosphirenes, 15a-t. C1/H exchange reactions also occur on reaction with lithium metal hydrides (5a → 17). Furthermore, substitution reactions are also realized with the alkali metal borates, 18a-g (→19a-g); the same is true for reactions with trimethylsilyl cyanide and azide (→22a-d). Some of the substitution products have been characterized in the form of their metal complexes, 16, 23, 24, and 25.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300607
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    Synthesis of Germatranyl Derivatives of Esters of Carboxylic Acids via Organometallic (Si, Ge, Sn) Reagents (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 739-746 
    Details
    ISSN: 0009-2940
    Keywords: Germatranes ; Organotrihalogenogermanes ; Organometallic (Si, Ge, Sn) reagents ; Transmetallation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Trialkylstannyl esters of tris(2-hydroxyalkyl)amines, N(CH2CHROSnAlk3)3 (9-11 (R = H, Me; Alk = Et, Bu), react with X3GeC(R1)(R2)COOR3 (12-17) (X = Cl or Br; R1, R2=H, Me, Ph, SiMe3, COOEt; R3=Me, Et) to give esters of α-germatranylcarboxylic acids, N(CH2CHRO)3GeC(R1)(R2)-COOR3 (1-8), in high yields. The synthesis of esters 12-17 is reported. Esters of α-germatranyldiphenylacetic acid 24 and 25 can be obtained by treatment of diphenylketene with Et3SnOMe to give in situ Et3SnC(Ph2)COOMe (23), followed by reaction with GeCl4 to give in situ Cl3GeC(Ph2)COOMe (22 and further reactions with 9 or 11, respectively. Reduction of germatrane 6 with LiAlH4 in diethyl ether leads to cleavage of the germanium-carbon bond with subsequent formation of (2-hydroxyethyl)trimethylsilane. The crystal structures of 3, 6 and 7 are reported. 1-Acyloxygermatranes 26 and 27 are obtained by treatment of 1-methoxygermatrane (28) with diphenyl- and dichloroacetic acid, respectively.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300611
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    Base-Induced Synthesis of a Tetrastannatriazabicyclo[3.1.1]heptane from Tris)dimethylchlorostannyl)amineDedicated to Professor W. Sieber on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 765-769 
    Details
    ISSN: 0009-2940
    Keywords: Tin - Nitrogen cage compounds ; Sn—X—Sn intramolecular bridges ; Distannylamine pyridine adduct ; Tin ; Moessbauer spectroscopy ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tris(dimethylchlorostannyl)amine (2a) reacts with pyridine in a 3:4 molar ratio to produce the tin-nitrogen containing bicyclo[3.1.1]heptane (3) with elimination of the adduct Me2SnCl2·2 py. Treatment of the distannylamine 2,6-[Pr2H3N(SnMe2Cl)2 (4) with pyridine, however, leads to the formation of the 1:1 pyridine adduct 4 and this can be regarded as a model to explain the route to 3. The molecular structures of 3 and 5 were determined by multinuclear magnetic resonance spectroscopy in solution, as well as by X-ray structure analysis of their crystals. Typical structural features for both compounds are intramolecular Sn—X—Sn bridges. Support for the structures comes from MS fragmentation patterns, IR spectra, and the Mössbauer spectra.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300615
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    Thermal Reactions of 5-Alkylidene-4,5-dihydro-3H-1,2,4(λ3)-diazaphospholes (4-Phosphapyrazolines) - A Route to Various P—Heterocycles and to 2-PhosphabutadienesDedicated to Professor M. Hanack on the occasion of his 65th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 779-788 
    Details
    ISSN: 0009-2940
    Keywords: 1,2,4-Diazaphospholes ; Phosphiranes, alkylidene- ; 2-Phosphabutadienes ; Phosphorus heterocycles ; pyrazolines, thermolysis ; Rearrangements ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 5-alkylidene-4,5-dihydro-3H-1,2,4(λ3)-diazaphospholes (4-phosphapyrazolines) are thermally much more stable than related compounds without the exocyclic double bond. Thermolysis reactions typically occur in the range 110-150°C in toluene solution, and different, mostly competing, reaction pathways are observed. Thermal extrusion of nitrogen from 8a-g gives rise to β-phosphanaylsiloxyalkenes 10, benzo[c]-phosphole derivatives 11, 14 and 115, (β-siloxyalkylidene)-Phosphiranes 12, and dihydro-1,3-oxaphospholes 13. The thermolysis of 5-alkylidene-4,5-dihydro-4-trimethylsilyl-3-trimethylsilyloxy-3H-1,2,4-dizaphospholes 17 afforded three products, including the highly substituted and stable 2-phosphabutadienes 18 formed by nitrogen extrusion and rearrangement. Finally, the 4-chloro-3-trimethylsilyloxy-substituted heterocycle 21 was transformed at 170°C into 4H-1,2,4-diazaphosphole 23. The structures of 13c and 18a were determined by single-crystal X-ray diffraction.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300617
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    N-Alkylation of Ammine - Undecahydro-Closo-dodecaborate(1-)Dedicate to Prof. Dr. Walter Siebert on the occasion of hbis 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 795-799 
    Details
    ISSN: 0009-2940
    Keywords: Boron ; Alkylations ; N ligands ; Dodecaborate ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reactions of the ammine-undecahydro-closo-dodecaborate(1-) anion with alkyl halides have been studied in detail. The degree of alkylation of the nitrogen was found to be dependent upon the steric demands of the alkyl groups. The derivatives were characterized by NMR and infrared spectroscopy. Four compounds were crystallized for single crystal X-ray diffraction studies. The tetrahedral coordination of the nitrogen atom of the bis-alkylated derivatives was found to deviate towards planarity with increasing steric hindrance of the substitutents. - The syntheses, crystal structures, and spectral properties of four N-alkyl derivatives of [H3N—B12H11]-, ammine - undecahydro-closo-dodecaborate(1-) (3), are reported. Alkylation of 3 with ethyl iodide was achieved in dimethyl sulfoxide using potassium hydroxide as base. This led to orthorhombic crystals of [N(nC4H94][(CH3CH2)3N—B12H11] (4). The reaction of 3 with benzyl chloride resulted in the bisbenzylated product, isolated as triclinic crystals of [PPN][(C6H5CH2)2 NH—B12H11] (5). The alkylation of 3 with 2-bromopropane gave a mixture of the mono- and bisalkylated products. The monoalkylated derivative [PPN][(CH3)2CH)NH2-12H11] (6, crystallized in the triclinic space group p1) and the bisalkylated product [PPN]{[(CH3)2NH—B12H11) (7, monoclinic, P21./c) were separated on the basis of their different water solubilities. The solid-state structures of the compounds 4-7 revealed a slight distortion of the B12 icosahedron. The length of the B(1)-N(1) bond was found to be dependent on the steric requirements of the attached amine, e.g. primary amine 〈 secondary amine 〈 tertiary amine. This is demonstrated by the variation in the B—N bond length; from 157.8(2) pm for 6, 158.5(5) pjm for 5, 160.0(3) pm for 7, to 163.7(6) pm for 4.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300619
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    Unusual Ring-Closure Reactions During the Oxidation of 1,1′-Bi(3-methylphosphol-2-ene) with Hexafluoroacetone  -  Formation of a Tricyclic Fluorine-Containing PhosphoraneDedicated to Professor Rudolf Taube on the occasion of hbis 65th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 819-822 
    Details
    ISSN: 0009-2940
    Keywords: Hexafluoroacetone ; Phosphorus, pentacoordinated ; Diphosphane diselenide ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reduction of the isoprene - PCl3 adduct 1 with magnesium powder, or with Si2Cl6, furnished P-chloro-3-methyl-phosphol-2-ene, 2, in satisfactory yield. Further reduction of 2 with Si2Cl6 gave the new trichlorosilyl-3-methylphosphol-2-ene, 3. The reaction of 2 with magnesium powder, with 3, or with 1/2 equivalent of Si2Cl6 provided the new γ3P-γP-diphosphane 1,1′-bi(3-methylphosphol-2-ene) 4. Reduction of 4 with Si2Cl6 led to 3. Oxidation of 4 with selenium gave the 1,2-diphosphane diselenide, 5. The oxidation of 4 with hexafluoroacetone led to a mixture of products, from which a novel tricyclic phosphorane 6 was separated. the structure of 196 was determined by X-ray diffraction; the coordination geometry at phosphorus in distorted trigonal bipyramidal, with a very long equatorial P - C(CF3)2 bond of 193.2(2) pm.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300623
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    Organophosphorus Compounds, 119Part 118: Ref.. The Phosphaalkyne Cyclotetramer System  -  Syntheses, Valence Isomerizations, and Reactions (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 823-834 
    Details
    ISSN: 0009-2940
    Keywords: Phosphaalkynes ; Phosphaalkyne cyclotetramers ; Cage compounds ; Valence isomerization ; Cyclotetramerization ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In contrast to their all-carbon analogues, phosphaalkyne cyclooligomers only became accessible a few years ago. A milestone in the chemistry of cyclotetramers was the synthesis and structural characterization of the tetraphosphacubane 5, obtained as a thermolysis product of tert-butylphosphaacetylene (1). Since then, the construction of eleven cyclotetramers has been achieved, covering seven different frameworks (A-G). As a consequence of the use of kinetically stabilized phosphaalkynes as starting materials, all known cyclotetramers bear sterically demanding substituents (tert-butyl, tert-pentyl, 1-adamantyl). Cyclotetramerizations are not only achieved by thermolysis of 1, but also by alternative and selective routes such as transition-metal-mediated, Lewis acid- and base-induced processes, as well as by cycloadditions to phosphaalkyne cyclotrimers. Interestingly, these tetramers can be interconverted by various valence isomerizations. The results of thermal and photochemically-induced rearrangements are in good agreement with MO calculations carried out for the parent compounds. Phosphaalkyne cyclotetramers exhibit a highly interesting reactivity and other peculiar features. One outstanding example is the tetraphosphacubane 5, which shows unusual structural and spectroscopic properties as a result of its unique bonding arrangement.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300703
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    2-Phosphanylphosphinines as Bridging Ligands for Dinuclear Transition Metal Carbonyls (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 843-849 
    Details
    ISSN: 0009-2940
    Keywords: P ligands ; Phosphorus heterocycles ; 2-Phosphanylphosphinines ; Dinuclear complexes ; Metal carbonyls ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 2-phosphanyl-4,5-dimethylphosphinines 1-5 are powerful bridging ligands able to stabilize metal-metal single and triple bonds between low-valent transition metal centres. Their reaction with Mn2(CO)10 in refluxing xylene yields the corresponding Mn2(CO)8 complexes 6 and 7. Reaction with [Fe2Cp2(CO)4] under UV irradiation similarly yields the Fe-Fe-bridged Fe2Cp2(CO)2 complexes 8 and 9. An additional observation is that the 2-phosphininyl-3,4-dimethylphosphaferrocene 10 is formed upon reaction of the 2-phospholylphosphinine 5 with [Fe2Cp2(CO)4] at high temperature under CO pressure. A clean addition occurs at the Mo≡Mo triple bond of [Mo2Cp2(CO)4] to give the Mo-Mo single-bonded complexes 11-15. The thermolysis of these complexes succeeds when the phosphanyl group is a phosphonite P(OEt)2 (13) or P(OAr)2 (14), affording cleanly the Mo2Cp2(CO)4 triple-bonded complexes 16 and 17, respectively. The metal-metal triple bonds of these complexes readily add two molecules of CO to reform 13 and 14, or one molecule of tBu-N≡C to give 18 and 19. The X-ray crystal structure analysis of the MO2C2(CO)4 complex 13a, with the 2-P(OEt)2- phosphinine, shows a gauche orientation of the two Cp rings and very short P-Mo bonds of 2.3565(4) and 2.406(2) Å to the phosphinine and P(OEt)2 groups, respectively.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300706
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    On the Polymorphism of White PhosphorusDedicated to Professor Gottfried Huttner on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1235-1240 
    Details
    ISSN: 0009-2940
    Keywords: Phosphorus ; Phase transitions ; Molecular crystal ; Crystal growth ; Low-temperature crystal structure ; Librational motion ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: White phosphorus occurs in three modifications. The α form, which exists at roomtemperature, transforms reversibly to the β form at -77°C. The α · β transformation may be strongly delayed. Quenching the α form to -185°C followed by slow warming results in an exothermic reactions with formation of the γ form which transforms into the β form at -120°C in an endothermic reaction. A transition β · γ is not observed. The γ form is characterized by its powder diagram. The structure of the β form is redetermined from a single crystal at -185°C (P., α = 547.88(5), b = 1078.62(11), c = 1096.16(11)pm, α= 94.285(8), β = 99.695(7), γ = 100.680(7)., V = 623.79(10) · 106 pm3, Z = 6 formula units per cell). The P4 molecules exhibit pronounced librational motion in spite of the low temperature of investigation. The arrangement of the centers of the tetrahedra corresponds to the atom positions in the γ-plutonium structure, which is discussed in relation to the bcc structure.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300911
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    Chiral Polysiloxane-Fixed Metal 1,3-Diketonates (Chirasil-Metals) as Catalytic Lewis Acids for a Hetero Diels-Alder Reaction -Inversion of Enantioselectivity Upon Catalyst -Polymer Binding (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 879-885 
    Details
    ISSN: 0009-2940
    Keywords: Asymmetric catalysis ; Cycloadditions ; Lewis acids ; Polymers ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A dimethylpolysiloxane chain is covalently bound to the monomeric Lewis acid catalyst (1R)-(+)-oxovanadium(1V) bis[3- heptafluorobutanoylcamphorate] [(+)-5a] at the C-10 position of the camphor moiety yielding the novel chiral polymeric (1S)-( +)-oxovanadium(1V) bis[3-heptafluorobutanoylcamphorate] -dimethylpolysiloxane [( +)-6a][1]. The Lewis acid promoted hetero Diels-Alder reaction of trans-l-methoxy-3-(trimethylsilyloxy)- 1,3-butadiene (1) and benzaldehyde (2) is studied in the presence of the enantiomerically pure monomeric (5a, 5b) and polymeric (6a, 6b) catalysts. The monomeric and polymeric catalysts of identical chirality[1] invoke opposite enantioselectivities toward the formation of 2-phenyl- 2,3-dihydro-4H-pyrone (4). This remarkable result is corroborated by numerous control experiments. Thus, it is demonstrated that the environment of the active site of the catalyst is changed when the complex is fixed to a polymeric chain. In contrast to 5 and 6, the monomeric 12 and polymeric 13 europium(III) tris[3-heptafluorobutanoylcamphorates] of identical chirality invoke the same enantioselectivity toward the formation of 4. The concept of polymer attachment is utilized to recover the catalyst from the reaction mixture by precipitation and to recycle it for subsequent catalytic runs.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300711
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 21
    Electronic Resource
    Electronic Resource
    Cp3Zr(acetonitrile)+: Structure of an Electron-Rich Organometallic d0-Cation (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 899-902 
    Details
    ISSN: 0009-2940
    Keywords: Cp3Zr complexes ; Cationic organometallic Lewis acid ; d0-Configured metal complex ; Acetonitrile ; crystal structure analysis of Zirconium ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The organometallic salt [Cp3Zr(N≡C-CH3)]+ [CH3B-(C6F5)3]- (3a) has been prepared by treatment of Cp3ZrCH3 with B(C6F5)3 followed by the addition of acetonitrile. X-ray crystal structure analysis of 3a shows that its cation consists of three uniformly coordinated η5-cyclopentadienyl ligands about the zirconium atom. The acetonitrile ligand is end-on coordinated. In the linear [Zr] -N≡C-CH3 unit the C≡N triple bond [N-C2 1.126(5) Å] is slightly shorter than in the free acetonitrile molecule [dC≡N = 1.141(2) Å], the structure of which was determined as a reference by X-ray diffraction of a crystal obtained by IR-laser-induced zone melting on the diffractometer.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300714
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 22
    Electronic Resource
    Electronic Resource
    Benzophenoneimine Complexes of Copper(1)Dedicated to Professor J. Strähle on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 947-950 
    Details
    ISSN: 0009-2940
    Keywords: Copper ; N ligands ; Copper(I) complexes ; (Imine)copper(I) complexes ; Ketimines ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reactions of [(MeCN)4Cu]BF4 with two or three equivalents of benzophenoneimine lead to the formation of [(Ph2C=NH)2]BF4 (1) and [ (Ph2C=NH)3Cu]BF4 (2), respectively. A further equivalent of the ligand does not coordinate to the cation of complex 2. The crystal structures of both compounds were determined. 1 shows a linearly two-coordinated copper(I) center with a Cu-N distance of 1.877(2) Å. In compound 2 a distorted trigonal planar coordination of copper is observed with N-Cu-N angles of 114.5(2), 112.9(2) and 132.4(2)°, corresponding to two nearly equal Cu-N distances [Cu-N2 1.947(5) and Cu-N3 1.934(5) Å] dnd a significantly longer third one (Cu-N1 2.011(5) Å]. A comparison of these data with recently determined structures of bis(benzophenoneimine)silver(I) and -gold(I) complexes shows that the covalent radii of the monovalent coinage metals decrease in the order Ag(I) 〉 Au(I) 〉 Cu(I).
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300721
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 23
    Electronic Resource
    Electronic Resource
    Organoantimony Oxides: Preparation and Crystal Structures of [(2-PhOC6H4)O (C6H4)2Sb]2O2 and (o-Tol2Sb)4O6Dedicated to Prof. Dr. Gottfried Huttner on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 959-961 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Air oxidation of (Oxydi-2,1-phenylene)(2-phenoxyphenyl)stibane (1) gives the phenoxystibane oxide [(2-PhOC6H4)O(C6H4)2Sb]2O2 (2). Single crystals of (o-Tol2Sb)4- O4(O2)2 (3) were obtained by air oxidation of o-TolSb-(SiMe3)2. Crystal structures of 2 and 3 are reported.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300724
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 24
    Electronic Resource
    Electronic Resource
    Zinc Pyrazolylborate Complexes with Phenoxide and Alkoxide LigandsDedicated to Professor Wolfgang Beck on the occasion of his 65th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 975-980 
    Details
    ISSN: 0009-2940
    Keywords: Zinc complexes ; Phenoxide complexes ; Alkoxide complexes ; Terminal alkoxide ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The zinc hydroxide complexes Tp*Zn-OH of highly substituted pyrazolylborate ligands react with phenols, and alcohols, of sufficient acidity, in a condensation reaction with release of H2O. Starting with phenols the following were attached:phenolate, p-nitropehnolate, o-vanillinate, o-hydroxymethylphenolate, o,o-bis(hydroxymethyl) -p-methylphenolate. Whilst aliphatic alcohols and benzyl alcohol did not react, their derivatives, with highly electronegative substituents could be incorporated. Thus, the arylmethoxides OCH2C6F5 and OCH2C6H4NO2-p, as well as the alkoxides OCH2CF3 and OCH2CCl3, were attached. 2-Mercaptoethanol was bound via its thiolate function. The crystal structures of TpCum,Me ZN-OC6H4NO2-p,TpCum,Me ZN-OCH2-C6F5, TpCum,Me ZN-OCH2CF3, TpCum,Me ZN-OCH2CCl3 and TpCum,MeZn-SCH2CH2OH were determined.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300727
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 25
    Electronic Resource
    Electronic Resource
    Pseudoelement Compounds, XPart IX: Ref. Synthesis and Crystal Structure of New Complexes of the Type trans-[Pt(H)X(PPh3)2 with Cyanamide and Cyanomethanide LigandsDedicated to Professor S. Engels on the occasion of his 65th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1007-1012 
    Details
    ISSN: 0009-2940
    Keywords: Platinum ; Nitrocyanamide ; Nitrosodicyanomethanide ; 1,1,3, 3-Tetracyano-2-azapropenide ; 1,1,2,3,3-Pentacyanopropenide ; Hydrido complexes ; Coordination modes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The new coordination compounds trans-[Pt(H)X(PPh3)2] with NCN- and C(CN)2-functionalized anions (X- = [N(O)C(CN)2]-, [NO2NCN]-, [N{C(CN)2}2]-, [NCC{C-(CN)2}2]-, have been characterized by 1H-, 31P-, 13C-NMR, and IR spectroscopy and elemental analyses the crystal structures of trans-[Pt(H)N(O)C(CN)2(PPh3)2], trans- [Pt(H)N{C(CN)2}2(PPh3)2], and trans-[Pt(H)NCC{C(CN)2}2-(PPh3)2) have been determined by X-ray diffraction. Remarkably, [N(O)C(CN)2]- is coordinated through the central nitrogen atom, while [N{C(CN)2}2]- and [NCC(C(CN)2]2]- are bonded through terminal nitrogen atoms of a C(CN)2 unit.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300730
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 26
    Electronic Resource
    Electronic Resource
    New Coupling Reactions and Phosphorylations Using Organozinc Reagents (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1021-1027 
    Details
    ISSN: 0009-2940
    Keywords: Zinc ; Chirality ; Cross-coupling ; Phosphorylations ; Catalysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This Microreview on the chemistry of organozinc reagents starts by briefly showing the methods of preparation of organozinc compounds and then discusses the considerable synthetic utility of zinc organometallics for the formation of new carbon-carbon bonds in the presence of transition-metal catalysts. Finally, the use of organozinc chemistry for the preparation of polyfunctional and chiral phosphanes is described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300802
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 27
    Electronic Resource
    Electronic Resource
    Synthesis and Structures of Bis(tetramethylipiperidino)aluminum Halides-X-ray Crystal Structures of tmp2AlX (X = Cl, Br, I) and [tmp2A1(μ-F)l2 (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1047-1052 
    Details
    ISSN: 0009-2940
    Keywords: Bis(tetramethylipiperidino)aluminum halides ; Alkoxy((tetramethylpiperidino)aluminum halides ; 27Al-NMR spectra ; Aluminum ; Amides ; Synthetic methods ; Bridging ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: N-Lithio-2,2,6,6-tetramethylpiperidine [Li(tmp)] reacts with AlX3 (X = Cl, Br) in diethyl ether/ n-hexane solution to generate the products of substitution and ether cleavage, [tmpAl(X)(μ-OEt)], (la, X = Cl; 1b, X = Br). However, when the reaction is allowed to proceed in n-hexane alone, an almost quantitative yield of compounds tmp2AlX (2a, X = Cl; 2b, X = Br; 2c, X = I) is obtained. According to 27AI-NMR spectroscopy, mass spectroscopy, cryoscopy, and X-ray crystal structure determinations, these compounds are monomeric in the solid state, in solution, and in the gas phase. 2b reacts with AgBF4 yielding the fluoride-bridged dimer (tmp2AlF), 2d, as shown by X-ray crystal structure determination.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300805
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 28
    Electronic Resource
    Electronic Resource
    Structure and Reactivity of Sodium Phenoxide - Following the Course of the Kolbe-Schmitt Reaction (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1461-1465 
    Details
    ISSN: 0009-2940
    Keywords: Kolbe-Schmitt reaction ; Solid-state structures ; Sodium phenoxide ; Solvent Complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Solvent-free sodium phenoxide (NaOPh) crystallises as a polymer and forms a polymeric chain in the [0 0 1] direction. The low coordination of the sodium atoms, as evident in the crystal structure, is confirmed by the easy coordination of oxoligands (α-donors). Hence, the four-membered ring chain of the solvent-free sodium phenoxide is separated by oxoligands, and forms partial structures as the polymer fragments. Thus, NaOPh crystallises in THF with the formation of an Na6O6 core, consisting of two face-fused heterocubes, and in N, N, N′, N′-tetramethyl urea (TMU) with the formation of a Na4O4 heterocubane. The solvent-free NaOPh-CO2 complex obtained from the addition of CO2 to a solution of sodium phenoxide is, when exposed to a temperature of 80°C, subject to an irreversible phase transition, as demonstrated by FT-IR and DTA studies. The complex formed at 80°C is, apparently, another intermediate of the Kolbe-Schmitt reaction.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301017
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 29
    Electronic Resource
    Electronic Resource
    1,8-Bis(phosphanyl)naphthalenes: 1,8-Bis[(diethylamino)phosphanyl]-naphthalene, 1,8-Bis(dichlorophosphany)naphthalene, and 1, 3-Dichloro-2,-3-dihydro-1,3-dioxo-2-oxa-1,3-diphosphaphenaleneDedicated to Professor Huns Burger on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1485-1489 
    Details
    ISSN: 0009-2940
    Keywords: Naphthalenes ; Phosphanes ; Phosphorus heterocycles ; Protecting groups ; Strained molecules ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1.8-dilithionaphthalene 1 reacted with bis(dimethylamino)-chlorophosphane to form 1,8-bis[(diethylamino)phosphanyl]-naphthalene 2, whose structure was confirmed by X-ray crystal structure analysis; there are two independent molecules, in which the P(NEt2)2 groups adopt an eclipsed conformation. Reaction of 2 with gaseous HCl gave in low yield 1,8-bis-(dichlorophosphanyl)naphthalene 3, which was characterized by 1H- and 31P-NMR spectroscopy, mass spectrometry and elemental analysis. Attempted recrystallization of 3 led to oxidative hydrolysis which furnished 4, an anhydride of a bis(chlorophosphonic acid), whose structure was elucidated by X-ray crystal structure analysis. The geometry of 4 reveals a relief of strain from the bis (aminophosphane) 2; the naphthalene groups are less distorted and the P atoms are displaced less far from the naphthalene best plane.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301021
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 30
    Electronic Resource
    Electronic Resource
    Coordination Compounds of Coinage Metals with Vinylidenebis(diphenyl-phosphane) and Its Disulfide and Their Reactivity towards NucleophilesDedicated to Professor P. Royo on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1513-1517 
    Details
    ISSN: 0009-2940
    Keywords: Gold ; Silver ; Diphosphane ; Diphosphane Disulfide ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Vinylidenebis(diphenylphosphane) reacts with gold(I) or gold(III) compounds to give dinuclear {[{Au(C6F5)]2[(PPh2)2C=CH2{] or [Au{PPh2C(=CH2)Ph2P)]2(ClO4)2] or mononuclear complexes ([Au(C6F5)3(PPh2C(=CH2)Ph2P)]}, respectively. The latter reacts with gold(I) or silver(I) compounds to afford dinuclear [[Au(C6F5)3[PPh2C(=CH2)Ph2P}AuX], X=Cl or C6F5) or trinuclear species {[{Au(C6F5)3{PPh2C(=CH2)Ph2P{]2M]ClO4, M=Au or Ag}. No addition of nucleophiles to the C=C double bond is observed in these complexes, which contain the diphosphane acting as bridging or monodentate ligand. (SPPh2)2C=CH2 reacts with AgClO4 to give [Ag{SPPh2C(=CH2)Ph2PS}]2-(ClO4)2or[Ag[PPh2C(=CH2)Ph2P]2]ClO4. The crystal structure of [Au(C6F5)3{PPh2C(=CH2)Ph2P}Au(C6F5)] has been established by X-ray crystallography, and confirms the expected square planar and linear geometry for the Au111 and Au1 centres, respectively.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301026
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 31
    Electronic Resource
    Electronic Resource
    Diastereoselective Synthesis and Molecular Structure of a Bicyclic and a Cage Phosphane (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1547-1550 
    Details
    ISSN: 0009-2940
    Keywords: Phosphane ; 1,3α., 5,7β-Tetrakis(trifluoromethyl)-6,-9-dioxa-2-phosphabicyclo[3.3.1]nonane-3β, 7α-diol ; 1,7-Trifluoromethyl-3,5-methyl1-2,4.8-trioxa-6-phosphaadamantane ; Phosphorus heterocycles ; Ketones ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A two-step formal insertion of 1,1,1,5,5,5-hexafluoro- (2a) and 1,111-trifluoropentane-2,4-dione (2b) into the P-H bonds of phosphane gave the primary a-hydroxyphosphanes 3 and 4, precursors for the resulting secondary phosphanes, 6,9-dioxa-2-phosphabicyclo[3.3.l]nonane (6a) and 2,4,8-trioxa-6-phosphaadamantane (7), both formed diastereospecifically. The molecular structures of 6a and 7 were established by single-crystal X-ray structure analysis which revealed two independent molecules for 6a in the unit cell possessing a chair-boat conformation with a C-P-C angle of 95.4(2)°, and a characteristic heteroadamantane geometry for 7, with the corresponding angle being smaller by 4.9°.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301031
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 32
    Electronic Resource
    Electronic Resource
    Reactions of Complex Ligands, LXXVII. Axial-Chiral Metal Carbenes: Synthesis and Structure of 1,1-Binaphthyl-Derived Carbonyl-Carbene Complexes of Chromium (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1605-1609 
    Details
    ISSN: 0009-2940
    Keywords: Axial-chiral complexes ; Biaryls ; Carbene complexes ; Circular dichroism ; Chromium complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Axial-chiral mono- and biscarbene complexes of chromium containing the 1,1-binaphthyl skeleton have been obtained in both racemic and enantiopure forms in a one-pot reaction starting from lithiated 2,2-dimethoxy-1,1-binaphthyl (1) and hexacarbonyl chromium via the Fischer route. An X-ray structure analysis of the biscarbene complex 2 reveals that the biscarbene functionalization significantly increases the dihedral angle defined by the biaryl planes. The enantiopure complexes have been characterized by CD spectroscopy.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301108
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 33
    Electronic Resource
    Electronic Resource
    Evidence for Internal Ion Pair Formation upon Insertion of Reactive Alkene in the Zirconium-Carbon Bond of the cp2Zr(μ-C4h6)b(c6f5)3 Metallocene-Boron-Betaine Ziegler Catalyst System (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1261-1267 
    Details
    ISSN: 0009-2940
    Keywords: Single-component metallocene catalyst ; Olefin insertion ; Organometallic ions pairs ; (Alkene)metallocene complex ; Metallocene betaines ; C-C coupling ; Zirconium ; Homogeneous catalysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Treatment of the (butadiene)ML2 complexes 1 [ML2 = Cp2Zr (a), Cp2Hf (b), and (.-C5H4CH3)2Zr (c)] with B(C6F5)3 gives the 1:1 addition products (CH2CHCHCH2-B(C6F5_3)ML2 (3a-c). At -40°C the betaine complex 3a inserts one equivalent of methylenecyclopropane to give the regioisomeric insertion products 5a and 6a in a 60:40 ratio. These products exhibit the cyclopropylidene moiety in the α- and β-positions, respectively, relative to zirconium. The corresponding hafnocene complexes 5b and 6b are obtained in a 70:30 ratio starting from 3b. The reaction of 3(a-c) with allene gives a single insertion product (7a-c) in each case where the exo-methylene group is in the α-position to the metal center ([2,1]-insertion). The complexes 5-7 are chiral. They all exhibit a pronounced ·-interaction of the internal -C4H=C5H- double bond of the s̰-ligand chain with the metal center in addition to a metallocene/-C6H2-[B] ion pair interaction. The relative contributions of the cationic metallocene end of the dipolar complexes 5-7 are quite dependent on the steric and electronic properties of the respective metallocene units involved. This is revealed by a comparison to typical 13C-NMR parameters of the complexes 5-7 with a pair of suitable model complexes, namely the ethylene insertion product 4 into the betaine system 3a and its THF adduct 4.THF.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300914
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 34
    Electronic Resource
    Electronic Resource
    Tripod Ligands Containing a Mixed P/N/S Doner Set: Synthesis and Coordination Chemistry (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1279-1294 
    Details
    ISSN: 0009-2940
    Keywords: Tripodal ligands ; Aminolytic cleavage of oxetanes ; Tripod molybdenum compounds ; Mixed donor set ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The preparation of neopentane-based tripod ligands CH3C(CH2X)(CH2Y)(CH2Z( 3 (X = NR2, NHR; Y = PR2; Z = PR2, SR, S-) in a convergent manner is described. The procedure is based on the aminolytic cleavage of functionalized oxetanes CH3C(CH2OCH2)CH2R 1 by primary or secondary amines, leading to functionalized amino alcohols CH3C(CH2NHR)(CH2OH)(CH2R) or CH3C(CH2NR2)-(CH2OH)(CH2R) 2. The appropriate activation of the R (e.g. OR) and OH groups present in 2 allows for substitution vs. SR or PR2 donor functions. Depending on the nature of the groups present in each reaction step, various protection and groups present in each reaction step, various protection and deprotection steps have to be taken in the course of this type of preparation of the tripod ligands 3. By reaction with (CH3CN)3Mo(CO)3, ligands 3 form Mo(CO)4 derivatives 4 or Mo(CO)3 derivatives 5, depending on the reaction conditions. In compounds 4, the ligands are coordinated in a bidentate mode with the soft donor atoms (P, S) coordinated and the hard donor function playing the role of the dangling arm. In the trihapto bonding mode present in 5, all three donor functions, two soft (P, S) and one hard (NHR′, NR′2), are coordinated. The two types of coordination compounds may be interconverted: 4e (X = NMe2′ Y = PPh2, Z = SiPr) with a non-coordinating CH2NMe2 group is transformed into 5c upon photolytic decarbonylation. Under 1 bar CO at 20°C, 5c reverts to 4e. X-ray structure analysis of a series of compounds of types 4 and 5 reveals characteristics of the relevant conformational patterns. All compounds have been fully characterized by the standard analytical techniques (NMR, MS), as well as elemental analysis.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300917
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 35
    Electronic Resource
    Electronic Resource
    Neutral Gold(I) Complexes with Mixed Phosphorus LigandsDedicated to Professor Wolfgang Beck on the occasion of his 65th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1333-1338 
    Details
    ISSN: 0009-2940
    Keywords: Gold ; Gold(I) complexes ; Phosphinite complexes ; Phosphite complexes ; Configuration determination ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of compounds (R3P) AuMe with diphenylphosphinous acid Ph2P(O)H affords methane and neutral complexes of the type (R3P(O)Ph2 (1a: R = Me; 1b: R = Ph, lc: R = o-Tol). 1a, b are obtained in high yield, but the yield of lc is lower owing to a side-reaction which leads to a different product: Ph2P(OH)-Au-P(O)Ph2 (2). The crystal structure of 1a was determined by a single-crystal X-ray diffraction study. The compounds is a monomer with a linear P-Au-P′ axis and the phosphane and phosphinite ligands in a staggered conformation. In solution (CHCl3, CH2Cl 2/) compounds 1a-c undergo a ligand redistribution, establishing equilibria that involve ionic isomers of the type [R3P)2Au]+ [Au-(P(O)Ph2)2]-, which are readily identified through their NMR data. The analogous reaction of (R3P)b AuMe with dimethylphosphite (MeO)2P(O)H gives methane and the corresponding dimethylphosphites of the type (R3P)AuP(O)(OMe)2 (3a: R = Me; 3b: R = Ph; 3c: R= o-Tol). The crystal structure of 3b has also been determined. It features a linear structure with an eclipsed conformation of the ligands. In polar solvents (CHCl3, methanol) there is again an eqilibrium between neutral and ionic isomers, the latter comprising bis(phosphane)gold cations [(R3P)2Au]+ and {Au[P(O)-(OMe)2]2)- anions, as confirmed by NMR spectroscopy and mass spectrometry.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300925
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 36
    Electronic Resource
    Electronic Resource
    Regioselective Complexation of New Multiple Piperazine/Pyridine Ligands: Differentiation by 113Cd-NMR Spectroscopy (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1353-1359 
    Details
    ISSN: 0009-2940
    Keywords: 113Cd NMR ; Multidentate ligand ; Multinuclear metal complex ; Piperazine ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Eleven novel piperazine containing open-chain ligands L1-L11 were designed to offer symmetrical and asymmetrical complexation sites for metal ions and were synthesized by repetitive synthetic method. The divergent use of aromatic bishalomethyl and mono-N-alkylated piperazine compounds as spaces led toa series of long (up to M. W. = 836) oligomeric multidentate N-ligands. Due to the lack of solid state methods for structure analysis, an NMR technique using 113 Cd nucleus as a probe in solution state was utilised. 113 Cd chemical shifts were observed to be dependend on the coordination site and similar coordination sites in different ligands gave characteristically similar 113 Cd chemical shifts. As a result 113 Cd-NMR spectroscopy proved to be an excellent tool to distinguish between the structures of the different complexation sites on a nearly quantitative level.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300929
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 37
    Electronic Resource
    Electronic Resource
    Design of Self-Adapting N-Heteroaromatic Substituted Claw Ligands as E-/M+(E = P-Block Element, M = Main-Group Metal) Charge Spacers (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1365-1374 
    Details
    ISSN: 0009-2940
    Keywords: N ligands ; Chelates ; Coordination modes ; Ligand effects ; Structure-activity relationships ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Monoanionic bi- and tridentate ligand systems emulating the structural features of the well-known poly(pyrazolyl)borates are created by bridging heteroaromatic rings with formally negatively charged p-block elements. Their properties and versatility are exemplified by their complexes with main group metals. Due to their N(σ)-donating and π-interacting ability, as well as the flexibility of the substituent bonding, these ligand systems have the potential to adapt both geometrically and electronically to the coordination requirements of the complexed metal. Within these complexes, the heteroaromatic substituents operate as charge spacers between the formally anionic center and the metal cation without encapsulating either site. This provides possible applications in the creation of reactive soft/hard bimetallic reagents, the realization of multinuclear arrays, and the design of preorganized CVD precursors, particularly en route to III/V-semiconducting thin films.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301004
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 38
    Electronic Resource
    Electronic Resource
    Cyclic and Bicyclic Poly(phosphane)borane Cations (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1411-1416 
    Details
    ISSN: 0009-2940
    Keywords: Phosphane-boranes ; Boranes ; Phosphanes ; Umpolung, attempted ; Bond polarity ; Configuration determination ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reactions of (Me2S)BH2Br and (Me2S)BHBr2 with equimolar quantities of 1,2-bis(diphenylphosphanyl)ethene (1) or -benzene (2) lead to cyclic, cationic bis(phosphane)boranes [4[(1)BH2]+ Br-; 6: [(2)BH2]+ Br; 7: [(2)BHBr]+ Br-]. The Br counterions can be exchanged in metathesis reactions (e.g. with AgBF4 to afford 4a). The tritertiary phosphane bis[2-(diphenylphosphanyl)phenyl]phenyl-phosphane (3), reacts with (Me2S)BHBr2 to give bicyclic dicationic tris(phosphane)borane 8, [(3)BH]2+ Br-, which can be converted into the bis(hexafluorophosphate) 8a using NH4PF6. All compounds have been characterized by analytical and NMR-spectroscopic data. The crystal and molecular structures of 5 - 7 have been determined by single-crystal X-ray diffraction. The five-membered rings C2P2B have an envelope conformation and show no sign of electron delocalization. Attempts to deprotonate the B—H functions in 5 - 8 have not been successful. Clearly, the two (5 - 7) or three phosphonium centers (8) adjacent to the boron atom are not sufficient to induce an “umpolung” of the B—H group
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301009
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 39
    Electronic Resource
    Electronic Resource
    Reactivity of the Heavier Group-13 Monochlorides [{CH(SiMe3)2}2AlCl], InCl, TlCl, and of the Elements Ga and Hg Towards the Unsupported Ni-Ni Bond of [{(η5-Cp)Ni(PEt3)}2]  -  A Straightforward Synthetic Approach to the Synthesis of Mixed Main-Group/Transition-Metal Clusters Containing Unsupported Metal-Metal BondsDedicated to Prof. Dr. G Hutter on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1433-1440 
    Details
    ISSN: 0009-2940
    Keywords: Metal - metal bonds ; Insertion reactions ; Group-13 monochlorides ; Main-group elements ; Nickel ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The dinuclear compound [{(η5 - Cp)Ni(PEt3)}2] (1) containing an unbridged Ni-Ni bond reacts with the heavier group 13 monochlorides [{CH(SiMe3)2)2}AlIIICl], InCl, and TlCl by scission of the metal-metal bond. In the case of InCl and TlCl the chloro-bridged dimmers [{(η5-Cp)Ni(PEt3)2ECl2Ecl}2] (E = In 2, Tl 5) were formed. The Tl compound 5 is unstable and decomposes via disproportionation a and formation of the halogen-free Tl [III] compound [{(η5-Cp)Ni(PEt3)}3Tl] (6). 2 can be dehalogenated with activated magnesium to yield the halogen-free In [III] compund [{(η5-Cp}Ni(PEt3)}3In] (4). The Ga analogue of 4 and 6 [{(η5-Cp)Ni(PEt3)}3Ga] (7) is accessible by a conproportionation of 1 with Ga metal in refluxing THF. In contrast to InCl and TlCl the aluminium (III) monochloride [{CH(SiMe3)2}2AlCl] reacts with 1 by a ligand redistribution reaction and formation of the salt [{(η5-Cp)Ni(PEt3)2]+-[{CH(SiMe3)2]2AlCl]2-. (8). Elemental Hg or Mg amalgam show the same activity as elemental Ga towards 1 and insert into the Ni—Ni bond by forming the linear Hg-bridged complex [(n3-Cp)Ni(PEt3)]2Hg] (9). The molecular structures of 2, 4, 8, and 9 were determined by X-ray crystallography. The In atom in 4 has a distorted trigonal-planar configuration with the central In atom being surrounded by three [(n5-Cp)Ni(PEt3)] fragments. 4 represents the first Ni-In cluster containing exclusively unsupported In - Ni bonds, as well as the first carbonyl-free Ni - In cluster. On the basis of spectroscopic data the same structure is assigned to the Ga and Tl analogues of 4. The Ni—Hg—Ni arrangement in 9 is exactly linear, as determined by X-ray crystallography.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301013
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 40
    Electronic Resource
    Electronic Resource
    Hydrocarbon-Bridged Complexes, XL. Polyene-Bridged Iridium(III), Palladium(II), and Platinum(II) Complexes of Schiff Bases from α,ω-Polyene Dialdehydes and α-Amino Acids or o-AminophenolDedicated to Professor Dieter Seebach on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1467-1473 
    Details
    ISSN: 0009-2940
    Keywords: Schiff bases ; Polyene dialdehydes ; α-Amino acids ; Pantamethylcyclopentadienyl complexes ; P ligands ; Iridium ; Palladium ; Platinum ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Schiff bases 1—11 were synthesized from α-amino acids or o-aminophenol and crocetindialdehyde, 2,7-dimethyloctatrienedial, terephthalaldehyde, or β,β′ -p-phenylendiacroleine. The reactions of these Schiff bases with chloro-bridged complexes [(R3P)(Cl)M(η-Cl)]2 (M = Pd, Pt) and [(C5Me5)(Cl)Ir(°Cl)]2 gave the dinuclear complexes 12-31.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301018
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 41
    Electronic Resource
    Electronic Resource
    Enantioselective Catalysis. New Chiral Expanded Phosphanes Derived from Substituted Deltacyclenes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1495-1498 
    Details
    ISSN: 0009-2940
    Keywords: Deltacyclenes ; Deltacyclanes ; P-H addition reactions ; Chiral phosphanes ; Enantioselective catalysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The suitability of enantiomerically pure deltacyclenes as building blocks in the synthesis of expanded phosphanes was examined. Different substituted deltacyclenes were irradiated with diphenylphosphane and three bisphosphanyl derivatives. With these P—H addition reactions, new chiral deltacyclane-derived phosphorus ligands were synthesized. They were tested in the Rh-catalyzed asymmetric hydrogenation of (Z)-(ã)-N-acetamidocinnamic acid and in the Pd-catalyzed asymmetric allylation of 1,5-dimethylbarbituric acid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301023
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 42
    Electronic Resource
    Electronic Resource
    Masthead (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300101
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 43
    Electronic Resource
    Electronic Resource
    Photochemical reactions of transition metal organyl complexes with olefins, 17Part 16: Ref.. Light-Induced [6+2] Cycloadditions of Dienes to Tricarbonyl(η6-1,3,5,7-cyclooctatetraene)chromium(0) (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 9-12 
    Details
    ISSN: 0009-2940
    Keywords: Chromium ; Chromium(0) complexes ; Cyclooctatetraene complexes ; Photochemistry ; Cycloadditions ; Photochemical [6+2] cycloadditions ; Dienes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tricarbonyl(η6-1,3,5,7-cyclooctatetraene)chromium (1) yields upon UV irradiation in ether at 233 K with 2,3-dimethyl-1,3-butadiene (2) or 2-methyl-1,3-butadiene (3) by [6+2] cycloadditions the correspondingly substituted tricarbonyl(η6-bicyclo[4.2.2]deca-2,4,7-triene)chromium complexes 4, 5a and 5b. With ammonium cerium(IV) nitrate the organic ligand of complex 4, 9-isopropenyl-9-methyl-bicyclo[4.2.2]-deca-2,4,7-triene (6) is liberated. The complexes 4, 5a and 5b were characterised by IR and NMR spectroscopy, the ligand 6 by NMR spectroscopy.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300103
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 44
    Electronic Resource
    Electronic Resource
    A Structural Study of Selenobenzamides: Crystal Structures and Dynamic 13C NMR (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 49-54 
    Details
    ISSN: 0009-2940
    Keywords: 4-(p-Bromoselenobenzoyl)morpholine ; 4-[(p-(Dimethylamino)selenobenzoyl]morpholine ; Hindered rotation ; Hammett treatment ; Selenoamides ; Amides ; Selenium compounds ; Structure elucidation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The solid-state structures of (p-bromoselenobenzoyl)morpholine (2a) and [p-(dimethylamino)selenobenzoyl]morpholine (2b) were determined by X-ray diffraction. Both molecules show a flat selenoamide group. The larger contribution of resonance stabilization by the aromatic ring carrying the p-dimethylamino substituent is reflected by the smaller interplanar angle Θ between the aromatic ring and the selenoamide group [53.3(1)° vs. 81.1(1)°] and by the shorter length of the C=Se bond [1.824(5) Å vs. 1.840(3) Å]. The Gibbs free energy of activation of C-N bond rotation (ΔG≠rot) of five p-substituted (selenobenzoyl)morpholines was determined by dynamic 13C NMR. The activation barriers were found to range from 61.6 kJ/mol (X = NNMe2) to 75.1 kJ/mol (X = H). The ΔG≠rot values of the corresponding (thiobenzoyl)morpholines were found to be from 3.2 kJ/mol (X = NMe2) to 5.0 kJ/mol (X = H) lower. In both cases, ΔG≠rot showed an excellent linear Hammett correlation with s̰+p.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300108
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 45
    Electronic Resource
    Electronic Resource
    Synthesis and Characterization of Substituted Benzyl Zinc Derivatives - Molecular Structures of (tmeda) Li-CH (GeMe3)Ph, (tmeda)Zn(CH2Ph)2, (tmeda)Zn[CH(SiMe3)Ph]2, and (tmeda)Zn[CH(SiMe3)Ph]N(H)Si(SiMe3)3Dedicated to Professor Manfred Weidenbruch on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1499-1505 
    Details
    ISSN: 0009-2940
    Keywords: Lithium ; Zine ; Dibenzylzinc ; Tmeda complexes ; Heteroleptic alkylzinc amide ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of lithium phenyl(trimethylsilyl)methanide with phenyl(trimethylsilyl)methylzinc chloride-tmeda in the presence of tmeda yields the addition product, a bis(tmeda)-lithium dialkylchlorozincate. The elimination of lithium chloride leads to the formation of a tmeda adduct of bis[phenyl-(trimethylsilyl)methyl]zinc. The metathesis reaction of phenyl(trimethylsilyl)methylzinc chloride-tmeda with lithium tris(trimethylsilyl)silylamide allows the isolation of the corresponding heteroleptic tmeda complex of an alkylzinc amide. The metalation of phenyl(trimethylstannyl)methane with butyllithium yields the transmetalation product benzyllithium. From the metathesis reaction of this lithium base with anhydrous zinc(II) chloride in the presence of tmeda, the tmeda adduct of dibenzylzinc crystallizes. The molecular structures of (tmeda)Li—CH(GeMe3)Ph, (tmeda)Zn(CH2Ph)2, (tmeda)Zn[CH(SiMe3)Ph]2, and (tmeda)Zn[CH(SiMe3)-Ph[N(H)Si(SiMe3)3 are reported. Whereas lithium bonds in an η3-fashion, the zinc atom forms a σ(Zn—C) bond. The extremely wide Zn—N—Si angle in (tmeda)Zn[CH(SiMe3)-Ph[N(H)Si(SiMe3)3 of 157° is remarkable.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301024
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 46
    Electronic Resource
    Electronic Resource
    Unusual Dinuclear Hydridorhodium(III) Complexes Containing Bulky Phosphanyl(stibanyl)methanes as Chelating LigandsDedicated to Professor Luigi Venanzi on the occasion of his 70th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1529-1531 
    Details
    ISSN: 0009-2940
    Keywords: Rhodium ; Chelate complexes ; Hydrido complexes ; Bridging ligands ; P Ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mononuclear starting materials [Rh(η4-C8H12)(k2-P,Sb-iPr2PCH2SbR2)]PF6 (la, b) react with CF3CO2H in the presence of H2 to give the dinuclear hydridorhodium(II1) complexes [{RhH(k2-P,Sb-iPr2PCH2SbR2)]PF6 (2a, b) in almost quantitative yield. The X-ray crystal structural analysis of 2b (R = tBu) reveals a distorted octahedral geometry around the two metal centers with the two phosphanyl(stibanyl)methanes in a chelating and the two trifluoracetate ligands in a bridging coordination mode.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301028
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 47
    Electronic Resource
    Electronic Resource
    X-ray and Solution Structure of Inosine 5' -Monophosphate Coordinated to (Ethylenediamine)palladium(II).  - the Importance of Intramolecular Hydrogen Bonding (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1551-1555 
    Details
    ISSN: 0009-2940
    Keywords: Antitumor agents ; Nucleotides ; Palladium ; Hydrogen bonds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The compound [Pd(en)(5′-IMP-N7)2].11 H2O, where 5′-IMP = inosine 5′-monophosphate, crystallizes in the tetragonal space group P4322 with the unit cell parameters: a = b = 12.060(5) and c = 28.510(5) Å, V = 4147(3) Å3, Z = 4. A head-to-tail orientation with A configuration is observed for the nucleotides which are coordinated through the N(7) positions such that d[Pd-N(7)] = 2.053(8) Å. The sugar moieties exhibit anti orientations toward the purine bases while their pukkers adopt C(3)′-endo conformation. The overall conformation about the phosphate backbone is gauche+. Intramolecular hydrogen bonding is observed between the phosphates and the NH groups of the en ligand with a donor-acceptor distance of 2.88 Å. The coordination mode of the solid-state structure is shown to be identical to that observed by 1H-NMR spectroscopy in solution under slightly acidic conditions, where the N (l) positions of the nucleotides are protonated. The results are discussed in reference to closely related systems reported in the literature with emphasis on the importance of hydrogen bonding in such complexes.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301032
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 48
    Electronic Resource
    Electronic Resource
    Synthetic and Structural Studies of 1-Sila-2,5-diaryltetrazenes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1579-1583 
    Details
    ISSN: 0009-2940
    Keywords: Silatetrazenes ; Nitrogen-silicon ring systems ; Bissilylamines ; Silicon-29 solid state NMR ; Aryl azides ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction between aryl azides and lithiated aryl amines leads to tetrazenes 3 and 9 which contain a chain of four nitrogen atoms. Reaction with different halosilanes gives the cyclic silatetrazenes 10, 12, and 15 where substitutents on the silicon vary form alkyl to hydrogen and chlorine atoms. The structures of 10, 12, and 15 in the solid state are reported. Variation of the solvent and the Lewis acidity of the halosilane influence the ratio of silatetrazene to side products, bissilyated amines. These effects are studied for different halosilanes.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301105
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 49
    Electronic Resource
    Electronic Resource
    Bildung und Charakterisierung des Dinatrium-tetraphosphendiids (tBu3Si)NaP-P=P-PNa(SitBu3) und seines Dimeren (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 135-140 
    Details
    ISSN: 0009-2940
    Keywords: Synthesis ; Phosphorus ; Supersilyloligophosphides ; Crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of P4 in THF or DME with 2 R*Na (R* = SitBu3) at -78°C leads quantitatively to deep red THF or DME adducts of R*NaP-P=P-PNaR* (3). According to 31P NMR, the P4 skeleton 3 is cis-configurated. On the other hand, reaction of P4 in TBME with 2 R*Na at -78°C leads quantitatively to (R*NaP)4 (4), a [2+2] cycloadduct of 3, the Na4P8 skeleton of which according to X-ray structure analysis forms a double cube with four P atoms in the second layer and two P and two Na atoms in alternating positions in the first and in the third layer (the Na atoms are coordinated with donors). By resolving the THF adduct 3 in TBME (the TBME adduct of 4 in THF) the compound 4 (the compound 3) is rapidly formed under reversal of the P-P=P-P configuration by way of [2+2] cycloaddition (by way of [2+2] cycloreversion). 3 and 4 are sensitive to oxidation and to protolysis. With TCNE, 3 is oxidized to R*2P4 (bicyclic P4 skeleton), with CF3SO3H, 3 may be transformed into R*3P5Na2 X 4 THF or in (R*P3)3 and R*PH2.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300123
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 50
    Electronic Resource
    Electronic Resource
    Cyclopentadienyl Ring Metathesis with Organocalcium and Organopotassium Compounds (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 155-159 
    Details
    ISSN: 0009-2940
    Keywords: Cyclopentadienes ; Metathesis ; Potassium ; Calcium ; Main-group elements ; Sandwich complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cyclopentadienyl ring metathesis occurs between [Ca(C5Me5)2] and [Ln(C5H5)3] complexes in toluene to generate the mixed ring compounds [Ln(C5Me5)2(C2H5)] (Ln=1-La, 1-Nd). 1-Nd has been characterized with X-ray diffraction as a sterically crowded monomer. Only one ring is exchanged between [Ca(C5Me5)2(thf)x] and [La(C5H5)3(thf)x] in toluene to yield [La(C5Me5)C5H5)2 (thf)] (2). In reaction with [M(C5H5)2] (M=Sn, Pb, Mn), [Ca(C5M5)2(thf)x] yields the corresponding [M(C5Me5)2] complexes. K[C5Me5] reacts with [La(C5H5)3(thf)], [Sn(C5H5)2] and [Pb[C5H5)2] in toluene to yield the ring-exchanged products 2, [Sn(C5Me5)2], and [Pb(C5Me5)2], respectively.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300204
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 51
    Electronic Resource
    Electronic Resource
    Sterically Shielded Titanocene Enolates - Synthesis, Structure and Their Exceptional Stability towards Hydrolysis (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 195-199 
    Details
    ISSN: 0009-2940
    Keywords: Titanium ; Enolates ; Kinetics ; Enols ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of various sterically congested sodium enolates, generated by quantitative deprotonation of stable enols (of diphenylacetaldehyde in the case of 5), with dichlorotitanocene afforded a series of novel titanium enolates 1-5. The crystal structure of 1 could be determined. Due to the considerable steric shielding of the β,β-diaryl moiety, all the titanium enolates exhibit an oustanding stability towards hydrolysis, which increases with the higher steric demand of the substitutents at the C-C double bond. The kinetics of the hydrolysis, which is pseudo-first-order in THF/water (1 : 1) and acetonitrile/water (1 : 1), was investigated by UV spectroscopy. The pseudo-first-order rate constants measured in these solvent mixtures are in the range 6.4 · 10-4 s-1 〈 k1 〈 1.1 · 10-3 s-1. For comparison, the hydrolysis of 6, which should exhibit the usual sensitivity of titanium enolates towards hydrolysis, is about 1000 times faster.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300209
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 52
    Electronic Resource
    Electronic Resource
    (Triphenylphosphane)gold(I) Scrambling in a Hexanuclear Complex of Phenylene-1,2-bis(phosphane) (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 217-219 
    Details
    ISSN: 0009-2940
    Keywords: Gold compounds ; (Phosphane)gold(I) complexes ; Clusters ; P Ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Phenylene-1,2-bis(phosphane) reacts with two mole-equivalents of tris[(triphenylphosphane)gold(I)]oxonium tetrafluoroborate in dichloromethane at -78°C to give high yields of a hexanuclear complex {C6H4]P(AuPPh3)3]2}2+ · 2 BF-4 (1). The variable-temperature 31P{1H}-NMR spectra of the product in CD2Cl2 at - 80°C are compatible with a static structure featuring three Ph3PAu units associated with each of the two C6H4P2 phosphide functions, as derived from a clear doublet/quartet pattern. At 50°C in CDCl3, however, there is rapid intramolecular scrambling of these Ph3PAu units, which gives rise to a triplet/septet pattern with the J(P,P) value reduced to exactly one half of the value at the low temperature limit.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300212
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 53
    Electronic Resource
    Electronic Resource
    Synthesis and Properties of New Mixed-Halide Derivatives of Iron-Sulfide Dimers-Crystal Structure of (Et4N)2[Fe2S2Cl2Br2] (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 235-239 
    Details
    ISSN: 0009-2940
    Keywords: Iron-sulfur cluster ; Mixed halide ligands ; Magnetic properties ; Clusters ; Iron compounds ; Sulfur compounds ; Halogen compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis and characterization of the new mixed-halide clusters (Et4N)2[Fe2S2Cl4-nBrn] (n=2, 3), together with an improved synthesis of (Et4N)2[Fe2S2Br4] and the crystal and molecular structure of (Et4N)2[F2S2Cl2Br2], are reported here. The structure consists of [Fe2S2Cl2Br2] dianions, with a pseudo-tetrahedral symmetry around each iron atom. A disorder problem precludes precise identification of the locations of the chloride and bromide ligands. A syn (or anti) conformation is however considered to be most likely, for steric hindrance reasons and on the basis of Mössbauer data. The Mössbauer, magnetic susceptibility, cyclic voltammetry and UV/Vis properties of the new clusters remain similar to those of the parent single-type halide clusters. These new clusters are interesting precursors for complexes with mixed thiolate and non-thiolate coordination at the iron sites.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300216
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 54
    Electronic Resource
    Electronic Resource
    Synthesis, Structure, and Reactivity of Tetrakis(O,O-phosphorus)-Bridged Calix[4]resorcinols and Their Derivatives (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1715-1720 
    Details
    ISSN: 0009-2940
    Keywords: Calix[4]resorcinols ; Dioxaphosphocins ; Supramolecular chemistry ; Solid-state NMR spectroscopy ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis and characterisation of the reactive tetrakis (O,O-phosphorus)-Bridged calix[4]resorcinols 3 and 4 is described. Because of its poor solubility in common organic solvents, a solid-state NMR investigation of 3 (1H, 13C, 31P) was conducted. Reaction of 3 with MeMgl, Me3 SiMNe2, and HNMe2 furnished the η3γ3P-substituted cavitands 5 and 6. Oxidative addition reactions of 6 with the (H2N)2C(=O)/H2O2 (1:1) adduct, tetrachloro-o-benzoquinone (TOB), and hexafluoroacetone (HFA) led to the η4γ5P derivative 7, and to the η5γ5P derivatives 8 and 9. An X-ray crystal-structure determination of the tetrakis(O,O-phosphorus)-bridged calix[4]resorcinol 4 has been conduced. The framework displays the cone conformation; the chlorine atoms are directed inwards.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301124
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 55
    Electronic Resource
    Electronic Resource
    Tetra(amino)methanes: Implications of Their Structure and Reactivity Pattern for Hypothetical Carbon Nitride FrameworksDedicated to Professor George A. Olah. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1739-1744 
    Details
    ISSN: 0009-2940
    Keywords: Carbon nitride ; Tetra(amino)methanes ; Guanidinium salts ; Amination ; Conformation analysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Because of their possible role as model compounds for the structural units of carbon nitride C3N4, the preparation, structural chemistry, and some representative reactions of tetra(amino)methanes have been (re)investigated. In the crystal, C(NMe2)4 (1) has a molecular geometry close to D2a symmetry as proposed by theoretical calculations using state-of-the-art density functional methods. The coordination of the central carbon atom is distorted tetrahedral and the configuration of the nitrogen atoms is strongly pyramidal, as opposed to almost planar in the tetra(amino)silanes. Tetra(pyrrolidinyl)methane has a similar core structure, with all heterocyclic substituents in an envelop conformation flexible in solution. Tetra(piperidinyl)methane is more rigid in solution, owing to a more congested structure, with much higher inversion barriers for the six-membered rings. Hydrolysis of 1 leads to MezNH and hexamethylguanidinium hydroxide, and treatment of 1 with HAuCl4(aq) affords crystalline [C(NMe2)3]4 AuCl4- the structure of which has also been determined. Compound 1 is a strong nucleophile and can be used as an aminating agent, converting e.g. halosilanes into dimethylaminosilanes, with the guanidinium cation as the leaving group. The experimental results are discussed in the light of recent predictions regarding bulk carbon nitrides.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301206
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 56
    Electronic Resource
    Electronic Resource
    Halogenation of 1-Ethoxy-1-oxophosphindolin-3-one, a Potential Phosphaindigo Precursor (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1765-1770 
    Details
    ISSN: 0009-2940
    Keywords: Phosphinic acid ; Phosphaindole bromination and chlorination ; Layer structure ; Hydrogen bonds ; Bromine-bromine interaction ; Phosphorus heterocycles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The bromination of 1-ethoxy-1-oxophosphindolin-3-one (1) with two equivalents oi bromine occurs with elimination of hydrogen bromide and ethyl bromide, providing 2,2-di- bromo-1-hydroxy-1-oxophosphindolin-3-one (4) in high yield. In the presence of triethylamine this process leads to 2,2-dibromo-1-ethoxy-1-Oxophosphindolin-3-one (3) instead. Triethylamine deprotonates 4, providing the solid triethylammonium salt 5. Silylation of 4 with chlorotrimethylsilane leads to the trimethylsilyl ester 6. Monobromination in a two-phase reaction allows the isolation of a mixture of isomers of 2-bromo-1-ethoxy-1-oxophosphindolin-3-one (2a, b). Chlorination with chlorine furnishes 2,2-dichloro-1-ethoxy-1-oxo-phosphindolin-3-one (7). The new compounds 2-7 were characterized analytically and spectroscopically (EI-MS, 1H, 13C and 31P NMR). The crystal structure of acid 4 was determined by X-ray diffraction. Solid 4 consists of aryl stacks connected by chains of P—OH…O==P hydrogen bonds and secondary Br…Br contacts.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301210
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 57
    Electronic Resource
    Electronic Resource
    Kinetics and Mechanism of Substitution Reactions of cis-[PtMe2(dmso)2] with Pyridine (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1791-1799 
    Details
    ISSN: 0009-2940
    Keywords: Platinum substitution ; Metal-carbon bonds ; trans-Labilization ; Kinetics ; Activation parameters ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The substitution reactions of cis-[PtMe,(dmso),] with pyridine (py) to produce cis-[PtMe2py2] in toluene proceeds in two steps. In the absence of added dimethylsulfoxide (dmso), these steps can not be separated due to the rate constants being very similar. In the presence of added dmso, the rate of the first step, the formation of the monopyridine complex is retarded, which is indicative of a dissociative mechanism. A parallel associative reaction path with pyridine could also be observed. This pathway is independent of the concentration of added dmso. Above a 40-fold excess of dmso, the dissociative pathway is suppressed and only the associative reaction occurs. A plot of Kobs vs the pyridine concentration for this pathway is linear at low [py], but shows a saturation at high [py]. This suggests that the reaction occurs via the formation of a precursor-complex, for which the formation constant was found to be 0.32 · 0.03 M-1. The volume of activation at a high pyridine concentration is -11.4 · 0.8 cm3 mol-1, which indicates that the ligand interchange process is of the associative type. The second step, the formation of the bispyridine complex, can clearly be separated from the first reaction step. This step occurs via a dissociative mechanism, as demonstrated by the decrease in kobs with increasing pyridine concentration. The dissociation of dmso was characterized by a rate constant of (8.1 · 0.9).10-45-1 at 25°C, ·H = 116 ·9 kJ mol-1 and AS. = 86 · 29 JK-1 mol-1. At higher pyridine concentrations evidence for a parallel associative reaction was found, for which the rate constant is (1.3 · 0.2).10-3 M-1S-1 25°C. The results are discussed in reference to available literature data.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301214
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 58
    Electronic Resource
    Electronic Resource
    Synthesis and Properties of Me2Ge-Bridged Arenes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 421-424 
    Details
    ISSN: 0009-2940
    Keywords: Macrocycles ; Germanium ; UV/Vis spectroscopy ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Linear and cyclic oligomers of Me2Ge-bridged π-systems have been obtained by the reaction of carbo- and heterocyclic anions and dianions with Me2GeCl2. The spectroscopic properties of the new compounds are compared with analogous carbon- and Me2Si-bridged π-systems.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300318
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 59
    Electronic Resource
    Electronic Resource
    P/O Ligand Systems: Synthesis, Reactivity, and Structure of Tertiary o-Phosphanylphenol Derivatives (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 431-431 
    Details
    ISSN: 0009-2940
    Keywords: o-Phosphanylphenols ; P,O hybrid ligands ; P asymmetry ; C,O-dilithium reagents ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300320
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 60
    Electronic Resource
    Electronic Resource
    Masthead (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300401
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 61
    Electronic Resource
    Electronic Resource
    Molybdenum-Catalysed and -Mediated Cycloaddition Reactions: Efficient Synthesis of Complex Products from 1-Oxa-1,3-dienes and Cyclotrienes or -tetraenes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 453-462 
    Details
    ISSN: 0009-2940
    Keywords: Cycloadditions ; Catalysis ; 1-Oxa-1,3-dienes ; Molybdenum ; stereoselectivity ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Molybdenum-mediated [6 + 2]-cycloaddition reactions of unsaturated ketones to cyclotri- or -tetraenes, e.g. cyclohepta-1,3,5-triene or cyclooctatetraene, proceed under very mild conditions, in high yields and with excellent stereoselectivity starting from the appropriate dicarbonylbis[π4-(1-oxa-1,3-diene)]molybdenum complexes. The stereochemistry of the product arising from the reaction of dicarbonylbis[π4-(5-methylhex-3-en-2-one)]molybdenum with cyclohepta-1,3,5-triene allows one to deduce a stepwise mechanism for this addition. The reactants are fused, as would be expected from an exo-type approach, thus indicating an intermolecular attack of the cycloheptatriene. Tungsten oxadiene complexes are effective in analogous reactions at somewhat reduced reaction rates. Catalytic cycloadditions are observed in several cases when 1-5 mol% of the highly reactive dicarbonylbis[π4-(R-(+)-pinocarvone)]molybdenum is employed as the catalyst. Cycloadducts are formed diastereospecifically in most cases. When cyclooctatrienes are employed as reactants, a sequence of electrocyclization of the triene and subsequent [4 + 2]-cycloadditon occurs with high selectivity and efficiency, leading to a pentacyclic ketone. The product structure reveals an endo-type approach of the polyene in this case.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300404
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 62
    Electronic Resource
    Electronic Resource
    Tris-Chelating Oxygen Ligands: New Synthetic Routes to Sterically Demanding Ligands (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1223-1229 
    Details
    ISSN: 0009-2940
    Keywords: Tripodal ligands ; O ligands ; Cabalticenium cation ; Sodium coordination ; Ligand profile ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The lithium and sodium compounds A[P(O)R2] (A+ = Li+, Na+; R = OPh, OiPr) have been prepared in situ from Hp(O)R2 and butyllithium or sodium hydride. They react with the cyclopentadienyl complexes [(C5H5)MI2(CO)] (M = Co, Rh), [(C5Me5)CoCl2]2, and [(C5H5)CoI2]n to yield alkali metal salts AL of tridentate oxygen ligands (A+ = Li+, Na+; L- = [(C5R′5]M{P(O)R2}3]-, R′ = H, Me; M = Co, Rh; R = OPh, OiPr) (2). For the ligand LCo, OPh = [(C5H5)-Co{P(O)(OPh)2}3]-, an alternative synthesis has been developed, starting from [(C5H5)2Co]PF6. The structure of the sodium salt NaLCo, OPh (2d) has been determined by X-ray diffraction. The ligand LCo, Oph-, with a cone angle TH of about 200°, completely blocks one half of the coordination sphere around the sodium centre. The ligand profile has been calculated to allow appraisal of the angular encumbrance of the ligand.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300909
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 63
    Electronic Resource
    Electronic Resource
    Synthesis, Redox Chemistry, and Mixed-Valence Phenomena of Cyanide-Bridged Dinuclear Organometallic Complexes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1241-1252 
    Details
    ISSN: 0009-2940
    Keywords: Organometallic complexes ; Cyanide bridges ; Structure elucidation ; Isomerizations ; Oxidation ; Mixed valent compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 21 new organometallic complexes of the type M-Cn-M′ containing the building blocks M, M′ = (CO)5Cr, (CO)5Mo, (CO)5W, Cp(CO)2Mn, Cp(CO)2Fe, Cp(CO)(CN)Fe, Cp(dppe)Fe, Cp(PPh3)2Ru, Cp(PPh3)Ni, and (PPh3)2Ag were obtained from the reagents M-Cn and M-X (X = leaving group). Among them are five pairs of linkage isomers M-CN-M′/M-NC-M′. Structure determinations of (CO)5Cr-CN-M′ with M′ = Fe(dppe)Cp, Ni(PPh3)Cp, Ag(PPh3)2 and of (CO)5Cr-NC-Fe(dppe)Cp have proved their identity and the linkage isomerism. Systematic variations of the v(CN) and v(CO) IR bands allow as assessment of the relative electron pair acceptor strengths of the building blocks M and M′ and a reliable identification of the individual linkage isomers. All dinuclear complexes are redox-active, showing at lease one reversible oxidation. The redox potentials are characteristically dependent upon the nature of the building blocks M and M′ and upon the orientation of the cyanide link (CN vs. NC), 6 oxidized complexes of the type [M-Cn-Fe(dppe)Cp]+ were prepared chemically and isolated as PF6 or BF4salts. The molecular structure of [(CO)5Cr-CN-Fe(dppe)Cp]BF4 is not significantly different from those of the corresponding neutral Cr-CN-Fe or Cr-NC-Fe complexes. Upon oxidation the v(CN) band of the complexes shifts to lower wavenumbers and becomes much more intense. The oxidized complexes show the paramagnetism due to one unpaired electron. They give rise to very intense metal-to metal charge-transfer bands in the near infrared region whose position was found to be characteristically dependent on solvent polarity of [(CO)5Cr-CN-Fe(dppe)Cp]BF4. A semiquantitative treatment of the optical and electrochemical measurements shows that the electron delocalization and metal-metal interaction in the oxidized dinuclear complexes is significant and that they belong to the class-II mixed-valence systems.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300912
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 64
    Electronic Resource
    Electronic Resource
    A Density Functional Study of the Systems [MH3(PMe3)4]+ (M = FE, RU, OS) (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1273-1277 
    Details
    ISSN: 0009-2940
    Keywords: Transition metal ; Complexes of the iron triad ; Density functional calculations ; Relativistic effects ; Hydrido complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The structures and relative energies of various isomers of [FeH3(PMe3)4)+ (1), [RuH3(PMe3)4]. (2) and [OsH3(PMe3)4]. (3) have been studies by density functional theory. The stereoisomers considered are derived from a tetrahedral (T), square planar (P), and C2v-butterfly (C) arrangement of the phosphane ligands. For the latter two, classical trihydride (I) and nonclassical hydride/dihydrogen (II) geometries have been considered 1 and 2 prefer coordination mode II, whereas 3 favours coordination mode I. This trend is explained by relativistic effects. For Fe and Os, the C and T type structures are preferred over a P geometry. for Ru, the C and P structures are close in energy, and the T arrangement represents the highest energy isomer.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300916
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 65
    Electronic Resource
    Electronic Resource
    Transition-Metal-Substituted Acylphosphanes and Phosphaalkenes, 35 Unprecedented Coupling of a Transition-Metal Carbyne and a Methylene Phosphane Moiety - Structure of [Tp'(CO)2W=CP=C(NEt2)2] [Tp = HB (3,5-Me2HC3N2)3] (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1305-1308 
    Details
    ISSN: 0009-2940
    Keywords: Carbyne complexes ; Phosphaalkenes ; Molybdenum ; Tungsten ; . interactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Condensation of [Tp](CO)2 Mčl] [1: M = Mo; 2: W; Tp] HB (3,5-Me2HC2N2)3] with the inverse phosphaalkenes Me3 Sip=C(NR2)2 (3a: R = Me; 3b: Et) affords the novel phosphaalkenyl carbyne complexes [Tp](CO)2M.C-P=C(NR2)2] (a, b) (M = Mo; R = Me, Et) and 5a, b (M = W; R = Me, Et), which have been characterized by IR, 1H-, 13C- and 31P-NMR spectroscopy. In additon, the molecular structure of 5 has been elucidated by a single-crystal X-ray structure determination.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300920
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 66
    Electronic Resource
    Electronic Resource
    Palladium  -  Catalyzed Reactions, 1 Palladium-Catalyzed Enantioselective Hydrophenylation and Hydrohetarylation of Bicyclo[2.2.1]Hept-2-ene: Influence of the Chiral Ligand, the Leaving Group, and the Solvent (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1327-1331 
    Details
    ISSN: 0009-2940
    Keywords: Asymmetric catalysis ; Hydroarylation ; Palladium ; P-N ligands ; Heterocycles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The use of optically active biaryl bisphosphanes 10-12, a diphenylphosphanylphenyloxazoline 8, and a (β-N-sulfonyl-aminomethyl)bisdiphenylphosphane 7 as ligands in the Pd-catalyzed Heck-type hydroarylation of norbornene (1) with phenyl 2 and various hetaryl derivaties 3-5 leads exclusively to the formation of exo-2(het)arylnorbornanes 6 with asymmetric inductions of up to 86.4% ee. In addition to an investigation into the effects of different chiral ligands, a systematic study has been made of the influence of various (het)aryl compounds, leaving groups, and solvents on the chemical and optical yields of this reductive arylation.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300924
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 67
    Electronic Resource
    Electronic Resource
    Synthesis and Structural Characterization of Mixed-Ligand Oxorhenium(V) Complexes Containing Bidentate Dithioethers and Monothiolato Ligands (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1343-1347 
    Details
    ISSN: 0009-2940
    Keywords: Rhenium ; Technetium ; Radiop[pharmaceuticals ; Mixed-ligand complexes ; sulfur ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Neutral oxorhenium(V) complexes with dithioether ligands of the general formula [ReOX3(RS[CH2]2SR)], × = Cl, Br, R = nBu, Et, Bzl were synthesized. Ammonium perrhenate reacts in concentrated hydrochloric acid with dithiaalkanes (RS[CH2]2SR, R =nBu, Et, Bz) dissolved in glacial acetic acid to give octahedral complexes of the type [ReOCl3(RS[CH2]2SR)] (1a-c). In concentrated hydrobromic acid, nBu-S(Ch2)2S-nBu leads to the corresponding tribromo complexes (2). The X-ray structure of shows a distorted octahedron with facial coordination of the bromide ligands. The sulfur atoms are cis coordinated to the terminal oxygen. Dissolution o f1a (R = nBu) in methanol leads to the substitution of the chloride trans to the oxo ligand by a meth oxy group. The resultant complex [ReOCl2(MeO) (nBu-S[CHL2]2S-nBu)] (3) is stable and can be isolated from methanolic solution, but changes to the μ-oxo-bridged dirhenium complex μ-oxobis[dichloro(5,6-dithiadidodecane)oxorhenium(V)] (4) when dissolved in other organic solvents. 1a reacts with an excess of benzenethiol by substitution of two chlorides to give the mixed-ligand complex bis(benzenethiolate)chloro(5,8-dithiadodecane)oxorhenium(V) (5a). The related 4-methylbenzenethiolato complex 5b was synthesized starting from the μ-oxo complex 4. X-ray crystal structure determination of 5b shows the equatorial arrangement of the sulfur atoms. The trans position to the oxygen atom is occupied by a chloride ion.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300927
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 68
    Electronic Resource
    Electronic Resource
    Editorial (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. i 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301003
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 69
    Electronic Resource
    Electronic Resource
    Diastereoselectivity in the Reaction of RCH2C[CH2P (Ar)(Lr)]3 with Electrophiles: Enhancement of Diastereoselective Control by η3-Coordination in {RCH2C[CH2P(Ar)(Li)3}Mo(Co)3 (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1379-1392 
    Details
    ISSN: 0009-2940
    Keywords: Chiral tripod ligands ; Tripod Mo(CO)3 compounds ; Diastereoselective synthesis ; Separation of diastereomers ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Following a procedure developed for H3CC[CH2P(Ph)2]3 (1a) as the starting compound, various tripod ligands RCH2C[CH2P(Ar)2]3 (1) have been transformed into the trilithiotriphosphides RCH2C[CH2P(Ar)(Li)]3 with various electrophiles R′  -  Hal leads to the two diastereomers of RCH2C[CH2P-(Ar)(R)]3 (6) with an (RRR/SSS : RRS/SSR) ratio close to the statistical value of 1:3, except when Ar=Ph and R′=Bzl, where the RRS/SSR diastereomer is obtained almost exclusively. In contrast, the reaction of [RCH2C[CH2P(Ar)(Li)[3]-Mo(CO)3 (4) with electrophiles R′  -  Hal tends to favour the formation of the homochiral RRR/SSS diastereomers. The triphosphide coordination compounds 4 are available by two different routes: either the complexes (RCH2C[CH2P-(Ar)(H)]3Mo(CO)3, obtained from 2 and (CH3CN)3Mo(CO)3, are deprotonated by MeLi, or the trilithiotriphosphides RCH2C[CH2P(Ar)(Li)]3 are reacted with (CH3CN)3Mo(CO)3 to produce 4 in high yields. The ration in which the two diastereomeric forms of 5 are obtained depends on the nature of the electrophile: the greatest diastereomeric discrimination is obtained for Ar=Ph, R=Ph, R′=Bzl, where the homochiral relative to the RRS/SSR pair. Two-dimensional NMR spectra and simulations of one-dimensional spectra are used to ascertain the diastereomeric excess in each case. X-ray analyses of three compounds of type 5 (5d, Ar=Ph, R=H, R′=Ph, R′=Bzl) indicate the remarkable conformational stability of the tripod metal scaffolding, with the conformations observed for these three compounds in three different solid-state environments being closely similar, even with respect to the torsional arrangement of the phosphorus-bound benzyl groups.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301006
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 70
    Electronic Resource
    Electronic Resource
    Gold(1) Complexes of Ketiminophosphanes and -phosphane Sulfides (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1423-1426 
    Details
    ISSN: 0009-2940
    Keywords: Gold ; Gold(I) complexes ; (Imine)gold(I)complexes ; Ketiminophosphanes ; (Ketiminophosphane)gold(I) complexes ; Ketiminophosphane sulfides ; (Ketiminophosphanesulfide)gold(I) complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reactions of chloro(dimethyl sulfide)gold(I) with equivalent quantities of the ketiminophosphane diphenyl(diphenylmethyleneamino)phosphane (1a) or its sulfide (1aS) lead to high yields of stable, crystalline 1 : 1 complexes with AuCl units attached to the phosphorus and sulfur atom, respectively. Tris(diphenylmethyleneamino)phosphane (1c) gives the related complex (Ph2C=N)3PAuCl with the gold atom also selectively P-bound. Bis(diphenylmethyleneamino)phenyl-phosphane (1b) could not be used because of its limited stability. Single-crystal X-ray diffraction studies have shown that there is no auxiliary coordination of the metal center by the imino functions of the ligands. The geometry of the P/S—Au—Cl moieties deviates only very slightly from linearity. The angle at the sulfur atom in (Ph2C=N)Ph2PSAuCl is very small [94.30(3)°], but despite of the resulting rather open coordination there are no discernible intra- or intermolecular contacts in the lattice. Such contacts are also absent with (Ph2C=N)Ph2PAuCl and (Ph2C=N)3PAuCl owing to the bulk of the ligands. The 1 : 1 complexes do not react with an excess of (Me2S)AuCl. This finding, and the molecular structures of the 1 : 1 complexes, show very consistently that both phosphane and sulfide donors are far superior as ligands for gold(I) as compared to ketimine donor molecules.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301011
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 71
    Electronic Resource
    Electronic Resource
    Pyrazolate-Based Oligonuclear Copper and Silver Complexes with N/S Coordination SpheresDedicated to Prof. Dr. Gottfried Huttner on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1441-1447 
    Details
    ISSN: 0009-2940
    Keywords: Pyrazolate complexes ; Bridging ligands ; Copper ; Silver ; N,S-Donor Ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of pyrazole-based potential ligands bearing thioether substituents in 3- and 5-positions of the heterocycle was synthesized [3,5-bis(RSCH2)-pyzH R=Ph (1aH), PhCH2 (1bH), iPr (1cH), tBu (1dH)]. These ligands afford oligonuclear Cu1 and Ag1 coordination compounds [LCu]x (2a-c, L = 1a - c) and [LAg]x (3a-d, L = 1a-d), respectively. The single crystal X-ray analysis of 3c shows the presence of trimeric planar arrays of N,N′-bridging pyrazolates and linear coordinated silver ions, with each two of the trinuclear moieties being linked by two unsupported short intermolecular Ag…Ag contacts [3.041(1) Å]. Molecular-weight determinations for 2a (THF) and 3c (toluene) indicate that hexanuclear entities are preserved in solution. Starting from 1bH the CuII complex [(1b)2Cu2](BF4)2 (4) was synthesized. According to an X-ray crystal structure analysis it consists of dinuclear molecules with two bridging pyrazolates, distorted square planar N2S2 coordination spheres for Cu11 and an axially bridging tetrafluoroborate. Magnetic susceptibility data reveal an antiferromagnetic exchange (J = -206 cm-1) that is among the highest found for doubly pyrazolate bridged dicopper(II) complexes, which is rationalized on the basis of the rather symmetric dinuclear core of 4. The irreversibility of the electrochemical reduction and oxidation processes for the CuII and CuI compounds, respectively, is explained by the inability of the respective coordination framework to adapt to different geometric preferences.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301014
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 72
    Electronic Resource
    Electronic Resource
    Hydrocarbon-Bridged Metal Complexes, XLI. Addition of Aniline Tricarbonyl Chromium Complexes to the Cyclohexadienyl Ligand of (μ5-C6H7)M(CO)3+ (M = Fe, Ru)Dedicated to Professor Hanns-Peter Boehm on the occasion of his 70th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1475-1477 
    Details
    ISSN: 0009-2940
    Keywords: Iron ; Ruthenium ; Chromium ; Carbonyl complexes ; N-(2,4-Cyclohexadienyl)aniline ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The addition of aniline tricarbonyl chromium complexes (η6-C6H4(R)NHR1)Cr(CO)3 (R=H, CH3; R1=H, CH3) to [(n5-C6H7)M(CO)3]+ (M=Fe, Ru) gives the heterobimetallic ligand-bridged complexes (OC)3Cr(n6-C6H4(R)N(R1)C6H7-n4)M(CO)3. The structure of (OC)3Cr(n6-C6H4(CH3)N(H)-C6H7-n4)Ru(CO)3 has been determined by X-ray diffraction.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301019
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 73
    Electronic Resource
    Electronic Resource
    New Phosphorus Heterocycles by Rearrangement of a [1,4-Bis(trimethylsilyl) η8-cyclooctatetraene-1,3,5-triphospha-7-hafnanorbornadiene ComplexDedicated to Professor C. G Kreiter on the occasion o f his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1491-1494 
    Details
    ISSN: 0009-2940
    Keywords: Phosphorus heterocycles ; Phosphaalkynes ; Triphospha Dewar benzenes ; Triphosphacyclobutadiene ; 1,4-Bis(trimethylsilyl)-η8-cyclooctatrienehafnium complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: [1,4-Bis(trimethylsilyl)-n8-cyclooctatetraene]-2, 4, 6-tri-tert-butyl-1, 3, 5-triphospha-7-hafnanorbornadiene (3) rearranges nearly quantitatively to the corresponding 3,5,6-tri-tert-butyl-1,2,4-triphospha-7-hafnanorbornadiene complex 5 upon heating at 70°C. Treatment of complex 5 with trimethylphosphane at 50°C induces the displacement of di-tert-butylacetylene to give the new (n4-triphosphacyclobutadiene)hafnium complex 7, the crystalstructure of which has been determined by X-ray analysis. From complex 5 3,5,6,-tri-tert-butyl-1,2,4-triphospha Dewar benzene (6) can be synthesized by a redox reaction with hexachloroethane.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301022
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 74
    Electronic Resource
    Electronic Resource
    Dirhenium Complexes with S2CPR3 Bridges Donating Four and Eight Electrons  -  X-ray Structures of [Re2(CO)8{μ-η1;η1-S2CPCy3}] and {Re2(CO)6{μ-η3;-S2CPCy3}] and [Re2(CO)6{μ-η2; η3-S2CPCy3}] (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1507-1511 
    Details
    ISSN: 0009-2940
    Keywords: 1,1-Dithiolate ; Rhenium ; Carbonyl complexes ; Bridging ligands ; Bimetallic complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of fac-[Re(CO)3(S2CPR3)Br] with [Rc(CO)5]- affords the dinuclear octacarbonyl compounds [Re2(CO)8(μ-S2CPR3)] (3a—b), which have been isolated and characterized by spectroscopic methods. An X-ray crystal-structure determination of the derivative 3a (R=Cy) shows that the S2CPCY3 ligand acts as an η1(S);η1(S′) bridge donating two electrons to each metal atom of a symmetrical (CO)4Re—Re(CO)4 unit. This unit is presumably formed through a concerted process involving carbonyl/sulfur exchange in the nonsymmetrical octacarbonyl (CO)3(S2CPR3)Re—Re(CO)5 generated after the coupling of the bromo derivative with the carbonyl anion. Complexes 3a—b can be obtained more directly by adding S2CPR3 to [Re2(CO)8(μ-H)(μ-CH=CHnBu)], which is formed by irradiation of Re2(CO)10 with 1-hexene. Hydride addition to the central carbon atom of the S2CPR3 ligand of 3a-b occurs with loss of PR3, to give the anion [Re2(CO)8(μ-S2CH)]- which may be isolated as a salt with the PPN+ cation. The octacarbonyl compounds 3a-b can be converted into hexacarbonyl complexes [Re2(CO)6(μ-S2CPR3)] (5a-b) by heating in toluene or octane at reflux temperature. According to an X-ray crystal-structure determination of the derivative 5a (R=Cy), the loss of one carbonyl ligand from each rhenium atom is accompanied by the rearrangement of the S2CPR3 ligand which changes its bonding mode from η1(S);η1(S′) donating four electrons to η3(S,C,S′);η2(S,S′) donating eight electrons.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301025
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 75
    Electronic Resource
    Electronic Resource
    Interactions in Molecular Crystals, 118. The Sodium(benzo-15-crown-5) Salt of 2, 6-Di(tert-butyl)-4-methylphenol, a Sodium Phenolate with an Extremely Short Na+…O- Distance: Structure and Density Functional Calculations (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1533-1537 
    Details
    ISSN: 0009-2940
    Keywords: 2,4,6-Trialkylphenol deprotonation ; Sodium/benzo-15-crown-5 solvation ; Crystal structure ; Density functional calculation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The structure of crystals, isolated in low yield, from the attempted metallation of diphenylmethane in tetrahydrofuran solution containing benzo-15-crown-5 at a sodium metal mirror is determined, surprisingly, to be the sodium (benzo-15-crown) salt of 2,6-di(tert-butyl)-4-methylphenol, an antioxidative stabilizer to prevent ether peroxide formation. The structure of the solvent-shared contact ion pair (monoclinic P21/n, Z = 4, R1 = 0.06) proves a strong Na+…O- interaction at the extremely short distance of only 216 pm, a sixfold O-coordination of the Na+ cation in a pentagonal pyramid, and a hemispherical distortion of the crown ether. Density functional calculations at the B3LYP/6-31G* level, based on the structural data, reproduce, within a one-dimensional hypersurface approach, the rather short Na+…O- distance, and predict Mulliken charges of +0.32 for Na′ and -0.71 for 0-, as well as a considerable polarization of the trialkyl phenolate anion.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301029
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 76
    Electronic Resource
    Electronic Resource
    Palladacycles as Reactive IntermediatesDedicated to Prof. Dr. Dietrich Döpp on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1567-1578 
    Details
    ISSN: 0009-2940
    Keywords: Metallacycles ; Palladium catalysis ; Domino reactions ; Polycyclic ring systems ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Palladacycles are discussed as the key intermediates of some important preparative ring forming reactions; their reactivity depends strongly on the ring size. The existence of 5-membered palladacycles, and even 4-membered palladacycles, is now firmly established, whereas the knowledge of 6-membered and larger palladacycles is based mainly on mechanistic considerations. The role of 5-membered palladacycles as catalysts is described briefly.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301104
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 77
    Electronic Resource
    Electronic Resource
    Olefin Carbonylation Catalysis with Cationic Palladium Complexes: Selectivity and Possible Intermediates (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1557-1565 
    Details
    ISSN: 0009-2940
    Keywords: Carbonylations ; Alkenes ; Palladium ; Asymmetric catalysis ; P and N ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Palladium complexes L2PdX2 containing various group Va ligands and weakly coordinating anions are active catalysts for the carbonylation of olefin substrates. These catalytic systems, though gaining significance in industry for the synthesis of polyketones, are normally characterised by a low chemoselectivity. This derives from the numerous possibilities for initiation and termination reactions which lead to different catalytic cycles and from facile multiple alternating insertion reactions of olefins and carbon monoxide. Based on experiments carried out under conditions of low selectivity and on previously published data, the factors involved in the control of the regio-, chemo- and stereoselectivity for those reactions are discussed, taking current ideas and model studies involving the above palladium complexes into consideration.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301103
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 78
    Electronic Resource
    Electronic Resource
    Dichlorogermylene-Alkyldichlorophosphane Reactions Revisited: Characterisation of Bis(trichlorogermyl)phosphanes, Trichlorogermyldiphosphanes, and Ge-P Heterocycles (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1611-1618 
    Details
    ISSN: 0009-2940
    Keywords: Alkyldichlorophosphanes ; Insertions ; Carbene homologues ; Germanium ; Phosphonium germanate(II) ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reactions of alkyldichlorophosphanes 1 (RPCl2; R = tert-butyl: 1a, R = isopropyl; 1b, R = 1-adamantyl: 1c) with the germanium dichloride dioxane complex were followed by 31P NMR. Depending on the organic substituents and the reaction conditions, mixtures of trichlorogermylphosphanes RP(GeCl3)2 4a-c, RPHGeCl3 5a-c, diphosphanes R(H)PP(H)GeCl3 6a-c, R(Cl)PP(H)GeCl3 7a, b cyclophosphanes, and Ge-P heterocycles such as triphosphadigermolanes (RP)3(GeCl2)2 8a, b and tetraphosphagermolane (RP)4)GeCl2 10b are formed. As a further unexpected byproduct of the reaction of 1a with GeCl2-dioxane, a small amount of tri-tert-butyl(trichlorogermyl)cyclotetraphosphane 9a was isolated. From the reaction of 1c with two equivalents of GeCl2-dioxane, separation from byproducts 5c and 6c by crystallisation furnished colourless crystals of 4c (R = 1-adamantyl) as the first pure organylbis(trichlorogermyl)phosphane. Surprisingly, the reaction of isoprophylphosphane with germanium tetrachloride, intended to prepare 5a, led to crystalline isopropylphosphonium trichlorogermanate(II) 11. The structures of molecular 4c and 9a and ionic 11 were determined by X-ray crystallography.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301109
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 79
    Electronic Resource
    Electronic Resource
    Synthesis and Structure of Trimethyllead Niobocene DihydrideDedicated to Professor Jörg Lorberth on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1629-1631 
    Details
    ISSN: 0009-2940
    Keywords: Lead ; Niobium ; Hydrides ; Group 5 ; Group 14 ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of niobocene trihydride [Cp2NbH3] with ClPbMe3 in the presence of amine affords the plumbido dihydride complex [Cp2NbH2(PbMe3)] (1). Compound 1 represents the first example of a stable complex with neighbouring hydride and terminal plumbyl substituents. The structure of this compound has been established by NMR and IR spectroscopy and confirmed by an X-ray structure analysis.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301112
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 80
    Electronic Resource
    Electronic Resource
    Chlorides and Acetylacetonates of Transition Metals as Catalysts for the Oxidation of 1-Indanol by Sodium Percarbonate (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1655-1658 
    Details
    ISSN: 0009-2940
    Keywords: Catalysis ; Oxidations ; Transition metals ; Sodium percarbonate ; 1, 2-Dichloroethane ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The screening of metal chlorides and metal acetylacetonates as catalysts for the oxidation of 1-indanol by sodium percarbonate (at reflux in 1,2-dichloroethane in the presence of small amounts of Adogen 464) has been carried out. The efficiency of the process depended on the nature of the transition metal and its oxidation state but, except for iron, was not greatly influenced by the nature of the ligands. Good conversions and yields have been obtained using PdCl2, RhCl3, RuCl3 and, particularly, MoO2(acac)2 as catalysts.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301116
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 81
    Electronic Resource
    Electronic Resource
    Contribution to the Chemistry of Boron, 240 . Studies on Benzo-1,3,2-diphosphaborolanes, Benzo-1,4,2,3-diphosphadiborinanes and Benzo-1,5,2,3,4-diphosphatriborepanesDedicated to my friend Prof. Dr. A. Meller on the occasion of his 65th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1677-1692 
    Details
    ISSN: 0009-2940
    Keywords: Benzo-1,3,2-diphosphaborolanes ; Benzo-1,3,2-diphosphaborolane dimmers ; Benzo-1,4,2,3-diphosphadiborinanes ; Rearrangement reaction ; Pentacarbonyl chromium complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of benzo- 1,3,3-diphosphaborolanes C6H4(PR)2BR' (R = H, iPr, SiMe3; R' = R2N, R) has been prepared by several routes and characterized by spectroscopic and - in part - by X-ray diffraction methods. They feature pyramidal P atoms with the substituents in antiperiplanar positions. The P atoms act as coordination sites for the (CO)5Cr fragment. In contrast to the R2N-bearing benzo-1,3,2-diphosphaborolanes, the derivative C6H4(PH)2BCMe3 (4f) dimerizes by additional B-P bond formation to produce a pentacyclic system (4f)2. - The reaction of C6H4(PHNa)2 with B2(NMe2)2Cl2 in THF/hexane yields the acyclic phosphanylborane Me2NB(PH-C6H4PH2)2 (15). However, if C6H4[P(iPr)Li]2 is allowed to react with B2(NMe2)2Cl2, the benzo-1,4,2,3-diphosphadiborinane 13 is obtained, together with its rearrangement product 2-bis(dimethylamino)borylbenzo-1,3,2-diphosphaborolane 14 which dimerizes to (14)2.  -  In contrast, the almost planar ring of the 2,3-dimesitylbenzo-1,4,2,3-diphosphadiborinane (16) possesses P and B atoms with a planar geometry. Short B-B and B-P bonds suggest that this new heterocycle can be regarded as a 6π electron system. Moreover, the benzo-1,5,2,3,4-diphosphatriborepane 18 forms readily forms readily from C6H4(PHNa)2 and Br(Me2N)B-B(N-Me2)-B(NMe2) Br to give a tub-shaped seven-membered C2B3P2 ring system with the P atoms in a pyramidal and the B atoms in a planar environment.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301120
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 82
    Electronic Resource
    Electronic Resource
    Geminal di(hypersilyl) Compounds  -  the Synthesis and Structure of Bis[tris(trimethylsilyl)silyl]methanol (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1709-1714 
    Details
    ISSN: 0009-2940
    Keywords: Silicon ; Strained molecules ; Silanes, sterically congested ; Tris(trimethylsilyl) silanes ; Silenes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tris(trimethylsilyl)silyllithium (1) reacts with methyl formate in diethyl ether (molar ratio 2:1) to give 1,2-di(hypersilyl)- ethylene 13. The formation of 13 proceeds through the intermediates formyl tris(trimethylsilyl)silane (4) and lithium bis-[tris(trimethylsilyl)silyl]methoxide (5). In diethyl ether, the alkoxide 5 spontaneously eliminates lithium trimethylsilanolate thereby generating 1,1-bis(trimethylsilyl)-2-[tris(trimethylsilyl)silyl]silene (9), which undergoes a formal [2+2] cycloaddition with the carbonyl compound 4 to afford 13. This was verified by crossover experiments. In Pentane, the alkoxide 5 is moderately stable. Thus, the intermediate 5, prepared by reaction fo 1 with tert-butyl formate in pentane. was protonated with water to give the di(hypersilyl)methanol 6 in good yield. The structure of 6 in good yield. The structure of 6 was elucidated by an X-ray crystal structure analysis, which expectedly revealed tremendous distortions of the molecular skeleton. Thus, the spatial demand of the two extended hemispherical (Me3Si)3Si groups forces a widening of the Si-C-Si angle at the central sp3 carbon atom to a value of 135.5°.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301123
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 83
    Electronic Resource
    Electronic Resource
    Compounds of Germanium and Tin, 22 - Reactions of a Silyene with a Germylene and a Stannylene: Formation of a Digermene with an Unusual Arrangement of the Substituents and of a Stannane (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1733-1737 
    Details
    ISSN: 0009-2940
    Keywords: Silicon ; Germanium ; Tin ; Carbene homologues ; Digermene ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of the diaminosilylene :Si(tBuNCH2CH2NtBu) (5) with the diaminogermylene :Ge(tBuNCH2CH2NtBu) is thought to proceed via a germasilene → silylgermylene rearrangement and dimerisation to furnish the (Z)-1,2-diamino-1,2-disilyldigermene (Z)-9. The X-ray structure analysis of (Z)-9 reveals a long Ge—Ge bond length of 245 pm and a large trans-bent angle of 42°. Air-oxidation of (Z)-9 takes place with retention of configuration at the germanium atoms to provide the corresponding substituted (Z)-2,4-digerma-1,3-dioxetane (Z)-10. Treatment of 5 with the stannylene :Sn[N(SiMe3)2)2 gives, as a final product, the hydridodisilylstannane 12. The structures of (Z)-10 and 12 were also determined by X-ray crystallography.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301205
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 84
    Electronic Resource
    Electronic Resource
    A Novel Approach to the Synthesis of Endohedral Fullerenes as Demonstrated by Endohedral Barium Fullerenes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1761-1764 
    Details
    ISSN: 0009-2940
    Keywords: Endohedral ; Barium ; Fullerenes ; Dibarium fullerenes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new route to endohedral fullerenes involving the evaporation of carbon and a metal at different positions, i.e. at different temperatures, in a radio-frequency furnace is described. For the first time, endohedral barium fullerenes within the composition range Ba@C74 to Ba@C136 have been produced in high yields as compared to hollow fullerenes, and have been extracted with CS2. Ba@C60, and Ba@C70, are only soluble in CS2 following sublimation. Furthermore, the first nonlanthanoid dimetallo fullerenes ranging in composition from Ba2@C88 to Ba2@C116 have been obtained. All endohedral barium fullerenes were characterized by mass spectrometry. Properties such as sublimation behaviour, solubility, and sensitivity to air have been studied.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301209
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 85
    Electronic Resource
    Electronic Resource
    N′,N′,N″,N″-Tetramethylguanidine-Substituted Phosphoryl Compounds as Ligands in Transition Metal Chemistry - Unusual Modes of CoordinationDedicated to Professor Roald Hoffmann on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1825-1832 
    Details
    ISSN: 0009-2940
    Keywords: N′, N′, N″, N′-Tetramethylguanidine ; Phosphoryl ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Methyl- and tert-butylphosphonic bis(N′,N′,N″,N″-tetramethylguanidinide) 1 and 2 were allowed to react with various transition metal compounds. The resulting complexes were studied by IR spectroscopy, mass spectrometry and, in the case of 10, by NMR spectroscopy. In the case of the compounds 7-10 the metal was coordinated only via the imino nitrogen atoms of 2, (IR evidence). X-ray structure analyses were performed for [L1CoBr2]2 6, L2CuCl2 9, and L2PdCl2 10 (L1 = 1, L2 = 2). In 5 L1 acts as an N,O bridging ligand, leading to tetrahedral coordination at Co and eightmembered (-Co-O-P-N-)2 rings. In 6 coordination by L2 chelates the metal atom through two N atoms, leading to PN2M rings; the coordination geometry is distorted planar.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301219
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 86
    Electronic Resource
    Electronic Resource
    Synthesis of Functionalized Carbamates through a Palladium-Catalyzed Reductive Carbonylation of Substituted Nitrobenzenes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 13-22 
    Details
    ISSN: 0009-2940
    Keywords: Carbamates ; Catalysis ; Substituted nitrobenzenes ; Palladium ; Reductive carbonylation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The palladium-catalyzed reductive carbonylation of ortho and para-substituted nitrobenzenes has proven to be an attractive route for the synthesis of functionalized carbamates. For the Pd(1, 10-phenanthroline)2(triflate)2 catalyst system, the scope of the reaction has been studied. Substrates with electron-donating substituents at the para position were found to decrease the catalytic activity, most probably as a result of their relatively low oxidizing capacity. the selectivity towards the desired carbamate, however, was increased for these substrates. Under the influence of electron-withdrawing substituents the azoxybenzene and azobenzene derivatives became important side products. Introduction of large steric hindrance at the ortho position of the nitro substrates gave rise to an interesting side reaction, viz. methoxylation of the aromatic ring. The methoxylation reaction appeared to occur on an intermediate species in the catalytic cycle. Several functionalities have shown to be resistant to the reaction conditions required for the conversion ot the nitro group. Especially with 4-nitrobenzoic acid, an extremely high activity and selectivity was found, thus yielding a very convenient synthesis for N-protected amines containing carboxylic acid function.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300104
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 87
    Electronic Resource
    Electronic Resource
    Dimeric Silver(I) Complexes of Some Isothiazole-Based LigandsDedicated to Prof. Dr. Rolf Gleiter on the occasion of this 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 95-100 
    Details
    ISSN: 0009-2940
    Keywords: Isothiazole complexes ; Dinuclear silver(I) complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of isothiazole-based potential ligands bearing substituents with additional donor sites in the 5-position of the heterocycle was synthesized [3-Me-5-R-C3HNS; R = CH=N(CH2)2py (1), CH=NCH2py (2), CH2N(CH2CH2NEt2)2 (4), (CH2)2SMe (5)]. Upon reaction with AgO3SCF3 they formed complexes [(1)AgOSO2CF3]2 (6), [(2)AgOSO2CF3]2 (7), [(4)Ag]2+2(O3SCF-3)2 (8) and [(5)AgOSO2CF3]2 (9), respectively. 6, 8 and 9 were shown by X-ray structural analyses to consist of dimeric units L2Ag2+2, either discrete (8), coordinated by terminal CF3SO-3 units (6). In 8 and 9 the isothiazole moiety is bonded to the metal center via the ring-N. The coordination potential of the isothiazole heterocycle is discussed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300115
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 88
    Electronic Resource
    Electronic Resource
    Synthesis and Structure of Binuclear Single-Bridged Bis[(phosphane)gold(I)]halogenonium Complexes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 115-118 
    Details
    ISSN: 0009-2940
    Keywords: Gold complexes ; Bromonium complex ; Halogenonium complex ; Halogen, two-coordinate ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions of (R3P)AuX (X = Cl, Br, I) with [(R3P)Au]+ BF-4 obtained from (R3P)AuCl and AgBF4 in tetrahydrofuran, lead to cationic binuclear gold(I) complexes of the general formula ([(R3P)Au]2X}+ BF-4. A number of chloro- (R = Ph, o-Tol, Mes, Bzl, Et), bromo- (R = Ph, o-Tol, Mes) and iodo-bridged (R = Ph, Mes) complexes of this type have been isolated and identified on the basis of their analytical and spectroscopic data. The crystal structure of bis[(triphenylphosphane)gold(I)]bromonium tetrafluoroborate was determined by single-crystal X-ray diffraction. The cations contain two-coordinate bromine atoms with an Au-Br-Au angle of 96.83(3)°.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300119
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 89
    Electronic Resource
    Electronic Resource
    A Specific Route to Enantiomerically Pure Asymmetric (η6-Arene)(η4-1,5-cyclooctadiene)Ru(0) ComplexesDedicated to Professor Rolf Gleiter on the occassion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 123-130 
    Details
    ISSN: 0009-2940
    Keywords: Arene complexes ; Ruthenium compounds ; Electrophilic substitution ; Lithiation ; Catalysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chiral or achiral (arene)(COD)Ru complexes can be made by replacing the η6-ligands of (η4-1,5-COD)(η6-1,3,5-cyclooctatriene)Ru (1) or (η4-1,5-COD)(η6-naphthalene)Ru (2) by a suitable arene. This well known reaction has been extended to mono- and dibromoarenes and we report a novel route to substituted (arene)(COD)Ru species, utilizing (bromoarene)-(COD)Ru as starting materials. These facilitate a rapid bromine-lithium exchange reaction with nBuLi at low temperatures and the lithiated species react readily with alkyl chloroformates as electrophiles. By using chiral electrophiles [alkyl = (-)-menthyl] enantiomerically pure or diastereomeric complexes containing CO2R* groups are formed, depending on the symmetry of the original complex. A diastereomeric 1:1 mixture was separated by recrystallization. All (arene)-(COD)Ru complexes tested so far are useful as catalysts for the hydrogenation of simple alkenes at room temperature.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300121
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 90
    Electronic Resource
    Electronic Resource
    Recent Advances in C-F Bond Activation (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 145-154 
    Details
    ISSN: 0009-2940
    Keywords: Fluorocarbons ; C-F bond activation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The main reaction pathways which lead to the breaking of C-F bonds in perfluoroalkanes and -arenes are discussed. Emphasis is placed on recent developments and on the mechanistic patterns that emerge.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300203
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 91
    Electronic Resource
    Electronic Resource
    Metal Atoms in the Synthesis of Metal Clusters, VIII.On the Reaction of Sterically Demanding Cyclopentadiene Ligands with Cobalt Atoms: Synthesis, Crystal Structure, Spectroscopic Behavior, and Reactivity of Di-, Tri- and Tetranuclear Hydrido Clusters of CobaltDedicated to Professor IV Siehert on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 161-170 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The metal-vapor reactions of Co atoms with 1,3-tBu2CpH (1a), 1,3-tBu2CpH (1a), 1,2,4-tBu3CpH (1b) and EtMe4CpH (1c) are described. With 1a the two mononuclear complexes [(η5-tBu2Cp) (η4-tBu2-1,3-cyclopentadiene)Co] (2a) and [(η5-tBu2Cp)2Co] (3a) were isolated, together with the dinuclear cobalt cluster [{(η5-tBu2Cp)Co}2H3] (4a) and trace amounts of the tetranuclear cluster [{(η5-tBu2Cp)CoH}4] (5a). The molecular structures of 3a and 4a were determined by X-ray diffraction. Reaction of 1b with Co atoms afforded a single product, the dinuclear cluster [{(η5-tBu3Cp)Co}2H3] (4b), whose molecular structure was determined by single-crystal X-ray diffraction. Both, 4a and 4b exhibit extremely short Co-Co distances [2.244(1) (4a) and 2.242(1) Å (4b)], as found for the Me5Cp analog [{(η5-Me5Cp)Co}2H3] (4c). Reaction of an isomeric mixture of Me4EtCpH (1c) with Co atoms furnished the mononuclear sandwich [ (η5-Me4EtCp)(η4-Me4Et-1,3- cyclopentadiene)Co] (2b), the trinuclear hydridocobalt cluster [{(η5-Me4EtCp)Co}3H4] (6a) and the tetranuclear hydridocobalt cluster [{(η5-Me4EtCp)Co}4H4] (5c). The molecular structure of 5c was determined by X-ray crystallography and revealed a tetrahedral arrangement of the cobalt atoms. The electrochemical behavior of the dinuclear complexes 4a-4c was studied by cyclic voltammetry. Reversible redox couples were found for all three compounds, with a correlation between the degree of alkyl substitution and their respective cathodic shifts. Compounds 4a and 4b react with CO to yield the mononuclear and dinuclear complexes [ (η5- CpR)Co(CO)2] (R=1,3-tBu2, 1,2,4-tBu3) (7a and 7b) as well as [{(η5-CpR)CO}2(CO)2] (8a and 8b). Reaction of the trinuclear hydridocobalt cluster 6a and its Me5Cp analog 6b with AgBF4 in the presence of PEt3 yielded the heteronuclear clusters [{η5-Me4CPR)Co}3AgP(Et)3H4]+[BF4]- (R=Et, Me) (9a and 9b). 9a was structurally characterized by X-ray crystallography.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300205
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 92
    Electronic Resource
    Electronic Resource
    Linked Benzylamido-Cyclopentadienyl Ligands: Synthesis and Characterization of Alkyl Titanium Complexes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 209-215 
    Details
    ISSN: 0009-2940
    Keywords: Titanium ; Amidocyclopentadienyl ligand ; Alkyltitanium compounds ; Lewis acids ; Agostic interactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Titanium complexes of the general type Ti(η5:η1-C5H4Si-Me2NCH2C6H3X2-2,5)Cl2 (X=H, F), containing a linked benzylamido-cyclopentadienyl ligand, were prepared by reaction of Ti(η5-C5H4SiMe2Cl)Cl3 with lithium amide Li(NHCH2C6H3X2-2,5). A single-crystal X-ray structural analysis of Ti(η5: η1-C5H4SiME2NCH2C6H3F2-2,5)Cl2 revealed a conformation in the solid state in which the aryl ring is turned away from the metal center. Ti(η5:η1-C5H4SiMe2NCH2C6H5)Cl2 can be alkylated with a variety of reagents to form extremely sensitive complexes of the type Ti(η5-C5H4SiMe,2NCH2C6H5)R2 (R=Me, CH2 C6H5, CH2SiME3, CH2CMe2C6H5). Reaction of Li2[C5Me4SiMe2NCH2C6H5] with TiCl3(THF)3 gave Ti(η5: η1-C5Me4SiMe2NCH2C6H5)Cl2, which can also be alkylated to form dialkyl complexes of the type Ti(η5:η1-C5Me4SiMe2NCH2C6H5)R2(R=Me, CH2C6H5, CH2SiMe3, C6H5).A single-crystal X-ray structural analysis of Ti(η5:η1-C5Me4SiMe2NCH2C6H5)(CH2C6H5)2 suggests the presence of α-agostic bonding of one of the titanium-bound CH2C6H5 groups to the titanium center.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300211
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 93
    Electronic Resource
    Electronic Resource
    Concave Reagents,22. Cyclopropanation of Alkenes with Ethyl Diazoacetate: Copper(I) Complexes of Concave 1,10-Phenanthrolines as Diastereoselective Catalysts (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 231-234 
    Details
    ISSN: 0009-2940
    Keywords: Diasteroselective cyclopropanation ; Copper compounds ; Homogeneous catalysis ; Molecular recognition ; Bimacrocycles ; Alkenes ; Macrocyclic ligands ; Heterocycles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Concave 1,10-phenanthrolines 1a-c have been used as ligands in the copper(I)-catalyzed cyclopropanation of alkenes 2 with ethyl diazoacetate. The complexes proved to be efficient cyclopropanation catalysts and exhibited an enhanced diastereoselectivity, particularly in the reactions of cyclic alkenes 2b-d. The preferred formation of exo-cyclopropanes 3b-d can be explained by the concave shape of these catalysts.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300215
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 94
    Electronic Resource
    Electronic Resource
    Synthesis of Polycyclic Hydrocarbons by Palladium-Catalyzed Cross-Coupling Reactions of Vinylic Bromides with Diphenylacetylene (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 261-265 
    Details
    ISSN: 0009-2940
    Keywords: Polycycles ; Hydrocarbons ; Palladium catalysis ; Domino processes ; Cross coupling ; Homogeneous catalysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Vinylic bromides of type 1 undergo cross-coupling reactions with diphenylacetylene (5) leading to various polycyclic hydrocarbons. The ratio of the 1:1 to the 1:2 products can readily be controlled by varying the reaction conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300220
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 95
    Electronic Resource
    Electronic Resource
    Silver Chloroacetate: Crystal Structure and Thermal Polymerization Mechanism (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 291-294 
    Details
    ISSN: 0009-2940
    Keywords: Halogenoacetates ; Silver salts ; Solid-state reactions ; Polymerization ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The structure of silver chloroacetate was determined by single-crystal X-ray structure analysis. This represents the first salt of a monohalogenoacetic acid with a monovalent metal whose structure was determined with high precision. The salt undergoes a thermally induced solid-state polymerization to polyglycolide under elimination of silver chloride. A probable mechanism for a structure-determined reaction in the solid state is discussed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300224
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 96
    Electronic Resource
    Electronic Resource
    Preparation of Methyl 2-[Bis(trimethylsiloxy)phosphoryl]-3,3,3-trifluoro-2- (trimethylsiloxy)propionate and Some Derivatives-Molecular Structure of Methyl 2-[Bis(trimethylsiloxy)phosphoryl]-3,3,3-trifluoro-2-hydroxypropionate (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 279-281 
    Details
    ISSN: 0009-2940
    Keywords: Methyl trifluoropyruvate ; Tris(trimethylsilyl) phosphite ; Methyl 2-[bis(trimethylsiloxy)phosphoryl]-3,3,3- trifluoro-2-(trimethylsiloxy)propionate ; Bis(trimethylsilyl) [(2,2-difluoro-l-trimethylsiloxy)ethenyl]- phosphonate ; Solid-state structures ; Fluorine ; Phosphorus ; Silicon ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Methyl trifluoropyruvate (1) and tris(trimethylsilyl) phosphite (3) reacted to give methyl 2-[bis(trimethylsiloxy)phosphoryl]- 3,3,3-trifluoro-2-(trimethylsiloxy) propionate (4). Partial hydrolysis furnished propionate 6, the molecular structure of which was obtained in the solid state. Attempted trimethylsilylation of the methylcarboxylato group in 4 using iodotrimethylsilane caused the formation of bis(trimethylsily1) [(2,2- difluoro- 1 -trimethylsiloxy)ethenyl]phosphonate (8). For comparison, methyl pyruvate (2) and 3 gave methyl 2-[bis(trimethylsiloxy)phosphoryl]-2-(trimethylsiloxy)propionate (5).
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300222
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 97
    Electronic Resource
    Electronic Resource
    Generation and Synthetic Application of Metallated Methyl Isopropenyl Ether, A Substitute for Acetone Enolate (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 45-48 
    Details
    ISSN: 0009-2940
    Keywords: Metallated methyl isopropenyl ether ; Tetrahydrofurans ; 1-Oxabicyclo[4.3.0]heptanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Methyl isopropenyl ether (1) has been metallated at low temperature with a 1:1 molar mixture of n-BuLi/t-BuOK in THF-hexane, and subsequently functionalized with a variety of electrophilic reagents. At temperatures higher than - 30°C, the metallated methyl isopropenyl ether (2) decomposes with formation of allene. When the suspension of 2 is allowed to warm up to room temperature in the presence of an additional equivalent of n-BuLi, the intermediary allene is converted into 1-propynyllithium (2c), which reacts with propylthiocyanate to give 1-propylthio-1-propyne (4). Some of the functionalization products were subjected to acidic hydrolysis affording the expected methyl ketones.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300107
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 98
    Electronic Resource
    Electronic Resource
    (EIZ)-Equilibria, 19 Part 18: Ref.[19].  -  [*I X-ray structural analyses. Dimeric α-Lithio-2,6-dimethylstyreneDedicated to Prof. Joseph Klein on the occasion of his 80th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 585-592 
    Details
    ISSN: 0009-2940
    Keywords: Aggregations ; Complex, tert-butyl methyl ether ; diastereotopomerization, (EIZ) ; NMR, coupling, constants, HH, CH, CLi ; NMR, Lithiation shifts ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Improved preparations of 2,6-dimethylstyrene (5) and its α-bromo derivative (10) are described. The Br/Li exchange reaction of 10 provides single crystals of the title compounds 11 or 12, which were characterized as disolvated dimers by X-ray analyses. A similar dimer persists in diethyl ether, tert-butyl methyl ether, and toluene at all accessible temperatures, with significant lithiation NMR shifts (relative to 5) partially due to charge delocalization from the sp2-carbanionic center. Some NMR coupling constants are typical of the dimeric aggregate. The configurational (E,Z) lability is quantified in toluene solution.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300509
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 99
    Electronic Resource
    Electronic Resource
    Dinuclear Cobalt(II) Complexes of Pyrazole Ligands with Chelating Side ArmsDedicated to Prof. Dr. Walter Siebert on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 605-613 
    Details
    ISSN: 0009-2940
    Keywords: Pyrazolate complexes ; Dinuclear complexes ; Bridging ligands ; Cobalt ; Conformational analysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of pyrazole-based potential ligands bearing polydentate amine substituents in the 3- and 5-positions of the heterocycle has been synthesized [3,5-bis(R2NCH2)-pyzH R2N = Me2N(CH2)3NMe (2aH), [Me2N(CH2)3]2N (2bH), (Et2NCH2CH2)2N (2cH)]. Upon reaction with two equivalents of CoCl2 they form complexes LCo2Cl3 (3a-c; L = 2a-c, respectively) which are shown crystallographically to contain a dinuclear metal core bridged by both the pyrazolate unit and a chlorine atom, with each cobalt center carrying a further terminal chlorine atom. Two of the ligand side arms in 3b, c are dangling, thus leading to five-coordination of the cobalt(II) centers in all cases. Addition of two equivalents of NaBPh4 to solutions of 3b, c induced coordination of the formerly dangling side arms to the metal centers by substitution of the terminal chlorine atoms. The resulting compounds [LCo2Cl](BPh4)2 (4b, c, respectively) were characterized by X-ray structure analyses. They can be viewed as dinuclear linked versions of tran-type complexes [(tran = tris(aminoalkyl)amine] with distorted trigonal-bipyramidal coordination spheres around cobalt(II). Conformational analyses employing force-field calculations were carried out for 4b, c in order to rationalize the conformations observed in the solid state with regard to the accessible conformational space.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300511
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 100
    Electronic Resource
    Electronic Resource
    Gold Coordination by 2-(Diphenylphosphanyl)aniline (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 647-650 
    Details
    ISSN: 0009-2940
    Keywords: Gold(I) coordination ; 2-(Diphenylphosphanyl)aniline ; Ambidentate P ; N ligands ; P Ligands ; Ligand effects ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of 2-(diphenylphosphanyl)aniline (1) with (tetrahydrothiophene)gold(I) chloride in the molar ratio 1:1 gives a stable molecular complex 2, in which the gold atom is bonded to the phosphorus atom. Reaction of two equivalents of ligand 1 with one equivalent of the salt [(tht)2Au]ClO4 results in the displacement of both thioether ligands, affording the ionic complex {[(2-NH2C6H4)PPh2]2Au}+ ClO-4 (3a), in which the metal center is exclusively P-coordinated. Treatment of [(tht)2Au]ClO4 with ligand 1 (1:1) affords the mixed P/S-coordinated complex 4, the structure of which has been confirmed by single-crystal X-ray diffraction. The reaction of ligand 1 with [(Ph3P)Au]+ BF-4 leads to a mixture of products which are components of an equilibrium between the unsymmetrical salt {[(2-NH2C6H4)PPh2]Au(PPh3)} BF-4 with the two symmetrical species 3b (the BF-4 analogue of 3a) and [(Ph3P)2Au]+ BF-4, With {[(Ph3P)Au]3O}+ BF-4 as the aurating agent, the ligand 1 (molar ratio 1:1) is converted into a polynuclear complex 7, which is tentatively assigned a structure with intimate aggregation of six gold atoms.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300516
    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...