Library

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
Filter
  • Articles: DFG German National Licenses  (2,074)
  • 2005-2009
  • 2000-2004
  • 1990-1994  (693)
  • 1985-1989  (658)
  • 1975-1979  (723)
  • 1940-1944
  • 1990  (693)
  • 1987  (658)
  • 1975  (723)
  • Inorganic Chemistry  (2,074)
Source
  • Articles: DFG German National Licenses  (2,074)
Material
Years
  • 2005-2009
  • 2000-2004
  • 1990-1994  (693)
  • 1985-1989  (658)
  • 1975-1979  (723)
  • +
Year
  • 201
    ISSN: 0009-2940
    Keywords: Chlorosilanes, hexacoordinated ; Silicon complexes, octahedral ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Contributions to the Chemistry of Halogenosilane Adducts, 21.  -  Preparation, Properties, Crystal and Molecular Structure of Dichloro(1,10-phenanthroline)bis(trichlorosilyl)silicon, (SiCl3)2SiCl2 · phenSi3Cl8 · phen (1) is obtained as a stable solid by the reaction of Si3Cl8 with phen. The structure of 1 in solution and its reactions correspond to that of Si3Cl8 · bipy reported earlier (1H-NMR and IR studies). Rearrangement of 1 occurs in solution to give bis(silyl)-substituted 1,2-dihydrophenanthroline. From THF/C6H6 solution crystalline Si3Cl8 · phen · C6H6 (1a) is obtained. The X-ray structure determination shows 1a to be monoclinic, space group P21/n (Z = 4). Phenanthroline is coordinated to the central silicon atom of the trisilane with its plane normal to the linear Si3 chain having two tetrahedral terminal SiCl3 groups. The coordination octahedron is regular.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 202
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 2311-2315 
    ISSN: 0009-2940
    Keywords: Molybdenum complexes ; Cyclopentadienyl, tri-, tetra-, and pentaalkylated ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Molybdenum Complexes with Highly Alkylated Cyclopentadienyl LigandsReaction of hexacarbonylmolybdenum with 1,2,3,4-tetraisopropylcyclopentadiene gives [(η5-C5iPr4H)Mo(CO)3H] (1), which on treatment with 2,5-norbornadiene is dehydrogenated to [{(η5-C5iPr4H)Mo(CO)2}2](Mo ≡ Mo) (2). The mixed-substituted dimolybdenum complex [(η5-C5Me5)(CO)2Mo ≡ Mo(CO)2(η5-C5iPr4H)] (6) is accessible, e.g., from [(η5-C5Me5)Mo(CO)3Cl] and [(η5-C5iPr4H)Mo(CO)3]Na (3). Complex 3 yields [(η5-C5iPr4H)Mo(CO)3Cl] (4) with CuCl2 and [(η5-C5iPr4H)Mo(CO)3-SiHMe2] (5) with Me2HSiCl. Low-temperature 1H-NMR spectra of [(η5-C5iPr5)Mo(CO)3CH3] (7), synthesized from [(η5-C5iPr5)Mo(CO)3]Na and MeI, show the signals of two isomers with different orientation of the isopropyl groups about the five-membered ring. ΔG
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 203
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 2325-2327 
    ISSN: 0009-2940
    Keywords: Diselenide, torsion angle/NMR, 77Se/Selenenyl halide ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bis[tris(trimethylsilyl)methyl] Diselenide: An Unusual Diselenide with Sterically Enforced trans-C2h ConformationDeselenation of bis[tris(trimethylsilyl)methyl] triselenide (1) with copper occurs with formation of bis[tris(trimethylsilyl)-methyl] diselenide (2) and minor amounts of 3,3,5,5-tetrakis(trimethylsilyl)-1,2,4-triselenolane (3). The structures of 2 and 3 have been studied by multinuclear NMR spectroscopy and by X-ray crystallography. The C—Se—Se—C moiety of 2 adopts an unusual antiperiplanar conformation. Cleavage of the Se — Se bond by iodine providing iodo[tris(trimethylsilyl)-methyl]selane (5) is complete with 2, but reversible with 1.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 204
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 2373-2380 
    ISSN: 0009-2940
    Keywords: Hydride abstraction ; Aromatisation ; Phenylallyl cations ; Isotope effects ; Tunneling ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Free 1-Phenylallyl Cations in the Aromatisation of Dihydronaphthalenes by Triphenylmethyl TetrafluoroborateThe aromatisation of 1,2- and 1,4-dihydronaphthalenes by trityl cations proceeds by a common intermediate, the 1-phenylallyl cation 4 of sufficient lifetime to allow for both side reactions and loss of stereoselectivity. The primary hydride abstraction occurs with moderate tunneling participation and in a linear geometry of the three participating atoms as shown by the temperature dependence of the primary isotope effect.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 205
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 2395-2401 
    ISSN: 0009-2940
    Keywords: Allylboration reaction ; Asymmetric induction ; Calculations, force-field ; Transition-state models ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The direction (Cram/anti-Cram) and the extent of asymmetric induction on addition of crotylboronates to a range of chiral aldehydes was investigated. A reversal in the sense of the asymmetric induction on changing from the Z- to the E-crotylboronate was found for aldehydes having polar α substituents and for some of the nonpolar chiral aldehydes. Forcefield calculations on transition-state models reproduced these results in the majority of the cases investigated despite of unaccounted short comings of the method.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 206
    ISSN: 0009-2940
    Keywords: Methyl lithium (deuterated)/Neutron diffraction ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metal Alkyl und Aryl Compounds, 40% - Structure Refinement of Methyl Lithium by Neutron Diffraction of (LiCD3)4 at 1.5 and 290 KThe structure of deuterated methyl lithium has been refined by neutron powder diffraction at 1.5 and 290 K. At both temperatures a cubic body-centered arrangement of (LiCD3)4 units (Td, symmetry) is found. In agreement with previous X-ray powder investigations (290 K) each tetramer contains a distorted cubic Li4C4 core with pyramidal methyl groups in staggered positions with respect to the adjacent Li3 unit. Refined values, in particular precise D positions, have now been obtained.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 207
    ISSN: 0009-2940
    Keywords: Nitroxides, dimerization of / Vinyl nitroxides / 1,2-Oxazepines, 2,5,6,7-tetrahydro- / Nitrones ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Nitroxides (Aminyl Oxides), 43. - The Effect of Structural Features upon the Dimerization of Vinyl Nitroxides Substituted in β-Position by Cyclic Acyl GroupsReaction between N-alkyl- and N-arylhydroxylamines and hydroxymethylene compounds 4 (derivatives of menthone, norboranone, borananone, indanone, and γ-butyrolactone) affords nitrones existing in the tautomeric forms 5 and 6. Oxidation of these nitrones generates the β-acylated vinyl nitroxides 7, which dimerize in various ways. The N-alkyl-substituted vinyl nitroxides 7DA, De, Ea, Ga, and Gf yield simple CC-bonded dimers 8 From 7Ba dimer 10 is formed via 8Ba. The structure of 10 is confirmed by an X-ray analysis. In contrast, the N-arylsubstituted vinyl nitroxides 7 Ab, Fc, and Bc as well as the N-alkyl-substituted 7 Aa afford the bicyclic dimers 9 which arise by OC dimerization followed by an intramolecular 1,3-dipolar cycloaddition. Finally, the vinyl nitroxides 7Dc and Dd underwent further oxidation to give dehydrodimers 12. 12e is formed only if 6De is oxidized by a large excess of lead dioxide.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 208
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 621-626 
    ISSN: 0009-2940
    Keywords: Key Words: Hydrogen transfer / Aromatization / Mangenese reagents / Isotope effects / Dehydrogenation, mechanism of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Hydrogen Transfer Reactions, 141) - The Dehydrogenation of 1,4-Dihydroarenes by Manganese OxidantsHydrogen abstraction from 1,4-dihydroarenes by both MnO2 and the KMnO4-dicyclohexano-[18]crown-6 complex occurs successively. In the first, rate-determining step one hydrogen is transferred. A synchronous transfer (by cyclic or termolecular pathways), a SET mechanism, or the addition of the permanganate ion to the double bond are not in accord with the large isotope effects. A moderate cis-selectivity is found for the abstraction of the second hydrogen by MnO2.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 209
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 643-645 
    ISSN: 0009-2940
    Keywords: Concave base / Macrocycle / 1,10-Phenanthroline / Cyclophane / Aryl lithium compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The addition of lithium aryls 3 to 1,10-phenanthroline (2), functionalization of the rearomatized bisadduct 8b to the tetraphenol 8d, and cyclization of 8d with two equivalents of an α,ω-ditosylate 9 led to a highly symmetrical, conformer-free bimacrocyclic 1,10-phenanthroline 10a in which the basic and coordinating region possesses a concave shielding.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 210
    ISSN: 0009-2940
    Keywords: σ,σ-Alkyne-bridged metal complexes / Carbonyl iron, ruthenium, manganese and rhenium compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Hydrocarbon-Bridged Complexes, XIIII). - Nucleophilic Attack of Carbonylmetallates on Cationic Alkyne Complexes [CpL2M(η2-RC I CR)]+(M = Fe, Ru): μ-η1 : η1-Alkyne-Bridged ComplexesThe σ,σ-alkyne-bridged complexes Cp(Me3P)2Ru[μ-η1:η1-(MeO2C)C = C(CO2Me)]MLn (1) [MLn = Ru(CO)2Cp, Mn(CO)5, Re(CO)5] are formed by addition of [Ru(Cp)(CO)2]-, [Mn-(CO)5]-, and [Re(CO)5]- to the alkyne ligand of [Cp-(Me3P)2Ru(MeO2CC≡CCO2Me)]+ and by addition of [Re-(CO)5]- to [Cp(OC)(Ph3P)Fe(MeC≡CMe)]+. The crystal structure of 1a was determined by X-ray diffraction and allows the comparison of bimetallic complexes with M-C≡C-M, M-C(R)=C(R)-M, and M - CH2CH2-M bridges. Addition of [Re(CO)5]- to [Cp(OC)(L)Fe(RC≡CR)]+ (L = CO:R = Me; L = P(OPh)3, PPh3; R = Et) yields the complexes Cp(OC)-(L)Fe-Re(CO)5 (3) with metal-metal bond.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 211
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 29-34 
    ISSN: 0009-2940
    Keywords: 1λ4,3λ4,5λ4,-Trithia-2,4,6,8,9-pentaazabicyclo [3.3.1]nona-1(9),2,3,5,7-pentaene, 7-trifluormethyl derivative, reactivity of / Coordination chemistry in liquid SO2 / Nickel(II) complexes with CF3CN5S3 / Sulfur dioxide, O-coordination to Ni(II) / Silver complexes with CF3 CN5S3 ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 7-(Trifluormethyl)-1λ4,3λ4,5λ4,-trithia-2,4,6,8,9-pentaazabicyclo[3.3.1]nona-1(9),2,3,5,7-pentaene as Ligand in Coordination ChemistryMany possibilities exist for the title compound CF3CN5S3 (3) (L) to coordinate to transition metal centers. From the reaction of 3 with [Ni(SO2)2](AsF6)2 and AgAsF6 in liquid SO2 [Ni-(SO2)2L2(FAsF5)2) (11) and [AgL]AsF6 (13) or [AgL2]AsF6 (14), respectively, were isolated. As shown by X-ray structure determination of 11 and 14, L coordinates as expected from MNDO calculations.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 212
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 53-61 
    ISSN: 0009-2940
    Keywords: Dioxazaphosphaborepine / Dioxaphospholanylaminoborane / Dioxarsolanylaminoborane / Dioxastibolanylaminoborane ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Contributions to the Chemistry of Boron, 198. - Reactions of Amino-imino-boranes with Dioxaphospholanes, Dioxarsolanes, and Dioxastibolanes(tert-Butylimino)(2,2,6,6-tetramethylpiperidino)borane (1) inserts into the exocyclic PX bond of 2-methoxy- and 2-(dimethylamino)-1,3,2-dioxaphospholanes, while ring expansions to the seven-membered dioxazaphosphaborepanes 4 and 5 are observed with fluoro-, chloro-, bromo-, and methyl-dioxaphospholanes and their benzo derivatives. These decompose at elevated temperatures producing the (tetramethylpiperidino)dioxaborolane 12 and benzodioxaborole 20, respectively, and diazadiphosphetidine derivatives. Insertion into the exocyclic bond occurs also between 1 and methoxy-benzodioxarsole (16) and -benzodioxastibole (17). The chloro derivatives, however, react with 1 to give 20 and (tBuN = ECl)2 (E = As, Sb) products. (2,6-Diisopropylphenylimino)(2,2,6,6-tetramethylpiperidino)borane (6) behaves similarly with the exception that 2-chloro-1,3,2-benzodioxaphosphole yields the exocyclic insertion product. It appears from these experiments that the insertion into the exocyclic bond of the heterocyclic compounds yields kinetically controlled products, while ring expansion followed by expulsion of a dioxaborolane is thermodynamically controlled.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 213
    ISSN: 0009-2940
    Keywords: Tandem mass spectometry / Bond activation, C-C and C-H / Isomerization, degenerate / Transition-metal ions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Extensive labeling studies permit to unravel the mechanisms by which bare Fe+ activates C-H and C-C bonds of n-heptyltrimethylsilane in the gas phase. While the neutral products C3H8, C5H12, Si(CH3)4, and Si(CH3)3C25 are due to an initial insertion of Fe+ into various C-C bonds of the n-heptyl chain, followed by β-hydrogen transfer and reductive elimination of the neutrals, molecular hydrogen and HSi(CH3)3 ar suggested to result from initial activation of specific C-H bonds. The formation of C2H4 is preceded by a skeletal rearrangement of the heptyl chain, rendering C-1/C-4 and C-2/C-3 equivalent; a metallacycle 10 is suggested as an intermediate.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 214
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 243-250 
    ISSN: 0009-2940
    Keywords: Cyanide complexes, organometallic, polynuclear / Redox chemistry / Ruthenium clusters ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Redox Chemistry, Dinuclear Complexes, and Ru3,-Cluster Derivatives of the “Ligand” [Cp(CO)2Mn - CN]-By means of the compounds Na[Cp(CO)2MnCN] (1a, b) the abilities of the cyanide ion to link different organometallic units and to stabilize unusual electron counts in organometallic complexes were tested. The dinuclear complexes [Cp(CO)2Mn-CN-M]- [form M = MnCp(CO)2 and W(CO)5 as PPN salts 2a, 3a] as well as Cp(CO)2Mn-Cn-M [for M = MoCp(CO)3 and NiCpPPh3, 4a, 5a] were obtained in a pure state. From the reactions with Ru3(CO)12 the cluster derivatives HRu3(CO)10[μ-NC-Mn(CO)2Cp] (6a, b) and Ru3(CO)10[μ-NC-Mn(CO)2Cp]2 (7b) were characterized. One-electron transfers were investigated for the starting complex and for the two anionic dinuclear complexes 2a, 3a. Crystal structures were determined of the dinuclear Mn-CN-Mn compex 2a and of the two cluster derivatives 2b, 7b.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 215
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 251-256 
    ISSN: 0009-2940
    Keywords: Arsonium salts, tri- and tetraferrio- / Arsane, tris(trimethylsilyl)- / Permetalated tetrahedral main group elements ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tris(trimethylsily1)arsane as a Starting Compound for Tri- and Tetraferrioarsonium Salts; Crystal Structure of [{Cp(CO)2Fe}3AsOH]B(C6H5)4Tris(trimethylsilyl)arsane (1) reacts with an excess of CpFe(O)2Cl (2) to give tetraferrioarsonium chloride [{Cp(CO)2Fe}4As]Clk (4a), which may be converted into the corresponding tetraphenylborate 4b by Na[B(6H5)4]. In the Presence of water one organometallic ligand is hydrolysed to yield the triferriohydroxyarsonium tetraphenylborate 5 which crystallizes in the triclinic space group P&1bar; and shows a trigonal pyramidal configuration at the arsenic atom.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 216
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 277-283 
    ISSN: 0009-2940
    Keywords: Catalysis / Kinetics / Carbon dioxide / Oxiranes / Carbonates ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bifunctional Catalysis of the Reaction of Carbon Dioxide with OxiranesKinetic investigation of the Lewis acid/Lewis base-catalyzed reaction of carbon dioxide with monosubstituted oxiranes 1 to cyclic carbonates 2 at atmospheric pressure reveals that the rate depends first order on substrates and the catalyst components ZnCl2 and (n-Bu)4NI. Electron-releasing substituents accelerate the reaction, except they are sterically demanding like the tert-butyl group in which case complete inhibition occus; 2,2-disubstituted oxiranes are inert. The activation parameters are ΔH≠ = (71.4 ± 3.7) kJ ± mol-1 und ΔS≠ = (-49.2 ± 9.3) J ± K-1. A rate law is established for the multi-step reaction mechanism and simplified for the extremes of high and low pressure of carbon dioxide. The reactivity pattern of several catalyst combinations suggests that solvated zinc chloride and trihalogenozincates are the Lewis acids which catalyze the nucleophilic ring opening of the oxirane by iodide to the corresponding iodo alcoholate. This is stabilized by the Lewis acid as indicated by the investigation of the stereochemistry at the unsubstituted ring carbon atom by the use of [2-D]-2-phenyloxirane. Nucleophilic attack of te alcoholate at carbon dioxide leads t the linear carbonate which is transformed into the product by intramolecular substitution of iodide.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 217
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 293-294 
    ISSN: 0009-2940
    Keywords: 1,2,3-Triborolane / Dicyclopentadiene / Dichloro(diisopropylamino)borane, dehalogenation product of / Triborane(5), 1,2,3-tris(diisopropylamino)- ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: (3α,4β,4aβ,7aβ,8β,8aα)-1,2,3-Tris(diisopropylamino)-1,2,3,3a,44a,5,7a,8,8a-decahydro-4,8-methanoindeno[5,6-d]-1,2,3-triborol (1) is formed from dicyclopentadiene and dichloro(diisopropylamino)borane upon treatment with sodium/potassium alloy in hexane. 1,2,3-Tris(diiso propylamino)triborane(5) (2) was also obtained. 1 is characterized by elemental analyses, spectroscopic data, and by an X-ray structure analysis, 2 by its MS and NMR data.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 218
    ISSN: 0009-2940
    Keywords: N-Benzylpyridinium bromide / MO calculations versus crystal structure determinations / Conformational analysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Conformational Analysis of N-Benzylpyridinium Bromide: A Comparison of Crystal Structure Data with Results of Semiempirical Calculations (MINDO/3, MNDO, AM 1, and PM3)The conformation of the title compound 1b is investigated by X-ray analysis and semiempirical MO methods (MINDO/3, MNDO, AM1, PM3). For the calculation of bond lengths and bond angles, AM1 and MINDO/3 are superior. Without complete calculation of the hypersurfaces of the variable D1, D2 and the relative energy (e. g. Figure 2), AM1 and MNDO can lead to false interpretations. Cuts through these surfaces (Figure 1) are calculated within moderate CPU time, Normally, these cuts are sufficient to characterize the conformational situation. The electronic influence of the phenyl group on the N1-C7 bond length of N-alkylpyridinium salts and on the dissociation energy ΔHz (eg. 2) is estimated. The comparison of the data of 1a and 1b reveals that this group causes an elongation of this bond by 2 pm and a decrease of the dissociation energy by 200 kJ/mol.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 219
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 471-475 
    ISSN: 0009-2940
    Keywords: Nickelapnicogencubanes / cyclo-P3 Sandwich ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: NickelapnicogencubanesThe thermolysis of [C*pNi(CO))]2 (1) (C*p=η5-C5Me5) and [Cp′Ni(CO)]2 (6) (Cp′ = η5-C5H4Me) with the pnicogens E4 (E = P, As) affords the distorted cubanes [(C*pNi)3(μ3-E)(E4)] (2a: E = P; 2b: E = As), the sandwich complex [C*pNi(η3-P3)] (3), as well as the cubanes [Cp′Ni(μ3-E)]4 (7a,b) and the trinuclear cluster [(Cp′Ni)3(μ3-CO)2] (8). With [M(CO)5(thf)], 2a and 3 give the multinuclear clusters [(C*pNi)3(μ3-P)(P4)M(CO)5] (4a: M = CR; 4b: M = Mo; 4c: M = W) as well as [C*pNi(P3)-{Cr(CO)5}3] (5). In addition to the NMR studies, 2a,b and 3 have been characterized by X-ray structure analyses.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 220
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 485-487 
    ISSN: 0009-2940
    Keywords: [2 + 2] Cycloaddition / Iminoborane / Carbene-metal complex / Azaboratantalacylobutane / Tantalum complex ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: [2 + 2] Cycloaddition of Iminoboranes to a Neopentylidenetantalum ComplexThe neopentylidene complex(η-Cp)cl2Ta=CHtBu (1) and the iminoboranes R′B≡NR (2a-d, R′/R = Et/tBu, Bu/tBu, iBu/ iBu, Ph/tBu) undergo a [2 + 2] cycloaddition yielding the corresponding 1-aza-2-bora-4-tantalacyclobutanes 3a-d. The crystal and molecular structure of 3c is reported.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 221
    ISSN: 0009-2940
    Keywords: 1,3,5,7-Cyclooctatetraene / 9-Borabicyclo[4.2.1]nona-2,4,7-triene, 9-(diisopropylamino)- / Borane, dihalogeno(diisopropylamino)- ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of 1,3,5,7-cyclooctatetraene with sodium-postassium alloy and dihalogeno(diisopropylamino)boranes in 1,2-dimethoxyethane gives the title compound, characterized by elemental analysis, MS (EI, FI), NMR (1H, 11B, 13C), and X-ray crystallography.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 222
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 481-484 
    ISSN: 0009-2940
    Keywords: Lanthanide chelates / Praseodymiumbis(triethanolamine) trication / Ytterbiumbis(triethanolamine) trication ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Structures of Bis(triethanolamine)lanthanide ComplexesThree novel lanthanide triethanolamine chelates {Ln[N(CH2-CH2OH)3]2}(CF3SO3)3 (Ln = Pr, 1; Yb, 2; Lu, 3) were synthesized from Ln(CF3SO3)3 and triethanolamine in THF. The structures of 1 and 2 were determined by single-crystal X-ray diffraction studies. The isostructural compounds crystallize with three molecules of THF and possess nonacoordinate lanthanide ions with a monocapped tetragonal antiprismatic coordination geometry.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 223
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 589-594 
    ISSN: 0009-2940
    Keywords: Sila-ethenes / Carbenes / Diazo compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: UV photolysis of diazo(disilanyl)methyl ketones 2 in benzene generates acyl(disilanyl)carbenes 3, which rearrange to 3-OxO-1-sila-1-propenes 4. The latter compounds are reactive intermediates which either cyclize to l-oxa-2-sila-3-cyclobutenes 5 or form the eight-membered cyclodimers 6, depending on the substituent of the acyl function. In a side reaction, isomerization of 4 to disilylketenes 7 takes place in some cases. On the other hand, photolysis of diazo ketone 13 yields both the l-oxa-2-sila-3-cyclobutene 5a (via the acylsilene 14) and the adamantyl (trisilanyl)ketene 15 (by Wolff rearrangement).
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 224
    ISSN: 0009-2940
    Keywords: 2-Azaalenyl chromium complexes, building blocks for cyclopropanes and 1,3-diaminoindenes / 1-Aminoalkynes, insertion into Cr = C, C = 0, and C - 0 bonds / Cyclopropanation, intramolecular, via iminocarbene chromium complexes / 1,3-Indanediones and γ-lactones via cyclic anhydrides ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organic Syntheses via Transition Metal Complexes, 43. - 2-Azaallenyl Chromium Complexes; Insertion of 1-Amino-propyne into M = C and C = 0 Bonds: Intramolecular Cyclopropanation and [3 + 21 Cycloaddition with Formation of a 1,3-DiaminoindeneOrganic Synthese via Transition Metal Complexes, 431). - 2-Azaallenyl Chromium Complexes; Insertion of 1-Aminopropyne into M = C and C = O Bonds; Intramolecular Cyclopropanation and [3+2]Cycloaddition with Formation of a 1,3-Diaminoindene The 2-azaallenyl complex LnM⊖ -C(Ph)=N⊕ = C(Ph)OCO-Ph 3 [LnM = Cr(CO)5] adds to the 1-aminopropyne Et2N-C = C-CH3 (4) to give the aminocarbene complexes LnM=C(NEt2)-C(CH3)=C(Ph)-N(COPh)2 [(E)-5] and LnM=C(NEt2)-C(CH3)=C(Ph)-NH(COPh) [(E)-9] (by insertion of 4 into the M = C bond of 3) as well as a 1,3-diaminoindene 6 (by [3+2] cycloaddition). An iminocarbene complex LnM = C(Ph) - N=C(Ph) -O-C(Ph) = C(CH3)-CONEt2 (7) is formed as a further product (by insertion of4 into the C=O bond of 3). The latter type of reaction can also be applied to metal-free carbonyl compounds: thus phthalic anhydride reacts smoothly with 4 to give a γ-lactone 12 and a 1,3-indanedione 13 by insertion of 4 into a C=O and C-O bond, respectively. The thermolysis of the iminocarbene complex 7 yields a cyclopropane derivative 14 by an intramolecular attack of the carbene carbon at the (O)C=C bond. The structure of 14 has been determined by a crystal structure analysis. On thermolysis of 3 a triphenyloxazole 15 is obtained. The mechanisms of these reactions are discussed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 225
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 757-760 
    ISSN: 0009-2940
    Keywords: Tetraphosphacubene, tetra-tert-butyl- / Tetraphosphatetrasilacubane, tetra-tert-butyl- / MO calculations / PE spectroscopy ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Strong P - P Interactions in Tetraphosphacubanes. A PE-Spectroscopic InvestigationThe comparison between the first peaks of the PE spectra of (tBuCP)4 (2a) yields about the same ionization energy for the first peak (4t2), but a large difference (ca, 0.8 eV) for the second peak (1t1). This difference is due to a strong interaction of the n orbitals at P with the P-C σ bonds in 1. This n/σ interaction is much smaller in the case of 2. The energy difference between 24T2 and 23A1, corresponding to the lone-pair combinations of the n orbitals at the P atoms, amounts to ≥ 3.4 eV for 1a and is estimated at ≥ 1.6 eV for 2a. The net charges for the P atoms in 1 are calculated to be positive, those for the C atoms negative. In the case of 2 negative values result for P and positive values for the net charges at Si.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 226
    ISSN: 0009-2940
    Keywords: Gold complex, dinuclear / Silyl complex / Gold - gold interaction ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Transition-Metal Silyl Complexes, 34. - A Dinuclear Gold Silyl Complex with Gold- Gold Interaction Between an (R3P)2Au and an (R′3,Si)ClAu UnitPh2MeP-Au-Cl reacts with Ph2MeP-Au-SiPh3 to form the dinuclear complex (Ph2MeP)2Au2(Cl)SiPh3, which is in equilibrium with its starting compounds. An X-ray structure analysis reveals that it consists of a (Ph2MeP)2Au and a (Ph3Si)ClAu unit, which are held together by Au-Au interaction [298.07(4) Pm]. The approximately linear AuL2 units are orthogonal to each other.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 227
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 800-800 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 228
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 707-712 
    ISSN: 0009-2940
    Keywords: Nitrogen base - organoboron adducts/Triselenadiborolanes/Fluctuation/Adducts of nitrogen bases with organoboron compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Stickstoffbase - Dialkyl-1,2,4,3,5-triselenadiborolane3,5-Dialkyl-1,2,4,3,5-triselenadiborolane RBSe3BR (1) [R = C2H5 (1a) und R = C3H7 (1b)] bilden bei Raumtemperatur mit überschüssigen N-Basen [Pyridin (P), 3,5-Dimethylpyridin (m2P), 3-Chlorpyridin (cP) und Chinuclidin (Q)] stabile 2:1-Additionsverbindungen [P2-1a,b, (m2P)2-1a, cP-1a, Q2-1a, b]. In Lösung existieren Gemische von (syn/anti)Q2-1a (1H-, 11B-NMR). (syn)Q2-1a steht bei -80°C mit Q-1a und Q im Gleichgewicht. Festes Q2-1a liegt als (anti) Q2-1a vor (Kristallstrukturanalyse). In Lösung bilden 1 bei Raumtemperatur mit äquimolaren Mengen an N-Basen die 1:1-Addukte [(N-Base)-1], in denen nur ein Bor-Atom vierfach koordiniert ist. 1: 1-Addukte mit fluktuierender N-Base zwischen den beiden Bor-Atomen werden bei Temperatursteigerung beobachtet (120°C: 11B-NMR). Hexamethylentetramin (Ur) bildet stabile, feste 1: 1- und 2: 1-Addukte (Ur-1a, Ur2-1a).
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 229
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 739-745 
    ISSN: 0009-2940
    Keywords: Phosphido complexes / Phosphavinylidene complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Transition-Metal-Substituted Acylphosphanes and Phosphaalkenes. XIV. - Transition-Metal Sulfur Ylide Complexes, XXVIII. - Reactivity of Phosphaalkenyl and Phosphavinylidene Complexes of Molybdenum and Tungsten towards the Sulfur Ylide Me,S(O) = CH2. X-ray Structure Analysis of The phosphavinyliden complexes (η5-C5H5)(CO)2M=P=C(SiMe3) 2 [3, M = Mo (a); W (b)] react with equimolar amounts of sulfur ylide Me2S(O)=CH2 (2) to afford the red metallophosphane-substituted sulfur ylides (η5-C5H5)(CO)2M=P[CH-(SiMe3 2][CH=S(O)Me2] (5a, b). Compounds 3a, b as well as 5a, b are trans-formed to the metallaheterocycles (η5-C5H5)- (6a, b) by excess of ylide. Constitution and configuration of 5 and 6 were established by spectroscopic means (IR, 1H, 13C, 31P NMR and MS). In addition, the molecular structure of 6a was elucidated by single crystal X-ray diffraction analysis.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 230
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 779-782 
    ISSN: 0009-2940
    Keywords: Cyclotetrasilazanes / Ring contraction / Cyclotrisilazanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ring Contractions of Octamethylcyclotetrasilazanes to Silyl-Substituted CyclotrisilazanesReaction of the mono- and dilithium derivatives of bis(fluorsilyl)-substituted cyclotetrasilazanes with fluorosilanes and fluoroboranes leads to ring contraction with formation of cyclotrisilazanes (1 - 8). The isomerisation is proved by the crystal structure determination of 1 and by NMR spectroscopy.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 231
    ISSN: 0009-2940
    Keywords: Thiophosphinitomanganese complexes / Cyclocotrimerization / Thiophenes / Furans / Phospholes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metal-Containing Heterocycles: Preparation, Properties, Reactions. LXIX It. - Independent Mechanisms of the Cyclocotrimerization of Thiophosphinito Manganese Complexes with Alkynes. - An Easy Access to Five-Membered HeterocyclesIn solution the dimeric thiophosphinitomanganese complexes (1), Et (2), nPr(3)] are in equilibrium with the monomeric species . For R1= iPr (7) and CY (8) the complexes are kinetically stabilized. In THF 4 - 8 react with different activated alkynes R2C≡CR2 to from the S-isomeric five-membered heterocycles (11a, b, e-i). With additional alkynes R2C≡CR2, 11a, b, e-i are trans membered heterocycles (10g to i are also obtained. In n-hexane, the P-isomeric seven membered thiaphosphamanganacycloheptadiens (14g-K) are formed in a [2 + 2 + 2) cycloaddition of 7, 8 to two molecules of R2C≡CR2. at elevated temperatures 14g-K eliminate CO with formation of the bicyclic compounds 12g-k. the action of MeC≡CCO2Me on 8 affords the seven-membered ring 15 in a regiospecific [2 + 2 +2] cycloaddition. 12a-d, h, i and 15 are starting compounds for easy access to the different substituted thiophenes 17, 18a-d, furans 19 h, i, and hte phosphole complexes 20a, b, h, i.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 232
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 887-893 
    ISSN: 0009-2940
    Keywords: Wagner-Meerwein rearrangement / Hlydride shift / Carbocations, Bridged / Conformational effects ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Rearrangements of 6-Bicyclo[3.2.l]octyl Cations6-Bicyclo[3.2.1]octyl cations were generated by nitrous acid deaminations of the amines 12, 14 and by acetolyses of the tosylates 9, 20. the major products are bicyclo[3.2.1]octan-exo-6-ol (17), bicyclo[3.2.1]octan-exo-2-o. (18), and bicyclo[2.2.2]octan-2-ol (19). 4,6(4,5) hydride shifts account for the formation of 18 and 19. The product distributions indicate substantial kS contributions for he endo precursors while the exo precursors react almost exclusively by way of carbocations, as confirmed by the ring expansion of bicyclo[4.1.1]octane-2-di-azonium ions (30. The product distributions obtained from the exo-diazonium ion 15n and from the exo-tosylate 20 are rather similar, but hte distributions of a deuterium label differ strongly. Dediazoniation of 15 leads to a highly unsymmetrical intermediate, whereas acetolysis of 20 involves an effectively equilibrated species. These findings cannot e interpreted in terns of open ions. Unsymmetrically bridged ions, whose conformational equilibration competes with substitution and hydride shifts, provide a consistent explanation.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 233
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 967-970 
    ISSN: 0009-2940
    Keywords: Cyclopentadiene, pentamethyl- ; Benzene, 1,2,4,5-tetramethyl- ; o-Xylene ; Boron compounds, subvalent ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Addition and Insertion Reactions of Subvalent Boron Species with Aromatic CompoundsDichloro(diisopropylamino)borane reacts with pentamethyl-cyclopentadienide providing the substitution product 1. A suspension of a sodium-potassium alloy in 1,2-dimethoxyethane and 1,2,4,5-tetramethylbenzene reacts with difluoro(diisopropylamino)borane to give 1,4-bis[fluoro(diisopropylamino)-boryl]-2,3,5,6-tetramethyl-2,5-cyclohexadiene(3). If o-xylene is used instead of 1,2,4,5-tetramethylbenzene in this reaction, 1,4-bis[fluoro(diisopropylamino)boryl]-2,3-dimethyl-2,5-cyclohexadiene (4) is the main product; however, the bicyclic compound 5 is also formed by formal insertion of two aminoborene units “BNR2” into the carbon skeleton and by addition of two (FBNR2) units. The compounds are characterized by elemental analyses and spectroscopically [MS, NMR (1H, 11B, 13C, 19F)]. An X-ray structure analysis of 5 is presented.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 234
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 983-987 
    ISSN: 0009-2940
    Keywords: Hydrogenation, catalytic ; Arenes ; Lithium tetrahydroaluminate ; Titanium tetrachloride ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Treatment of anthracene (A) with LiAlH4 (LAH) at 150°C under atmospheric pressure gives 9,10-di- and 1,2,3,4-tetrahydroanthracene (2H-A and 4H-A). At 160-200°C and under hydrogen pressure (10-90 bar) a number of simple and polycyclic aromatic compounds [e. g. toluene, naphthalene (N), A, phenanthene (PH), and pyrene (PY)] are converted to fully or partially hydrogenated arenes. Addition of small amounts of TiCl4 or TiCl3 and the choice of solvents (heptane or glymes) have marked effects on the reaction. The pair triethylaluminium/TiCl4 acts also as efficient hydrogenation catalyst.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 235
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 953-961 
    ISSN: 0009-2940
    Keywords: N-Boryl amino acid esters ; N,N-Dimethyl amino acid boryl esters ; N-Boryl amino acid boryl esters ; 1,3,2-Oxazaborolidin-5-on derivatives ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Contributions to the Chemistry of Boron, 2021). - Borylation of Amino Acids by an Amino-imino-boraneReactions of (tert-butylimino)(2,2,6,6-tetramethylpiperidino)-borane (3) with amino acid esters or N,N-dimethyl amino acids lead to the N-borylated products 5 and boryl esters 11, respectively. Amino acids and 3 yield the O,N-bis-boryl compounds 13 and/or 1,3,2-oxazaborolidin-5-ones 14, depending on the size of the organyl substituent R at the α-carbon atom of the amino acid. Increasing the bulk of this group favours the formation of 14 with elimination of tert-butylamine. The five-membered OBNCC ring of 14 is planar according to an X-ray structure analysis of 14e. (2,6-Diisopropylphenylimino)(2,2,6,6-tetramethylpiperidino)borane reacts with amino acids similar to 3, but tetramethylpiperidine is eliminated on ring formation to produce 20. N-Monoalkyl amino acids and 3 predominantly give oxazaborolidin-5-ones.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 236
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1039-1041 
    ISSN: 0009-2940
    Keywords: Fluorosilylamides of K, Na ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Sodium and Potassium Fluorosilylamides - Synthesis and Crystal Structurestert-Butyl(di-tert-butylfluorosilyl)amine (1) reacts with sodium or potassium to give the alkali salts 2 or 3, respectively. 2 and 3 crystallize as THF adducts and form head-to-tail dimers. Sodium is tetracoordinated in 2 and potassium hexacoordinated in 3. The crystal structures of the alkali salts are discussed.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 237
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1063-1070 
    ISSN: 0009-2940
    Keywords: Carbonylation of 1,4-dienes ; Catalysis, cobalt and rhodium ; Cyclopentenone derivatives ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Hydrocarbonylating Cyclization of Dienes, 81. - Cyclization of 1,4-Dienes with Functional Groups in 3-Position1,4-Dienes 1a-i with functional groups at C-3 were synthesized and treated under the conditions of metal-catalyzed hydrocarbonylating cyclization. Under the usual conditions no cyclization products could be isolated. Modifications of the reaction conditions did not lead to the expected cyclopentanones of type 2 or 3 either. Instead, the original functional groups are split off. Depending on the reaction conditions, either the non-functionalized 2-cyclopentenones 5, the cyclopentanones 6, or the 2-cyclopentenones 7 with a functional group introduced from the solvent into the 2-methyl group are obtained. These unexpected products of type 7 at least formally correspond to allylic rearrangement products of the expected but not observed type-3 exo-methylenecyclopentanones. The mechanism of the formation of these products is discussed.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 238
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1029-1038 
    ISSN: 0009-2940
    Keywords: Antitumor activity ; 1, 2-Diaminoethanes ; P388 Leukemia ; Platinum(II) complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Twelve new diamine ligands are synthesized and characterized in which a benzyl group and another vicinal substituent or a benzyl group, a 4-Cl-benzyl group, and a 4-MeO-benzyl group, respectively, and two other geminal substituents are attached to the 1,2-diaminoethane skeleton. The diamine ligands are transformed into the dichloroplatinum(II) complexes. The chloride ligands of four complexes are replaced by the lactate anion, α-Cyclodextrin and polyvinylpyrrolidone are used to increase the water solubility of the Pt(II) complexes. The antitumor activity of the Pt(II) complexes is tested towards the P388 leukemia. The compounds with small alkyl substituents show antitumor activities which are much higher than the antitumor activity of cis-platinum. Compared to the insoluble dichloro complexes, the lactate complexes and the formulations with α-cyclodextrin and polyvinylpyrrolidone exhibit good water solubility, and no decrease of the antitumor activity is observed.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 239
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1053-1061 
    ISSN: 0009-2940
    Keywords: Carbonylation of 1,4-dienes ; Cyclopentanone synthesis ; Catalysis, functional groups in ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Hydrocarbonylating Cyclization of Dienes, 71. - Cyclization of 1,4-Dienes Containing Functionalyzed Side Chains at C-3In order to test, whether functional groups are tolerable in rhodium- or cobalt-catalyzed hydrocarbonylating cyclizations of 1,4-dienes 1 to substituted cyclopentanones 2, various dienes of type 3 with functionalyzed side chains in C-3 were synthesized and treated under cyclization conditions. Ester, hydroxy, alkoxy, and acetate groups proved to be sufficiently stable (the latter only in rhodium-catalyzed conversions), so that the corresponding cyclopentanones 4 could be obtained in medium to good yields. Free carboxylic acid and aldehyde groups, however, prevented the formation of significant amounts of cyclization products. Pentenynes of type 6 under analogous conditions yielded at best only minor amounts of cyclopentanones.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 240
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 241
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1221-1226 
    ISSN: 0009-2940
    Keywords: π-Complexes of p-block elements ; Arene complexes ; Arsenic complexes ; Antimony complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1,2,4,5-Tetramethyl-and pentamethylbenzene from stable 1:2 complexes with SbCl3 of the type (C6H6-Men) · 2SbCl3(1,2) with an inverse sandwich structure. The compounds crystallize isotypically and are isostructural to the (hexamethylbenzene)antimony and -bismuth complexes.They are thus built of tetrameric chlorine-bridged Sb4Cl12 units, which are crosslinked at the metal centers with four other tetramers by double-sided arene coordination (X-ray structure analysis of 1). The Sb atoms, which are in a distorted trigonal bipyramidal environment, show a slight deviation from a centric (η6) coordination. The same stoichiometry and the same structural principle are found for the complex (C6Me6 · 2 AsCl3 (4), which is obtained from solutions of hexamethylbenzene and AsCl3 in toluene. In 4 the arsenic atoms are η6-coordinated to the hexamethylbenzene ring from both sides (X-ray analysis). Treatment of AsBr3 with hexamethylbenzene leads to a product of the composition 5 (C6Me6) · AsBr3. Reaction of hexaethylbenzene with AsCl3 in petroleum ether leads to the formation of the 1:2 complex (C6Et6) · 2 AsCl3 (5), built of discrete inverse sandwich units, which are arranged in strings parallel to the crystallographic c axis. From solutions of AsCl3 (AsBr3), SbCl3 (SbBr3) and hexaethylbenzene in petroleum ether ternary compounds are isolated with an As:Sb ratio of 1:5.2 and 1:1.86, respectively. Single crystal X-ray structure determinations failed as a consequence of severe disorder.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 242
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1375-1380 
    ISSN: 0009-2940
    Keywords: Cross-conjugated alkynes ; Alkadienynes ; Pyrolysis, gas-phase ; Cycloisomerization ; Vinylidenecarbenes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On the Gas-Phase Pyrolysis of 2-Ethinyl-1.3-butadiene and Its Thermal CycloisomerizationThe gas-phase pyrolysis of 2-ethinyl-1,3-butadiene (2) has been investigated in the 500-to-700°C temperature range. Besides several fragmentation products (≤C4 hydrocarbons) benzene and fulvene (5) are the main products. Under the same conditions 2-([2-D1]ethinyl)-1,3-butadiene (2a) furnishes the monodeuteriofulvenes 5a-c. The cycloisomerization of 2/2a presumably begins with an acetylene-vinylidenecarbene rearrangement, which may be followed by a deuterium scrambling mechanism involving either benzvalene (9) or vinylcyclobutadiene (10) intermediates. When 1-ethinyl-1-cyclohexene (6) is employed as a precursor for 2, styrene is produced in significant amounts besides the products observed from 2. Pyrolysis of 1-([2-D1]ethinyl)cyclohexene (6a) provides [D1]-styrene whose isotopic label is scrambled over both the vinyl substituent and the aromatic nucleus.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 243
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1403-1409 
    ISSN: 0009-2940
    Keywords: β-Ketoamides ; Enols ; (Z)/(E) Equilibria ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: (E)- and (Z)-Enols of β-Ketocarboxylic Acid AmidesReaction of dimesitoyldiazomethane (1) with ammonia (3a), primary and secondary amines (3b - o and 3p - v, respectively) leads to the completely enolized amides 4a - v. Besides the chelated Z configuration the unusual E isomer exists in the most cases, too. The Z/E distribution in the equilibrium depends on the steric and electronic effects present in the amide group CONR2R3 and on the solvent.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 244
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1433-1435 
    ISSN: 0009-2940
    Keywords: Diazonium ion ; Crown complexation ; Cluster ions ; Collisional dissociation ; Acid-base chemistry ; Mass spectrometry ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The molecular complexes (cluster ions) formed between various aromatic diazonium ion salts ArN2⊕BF4⊖ and 18-crown-6 host molecules are studied by FAB mass spectrometry. The nature of the interaction is probed by MS-MS experiments in which the ArNF (crown) 1:1 complexes are mass-selected and subjected to collisionally activated dissociation (CAD), using helium as collision gas. The results suggest that acid-base chemistry (proton and hydride transfer) occurs within the guest -host complex. Precedented mechanistic pathways for ArN2⊖ dediazoniation in the condensed phase are used as guidelines to explain these observations.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 245
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1449-1451 
    ISSN: 0009-2940
    Keywords: Sulfurization ; Lawesson's reagent ; β-Lactone, α-methylene ; β-S-Thiolactone, α-methylene ; Oxetane ; Thietane ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An α-methylene β-S-thiolactone, a new sulfur heterocycle, is prepared by sulfurization of the corresponding α-methylene β-lactone using Lawesson's reagent as sulfur source.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 246
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1485-1485 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 247
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1343-1344 
    ISSN: 0009-2940
    Keywords: Nitrogen iodine chemistry ; (Iodocyano)iodonium ion ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Characterization of (lodocyano)iodonium Hexafluoroarsenate. [ICNI]⊕[AsF6]⊖(Iodocyano)iodonium hexafluoroarsenate, [ICNI]⊕[AsF6]⊖ (1), was synthesized quantitatively by the reaction of iodine cyanide with [I3]⊕[AsF6]⊖ and was characterized by chemical analysis, IR, Raman and 19F-NMR data. The [ICNI]⊕ cation in 1 represents the first example of its kind which is stable at room temperature, formally containing an N⊕-I bond.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 248
    ISSN: 0009-2940
    Keywords: Benzyl alcohols, dehydrogenation ; tert-Butyl hydroperoxide ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Primary and secondary benzyl alcohols are selectivity converted in high yields into the corresponding aldehydes or ketones using tert-butyl hydroperoxide and catalytic amounts of titanium or (better) zirconium alcoholates. Aliphatic hydroxy groups, double bonds (except those in allylic position to hydroxy groups), and phenolic hydroxy groups (except those in ortho position to the benzylic alcohol) are not attacked.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 249
    ISSN: 0009-2940
    Keywords: Diels-Alder reaction ; Vinyl allenes ; Acetylenecarboxylates ; Phosphonates ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1,5-Sigmatropic Rearrangements of Diels-Alder Adducts in the Reaction of Alkatrienylphosphonates with Alkyl Acetylenecarboxylates - A New Method for the Synthesis of Benzyl- and PhenylphosphonatesThe reaction of dialkyl (3-methyl-1,2,4-pentatrienyl)- and dialky] (3-methyl-1-vinyl-1,2-butadienyl)phosphonic acids 1a-d an 5a, b, respectively, with alkyl esters of the acetylenecarboxylic acids 2a-d proceeds via 1,5-sigmatropic rearrangement and aromatization of the initially formed Diels-Alder adducts. The reaction with the unsymmetrical dienophiles 2a, b occurs with preferred formation of the cycloadducts A, leading to the benzylphosphonates 3a-h. The above reaction constitutes a new method for the preparation of difficulty accessible derivatives of the benzyl- and phenylphosphonic acids. The aromatic structures of the obtained compounds 3a-h, 4a-f, and 6a-d were proved by their IR, mass, and 1H-NMR spectra.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 250
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 251
    ISSN: 0009-2940
    Keywords: Ruthenium complexes ; Ether-phosphines ; O-Basicity ; Fluxional behavior ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Novel Basic Ligands for the Homogeneous Catalytic Carbonylation of Methanol, XXVIl). - Dynamic and Reactive Behaviour of (Ether-Phosphane)Ruthenium(II) Complexes in Dependence on the o-BasicityReaction of the ether-phosphane ligand Ph2PCH2C4H7O2 (3a) with Cl2Ru(PPh3)3 (2) results in the formation of the bis(chelate) complex trans-Cl2Ru(P^O)2 (4a). (P∼O = η1—P-coordinated; P^O = η2—O,P-coordinated). With CO both Ru-O bonds are cleaved to give all-trans-Cl2Ru(CO)2(P∼O)2 (7a). At 35°C 7a is transformed into the monocarbonyl ruthenium complex trans-Cl2(P^O)(P∼O)RuCO (5a) with elimination of one CO molecule. On heating all-trans-7a to 110°C in toluene the thermodynamically more stable complex cis-Cl2(OC)2Ru(trans-P∼O)2 (6a) is obtained. All reaction steps are reversible. Upon irradiation cis,cis,trans-6a is retransformed at 40°C into 4a via all-trans-7a and 5a. The latter and the corresponding complexes 5b, c, containing THF and CH2OCH3 as ether substituents, show fluxional behaviour. The coalescence temperatures (10, 80, and 55°C, resp.) and the estimated ΔG≢ values (52, 65, and 59 kJ/mol, resp.) of the exchange process indicate the weakest Ru-O contact in 5a compared to 5b, c. The lower basicity of the dioxanyl function is also responsible for the different reaction behaviour of 4a, 5a, and 7a compared to the corresponding complexes with the ligands 3b, c.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 252
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1447-1448 
    ISSN: 0009-2940
    Keywords: Vinyl esters ; 1,3-Dioxan-4-ones, 5-methylene- ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Vinyl esters such as 2, in the presence of DABCO, undergo intial reaction with aldehydes, followed by nucleophilic attack on a second aldehyde molecule. Subsequent intramolecular transesterification affords the dioxanones 5 in high yields and high diastereomeric excesses.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 253
    ISSN: 0009-2940
    Keywords: Heterocumulenes ; Thione S-imide ; Isothiazolidine ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Preparation of the First Thione S-Imides with Perfluoromethyl Groups by the Use of Sodium Hexamethyldisilazanide as a Mild Dehydrohalogenation ReagentFrom the reaction of the sulfenyl chloride 1 with the monosilylated amines 2a, b the sulfenamides 3a, b are obtained in good yields. 1,3-Dehydrohalogenation of 3a, b with sodium hexamethyldisilazanide yields the thione S-imides 5a, b. Imide 5a reacts with norbornene (6) to produce the isothiazolidine derivative 7. The structures of 5b and 7 are confirmed by X-ray analyses.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 254
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1461-1468 
    ISSN: 0009-2940
    Keywords: Silver complexes ; Copper complexes ; Dialkyne ligands ; 1,6-Cyclodecadiyne ; 1,7-Cyclododecadiyne ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Silver(1) and Copper(1) Complexes of 1,6-Cyclodecadiyne and 1,7-CyclododecadiyneThe reactions of 1,6-cyclodecadiyne (1), 1,7-cyclododecadiyne (2), and 1,8-cyclotetradecadiyne (3) with silver(I) triflate and copper(I) triflate yield colourless crystals: [C10H12·AgCF3SO3]n (4), [C10H12·CuCF3SO3]n(5), [C12H16·AgCF3SO3]n (6), [C12H16·CuCF3SO3]n (7), and [C14H20·AgCF3SO3]n (8). The spectroscopic data of 4-8 indicate a weak interaction between the triple bonds and the metal ion. In the crystal structure of 4 double-strands of 1,6-cyclodecadiyne rings in the chair conformation are coupled by Ag(CF3SO3)2Ag units to form a two-dimensional network. The X-ray analysis of single crystals of 6 and 7 reveals twelve-membered rings that are connected by silver or copper ions, respectively. Each triflate ligand in 6 and 7 uses two of its oxygen atoms to coordinate two different metal centers. The result is a complex three-dimensional network. In the case of the silver complex 8, the X-ray analysis also exhibits a similar polymeric structure. Only slight differences of the structural parameters are observed on comparison of the free cyclic dialkyne and that bound to a metal in 4, 6, and 7. The conformation of the 10- or 12 membered rings in 1 and 2 are more or less identical to those in 4 or 6 and 7.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 255
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1481-1484 
    ISSN: 0009-2940
    Keywords: Alkylidyne complexes ; Clusters ; Halogen exchange reaction ; Iron complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Nonacarbonylbis(μ3-methylidyne)triironHalogen exchange reaction in Fe3(CO)9(μ3—CF)2 (1) with BBr3 (3) yields Fe3(CO)9(μ3—CBr)2 (4), which can be converted by (C4H9)3SnH (5) into Fe3(CO)9(μ3—CH)2 (6). 6 is the parent compound of the bis(alkylidyne)triiron clusters. Selective reduction of the CBr moiety in Fe3(CO)9(μ3—CBr) (μ3—CCO2CH3) (7) results in the formation of Fe3(CO)9(μ3—CH) (μ3—CCO2CH3) (8). The structure of 8 has been elucidated by an X-ray crystalstructure determination.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 256
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1575-1578 
    ISSN: 0009-2940
    Keywords: 5-Tetrazolamines, 1-(methylenamino)- ; Dimroth rearrangement ; (5-Tetrazolyl)hydrazones ; Cyanohydrazones, reaction with hydrogen azide ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dimroth Rearrangement of Imines Derived from 1,5-DiaminotetrazoleHeating the imines 1 in dimethyl sulfoxide (or partly in xylene) provides hydrazones such as 2. The reaction is greatly favoured by electron-withdrawing groups attached to the imine carbon atom.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 257
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1583-1586 
    ISSN: 0009-2940
    Keywords: Transition-metal ions ; Bond activation, CH and CC ; Olefine activation ; Tandem mass spectrometry ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mechanistic details (i.e. β-versus γ-hydrogen transfer) of transition-metal ion induced generation of propene from metastable ion complexes of 1,7-octadiene with M+=Cr+, Fe+, Ni+ are strongly affected by the nature of M+. For Cr+ the major reaction involves the transfer of an allylically activated hydrogen atom to M+ (γ-H transfer), followed by coupling of this hydrogen with the C3H5 unit (Scheme 3: 8 → 9→ 11 → C3H6). The hydrogen transfer 9→ 11 is preceded by substantial exchange reactions. A minor path for M+=Cr+ corresponds to the more traditional β-hydrogen transfer 9→ 10. This process, however, represents the major route for propene loss induced by M+ = Fe+, Ni+.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 258
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1579-1582 
    ISSN: 0009-2940
    Keywords: Calculations, PM3 ; Phenoxathiine ; Proline ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Structure of N,N′-(Phenoxathiine-4,6-dicarbonyl)bis(proline methyl ester) - Conformation in the Crystal, in Solution, and According to Semiempirical MethodsThe title compound 1 is synthesized by coupling phenoxathiine-4,6 -dicarboxylic acid (2) with proline methyl ester. An improved synthesis of 2 is presented. The conformation of 1 in the crystal structure and in solution is discussed. The geometry of the product is investigated by semiempirical methods.The conformative hypersurfaces (Ramachandran diagrams) of N-acetylproline methyl ester and N-acetylproline methylamide are calculated with PM3.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 259
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1885-1889 
    ISSN: 0009-2940
    Keywords: Pyrimidine derivatives ; Sulfur extrusion, photolytic ; Pyrimidinophanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The title compounds 1 and 2 are synthesized by photolytic sulfur extrusion from the 2,11-dithia[3.3](2,5)pyrimidinophane 17. The molecular structures of 1 and 2 are determined by X-ray structure analysis and are discussed with regard to the steric strain in these molecules. Thermolysis of [(5-methyl-2-pyrimidinyl]methyl]- or [(2-methyl-5-pyrimidinyl)methyl]-trimethylammonium hydroxide (10 or 11) does not generate 1 and 2. α-Chlorination of 2,5-dimethylpyrimidine (3) with N-chlorosuccinimide provides the required precursors 4-6.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 260
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 261
    ISSN: 0009-2940
    Keywords: Dihydroanthracene ; Dihydroanthracene, butyl-substituted ; Tricarbonylchromium ; Chromium complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The complexes [9,10-dihydroanthracene][tricarbonylchromium]n [9,10-DHA][Cr(CO)3]n [n = 1 (1), 2 (2)] and the related mono- and bis(tricarbonylchromium) complexes of 2,6- and 2,7-di-tert-butyl-9,10-dihydroanthrancene [2,6-DB-9,10-DHA][Cr(CO)3]n [n = 1 (3), 2 (4)] and [2,7-DB-9,10-DHA][Cr(CO)3]n [n = 1 (5), 2 (6)] have been prepared by heating the 9,10-DHA species in the presence of hexacarbonylchromium [Cr(CO)6]. Evidence for the existence of the complex [2,6,9-tri-tert-butyl-9,10-DHA][Cr(CO)3] (7) is also presented. The complexes have been characterised spectroscopically, and for complex 1 an X-ray crystallographic structure determination has been carried out. This complex adopts the unexpected structure in which the non-coordinated arene ring is bent towards the Cr(CO)3 moiety. The syntheses and spectroscopic characterisations of 2,6- and 2,7-di-tert-butylanthracene (2,6- and 2,7-DBA), 2,6- and 2,7-di-tert-butyl-9,10-dihydroanthracene (2,6-and 2,7-DB-9,10-DHA), 2,6,9-, 2,7,9-, and 2,7,10-tri-tert-butyl-9,10-dihydroanthracene (2,6,9-, 2,7,9- and 2,7,10-TB-9,10-DHA), and 2,6,9,10- and 2,7,9,10-tetra-tert-butyl-9,10-dihydroanthracene(2,6,9,10- and 2,7,9,10-TeB-9,10-DHA) are also given.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 262
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1971-1974 
    ISSN: 0009-2940
    Keywords: Alkylidyne ligands ; Rhenium complexes ; Metal-metal multiple bonds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Multiple Bonds Between Main-Group Elements and Transition Metals, LXXXII.  -  Dinuclear p-Benzylidyne Complexes Having a Double Bond between Rhenium AtomsThe dialkylrhenium(V) complex (η5-C5Me5)Re(=O)(CH2Ph)2 (3) reacts with the organotitanium reagents (η5-C5H5)TiX3 (X = Cl, Br) to yield the dinuclear rhenium(IV) complexes (η5C5Me5)2 Re2X3(CC6H5) (4a, b). According to a single-crystal X-ray diffraction analysis, 4a′ (C5Me4Et in place of C5Me5) represents one of the few known examples of μ-alkylidyne complexes that have metal-to-metal multiple bonds. The molecule of C2 symmetry has a planar four-membered Re,Cl,Re′,C-ring geometry and two trans-oriented sets of ligands. Very small angles at the bridging chloro ligand and alkylidyne carbon atom result from the short metal-metal distance (double bond).
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 263
    ISSN: 0009-2940
    Keywords: Episulfones ; Thiirane 1,1-dioxides ; Alkenes ; Sulfines ; Sulfonylsulfene-amine S,N-adducts ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Secondary Reactions of Sulfenes from Sulfonyl Chlorides and Tertiary Amines, 2.  -  Formation of Episulfones, Sulfonylsulfene  -  Amine S.N-Adducts. and Chlorosulfines from Primary Sulfonyl Chlorides and Tertiary AminesThe reaction of primary sulfonyl chlorides 1b-m with the tertiary amine bases quinuclidine, DABCO, Me3N, Et3N, Bu3N, EtiPr2N, and 1,2,2,6,6-pentamethylpiperidine is studied in acetonitrile solution between - 40 and 80°C. The 2,3-dialkylthiirane 1,1-dioxides 4 (trans/cis 〉 1) and the alkenes 5 [(E)/(Z) 〉 1] are obtained in high yields with Et3N at - 40°C. The stereochemistry is influenced by the amine base B in the ring closure reaction and partially by epimerization of the episulfones 4. Hindered bases favor the cis, β-branched sulfonyl chlorides the trans isomer. Competing formation of the sulfonylsulfene-amine S,N-adducts 7 is only observed with quinuclidine, DABCO, and Me3N, which are also the most active amines in the epimerization of the cis-2,3-diarylthiirane 1,1-dioxides 4. Methanesulfonyl chloride (1a) yields the mesylsulfene-amine S,N-adducts 7a with Me3N and Et3N in MeCN, but thiirane 1,1-dioxide (4a) with EtiPr2N in MeCN or with Et3N in Et2O. Formation of chlorosulfines 10 is favored by higher temperature (T 〉 20°C), hindered amine bases and β-branched sulfonyl chlorides. Isolation of 10g and 10h in high yields shows that tert-alkylchlorosulfines are rather stable sulfines.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 264
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1749-1752 
    ISSN: 0009-2940
    Keywords: Tetraaza [3.2.3.2] metacyclophane ; Transition-metal carbonyl complexes ; Photoisomerism ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2,19-Dioxo[3.3](3,3′)azobenzolophane (5) has been obtained in a total yield of 18% by way of CO insertion and cyclization of 1,2-bis[3-(bromomethyl)phenyl]-4,4-dimethyl-3,5-pyrazoli-dinedione (1) using Co2(CO)8 in acetonitrile followed by the removal of the N-protecting 4,4-dimethylmalonyl groups. 5 is obtained predominantly as the trans / trans isomer 5a and can be isomerized by irradiation with λ=369 nm to a mixture of nearly equal amounts of the trans / trans, cis / trans, and cis / cis isomers 5a, 5b and 5c. The thermal isomerization back to 5a is slow but fast upon irradiation with λ=443 nm.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 265
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 2173-2180 
    ISSN: 0009-2940
    Keywords: Allenes ; 1,6-Addition ; Organocuprates ; Protonation, regioselectivity of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ten β-allenic esters, ketones, and thioesters 15 bearing alkyl, alkenyl, aryl, and trimethylsilyl groups are synthesized in 57- 85% yield by 1,6-addition of organocuprates to polarized enynes 10. The dependence of the regioselectivity of the protonation of the allenyl enolate intermediate 7 on the protonating agent is studied: pure allenes are obtained by quenching the intermediate with pivalic acid at -80°C. The method is applied in a short synthesis of pseudoionone (18).
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 266
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 2203-2206 
    ISSN: 0009-2940
    Keywords: Imidazolidine ; Dicyanoacetates ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of Imidazolidine Derivatives from DicyanoacetatesBy nucleophilic additions of amino acids to one cyano group of salts of alkyl dicyanoacetates 1 followed by ring-cyclisation reactions the 4-imidazolidinone derivatives 3, 5 are obtained.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 267
    ISSN: 0009-2940
    Keywords: 1,3,5-Triaza-2,4-diphospha-1,4-Pentadienes, dynamic behavior ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis, Molecular Structure, and Dynamic Behaviour of 1,3,5-Triaza-2,4-diphospha-1,4-pentadienesChloro(arylimino)phosphane (1) reacts with the 1,3-diaza-2-phosphaallylic system 3 to form 1,3,5-triaza-2,4-diphospha-1,4-pentadienes Ar-N=P-N(R)-P=N-Ar (Ar = 2,4,6-tBu3-C6H2; R = tBu, 2,4,6-iPrc3C6H2) (4a-c). the molecular structure of 4a (“Exo-endo-S conformation”) as well as the dynamic behaviour of the compounds in solution are discussed. the observed temperature dependance of the NMR spectra of 4c was interpreted as a sigmatropic 1,3-rearrangement followed by a P-N rotation.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 268
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 847-853 
    ISSN: 0009-2940
    Keywords: Phosphines, optically active / Nickel complexes / Hydrogenation, enantioselective / Grignard cross coupling, enantinoselective / Gas chromatography, enantioselective ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Asymmetric Catalysis, LI. - New Optically Active Chelating Phosphines - Synthesis and Application in Enantioselective CatalysisThe known triphosphines 1 and 4 were transformed into their monophosphine oxide and monophosphine sulfide derivatives 2, 3, 5, and 6 via NiCl2 complexes. 21 optically active phosphines were used as ligands in the Rh-catalysed hydrogenation of (Z)-α-acetamidocinnamic acid and itaconic acid as well as in the Ni-catalysed cross-coupling reaction of phenylethylmagnesium chloride with vinyl bromide. The optical inductions of the Grignard cross coupling reaction were determined the first time by enantioselective gas chromatography.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 269
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1301-1306 
    ISSN: 0009-2940
    Keywords: 1,3,2-Diazaborinies, dihydro- ; Protonation ; Calculations, AMI, 4-31G ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Vinamidine Boron Chelate CompoundsThe chelate compound 7 is obtained by the reaction of the vinamidine 6 with Et2O - BF3. Protonation with HBF4 gives the cation 11. Comparison of the calculated and experimentally determined structures demonstrates 7 and 11 to be heterocyclic analogues of the cyclohexadienide 5 and 1,4-cy-cyclohexadiene (12).
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 270
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1319-1321 
    ISSN: 0009-2940
    Keywords: Chromium fluorides ; Matrix-isolation spectroscopy ; Combustion with fluorine ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Spectroscopic Studies of Higher Chromium Fluorides. Controversy over the Existence of Chromium Hexafluoride, CrP6Combustion of chromium with fluorine under various conditions led always to CrF5 as the highest chromium fluoride. The properties of pure CrF5 have been reinvestigated and IR, UV spectra of the gas-phase molecule, and also the vapor pressure have been measured for the first time. Furthermore, it has been shown that the IR spectrum of matrix-isolated CrF5 is identical to the IR spectrum of CrF6 quoted in the literature. It appears, that in principle the existence of CrF6 is doubtful.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 271
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1335-1337 
    ISSN: 0009-2940
    Keywords: Phosphorus sulfides, 31P-NMR, MS/Thiophosphoryl bromide, dehalogenation of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New Results Concerning the “Phosphorus Monosulfide” (PS)xThe orange-yellow solid of approximate composition (PS)x obtained by dehalogenation of P(S)Br3 with Mg proved to be a mixture of phosphorus sulfides e.g. P4S3, P4S4, P4S5, P4S7, and insoluble polymeric material. It is suggested that the latter contains a network of triply connected P atoms, many of which are substituted by groups. The conclusions are based on the results of analytical, mass-spectrometric and 31P-NMR-spectroscopic findings.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 272
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1345-1346 
    ISSN: 0009-2940
    Keywords: Sulphur-nitrogen ring ; Titanium ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Adduct of a Five-Membered Trisulfurdinitrogen Dioxide Ring with Titanium TetrachlorideReaction of S6N4O4 with TiCl4 lead to [(S3N2O2)TiCl4]2 (2). Single crystals of 2 were obtained by recrystallization from liquid SO2. 2 forms chains of five-membered S3N2O2 rings connected by Ti2Cl8 units. The S2N2 part of the five-membered ring may be described as a 6-π electron system.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 273
    ISSN: 0009-2940
    Keywords: Hydridotris(1-pyrazolyl)borato ligand ; Pyrazolyl ligand ; Rhenium ; High-oxidation state ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The syntheses of the rhenium(VII) title compounds (pz)ReO3 (1) and [HB(pz)3]ReO3 (2) (pz = pyrazolyl) are described. An X-ray crystallographic study of 2 shows, that it has a monomeric structure.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 274
    ISSN: 0009-2940
    Keywords: Thiocarbene complexes of chromium and tungsten ; Addition of alkynes to thiocarbene ligands ; β-(Thioalkenyl)carbene complexes, preparation ; Disengagement of ligands of silica gel ; Thioenol ether, preparation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organic Syntheses via Transition Metal Complexes, 41 1. - Thioenol Ethers by Insertion of Alkynes into M = C Bonds of Thiocarbene Complexes and Disengagement of Ligands on Silica GelA first example of reactions between alkynes and thiocarbene complexes is described. Et2N—C=C—CCH3 (2) adds to (alkylthio)phenylcarbene complexes LnM=C(SR)C6H5 (1) [LnM = Cr(CO)5. W(WO)5; R=CH2CH=CH2, CH2C6H5, c-C6H11, t-C4H9, C6H5] with insertion of the C=C into the M=C bond to form stereoselectively [(E)-β-(alkylthio)alkenyl]aminocarbene complexes LnM=C(NEt2) - C(CH3)=C(SR)C6H5 [(E)-3a-g]. With tungsten, but not with chromium, small amounts of indanone derivatives 4-6 were also obtained. We describe a straightforward and efficient method for the disengagement of ligands from carbene chromium complexes 3 on silica gel. Metal residues remain attached to the solid phase, and products are isolated by elution. Depending on the reaction conditions, different thioenol ethers 7-9 were obtained. Thus (E)-3a-d on silica gel at ambient temperature under the influence of air give β-(alkylthio)propenamides O=C(NEt2)-C(CH3)=C(SR)C6H5 [(E)-] and β-(alkylthio)propenals O=CH-C(CH3) = C(SR)C6H5 [(E)-8]. Thermolysis of 3 on silica gel in the absence of oxygen leads to the formation of aldehydes 8 and 3-(alkylthio)-1-indanones 5. Thermolysis of 3 on silca gel in the presence of sulfur yields β-(alkylthio)propenethioamides 9 as the only products.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 275
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1397-1401 
    ISSN: 0009-2940
    Keywords: Dithiadiaza[n.n.2]meta- and -paracyclophan-enes ; Conformation ; Photoisomerization ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Trinuclear Dithiadiaza[3.3.2]cyclophan-enesThe following five trinuclear dithiadiazacyclophanes have been prepared by means of the rigid-group principle with a succinyl and dimethylmalonyl N,N′-protecting group, respectively, and the high-dilution technique: 2,11-dithia-19,20-diaza[3.3.2]-(1,4)(1,4)(1,4)cyclophan-19-ene (12), 2, 11-dithia-19,20-diaza[3.3.2]-(1,3)( 1,4)( 1,4)cyclophan-19-ene (13), 2,l l-dithia-19,20-diaza[3.3.2]-(1,4)(1,3)(1,3)cyclophan-19-ene (14), 2,11-dithia-19,20-diaza[3.3.2]-(1,3)(1,3)(1,3)cyclophan-19-ene (15), and 4,6-dimethyl-2,9-dithia-17,18-diaza[2.2.2]( 1,3)(1,3)(1,3)cyclophan-17-ene (16). These cyclophanes contain an azobenzene moiety bridged in the case of 12 and 13 in the para-positions by a benzene ring and two short links which forces 12 and 13 into a cis-azo configuration. 14 - 16 are bridged in the meta-positions of the azobenzene and can adopt a cis- and a trans-azo configuration, respectively. 14 - 16 are photoisomerized into the cis form by irradiation with γ = 369 nm. The isomerization back into the trans form occurs slowly thermally or rapidly by irradiation with λ = 443 nm.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 276
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1421-1431 
    ISSN: 0009-2940
    Keywords: Pentafulvene, derivatives ; Alkali metal-carbanion pair structure ; Cyclic voltammetry ; Electrochemistry ; Reversible pentafulvene protonation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The application of the principle of kinetic stabilization on vinylogous 6-(cyclopentadienyl)pentafulvenes 1 led to the synthesis of the di- and tetra-tert-butyl derivatives 7a - e and 8a - c. Their reactions with bases and acids form charged, heteroatom-free cyanine-type carbanionic 9a - e, 10a - e and carbocationic ll a - e, 12a - c species which were characterized with NMR and UV/Vis spectroscopy. Conclusions on the ion pair structures of the alkali metal salts 9a - e and 10a - c are drawn from the spectroscopic data. Additionally, in one case the behavior of the alkali metal salt 10b towards oxidants was studied by cyclic voltammetry and the structure of the corresponding hydrocarbon 8b was proved by X-ray structural analysis.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 277
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1443-1445 
    ISSN: 0009-2940
    Keywords: Amines, secondary ; Benzotriazole ; mannich reaction ; Grignard reagent ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new method has been developed for the selective conversion of primary aliphatic amines into unsymmetrical secondary amines by Grignard reaction of 1-[(alkylamino)methyl]-benzotriazoles 1. This method employs simple procedure and mild conditions, and is specific in that only monoalkylation of the primary amines results.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 278
    ISSN: 0009-2940
    Keywords: Phosphine-borane adducts ; Phosphinoboranes trimeric ; Spiro boron heterocycles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Combination of (Me3Si)3P and H3B·THF results in the formation of the known adduct (Me3Si)3P·BH3 (1). The complex undergoes dehydrosilylation above 100°C, and two ring compounds, [(Me3Si)2PBH2]3 (2) and P[(μ—H—B2—H2)]{(BH2)2[P(SiMe3)2]2}2 (3), are isolated. The crystal structures of the compounds are compared with those of other phosphinoboranes.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 279
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1479-1480 
    ISSN: 0009-2940
    Keywords: Oxime complexes ; Imidazolines ; Cobalt complexes ; Crown ethers ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The novel vic-dioxime 2 has been synthesized by reaction of the thiourea 1 with cyanogen N,N′-dioxide. The IR and NMR data indicate that 2 is the (E,Z) isomer. However, in the Co(III) complex of 2, the metal ion is coordinated to the nitrogen atoms of the vic-dioxime moiety as in the case of the (E, E) isomers.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 280
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1495-1506 
    ISSN: 0009-2940
    Keywords: Cross couplings, Ni-catalyzed ; Vinylbicyclo[1.1.0]butanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Nickel(0)-Catalyzed Cross Coupling Reactions of (Tricyclo[4.1.0.02,7]hept-1-yl)magnesium Bromide and Related Grignard Reagents with Aryl, Vinyl, and Alkynyl Halides(Tricyclo[4.1.0.02,7]hept-1-yl)magnesium bromide (1c) and similar Grignard reagents like 2c, 3a-d, and 4 were cross-coupled with a series of aryl, vinyl, and alkynyl chlorides or bromides in the presence of approximately 1% of [1,2-bis(diphenyl-phosphino)ethane]nickel dichloride (NidppeCl2) leading to bridgehead-substituted aryl-, vinyl-, and alkynylbicyclo[1.1.0]-butanes in varying yields.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 281
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1537-1544 
    ISSN: 0009-2940
    Keywords: Nitrilium salts ; N-Acylcyanamidium salts ; N-Acylamidinium salts ; 2-Azoniaallene salts ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Nitrilium salts (5a,b) dehydrate primary carboxamides (6a,b) to give nitriles (8a,b) and O-protonated carboxamides (7a,b). Secondary carboxamides (9a,b,e-g) add to nitrilium salts (5b-d) to furnish mixtures of tautomeric N-acylamidinium salts (10a-d, 11a,c). However, with the stable acetylcyanamidium salt 5d the primarily formed amidinium salts 10 either cyclize with elimination of water to yield s-triazinium salts (12f,g) or react with a further carboxamide to afford the N-acylamidinium salts 14e,f. At low temperatures formamides (9g,h) are dehydrated by 5d to give isonitriles, which add to an excess of 5d to furnish the oxazolidines 15g,h. The triazinium salts 12 are characterized by 1,4-addition of alcohols giving the new triazinium salts 16a-c. Tertiary carboxamides (17a-k) add to the nitrilium salts 5d-d to give N1-acyl-N1,N3,N3-substituted amidinium salts 18a-k. This reaction was extended to a vinylogous tertiary carboxamide (19) affording the cyanine dyes 20a,b.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 282
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1563-1570 
    ISSN: 0009-2940
    Keywords: Sulfene-amine adducts ; Amine-sulfene adducts ; 2-Trimethylammonio-2-propanesulfinate ; Episulfones ; Sulfones, α-chloro- ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Secondary Reactions of Sulfenes from Sulfonyl Chlorides and Tertiary Amines, 1. - On the Competing Formation of Sulfene - Trialkylamine S,N- and C,N-AdductsPhenylmethanesulfonyl chloride (1a) reacts with an excess of triethylamine in acetonitrile solution at -40°C to give stilbene episulfone (9a, 95%) via the phenylsulfene-triethylamine S,N-adduct 1ah. With trimethylamine and quinuclidine the yield of stilbene is reduced by the additional formation of (benzylsulfonyl)phenylsulfene-amines S,N-adducts 11ag and 11ae and C,N-adducts 15ag and 15ae which was proven by reaction with dimethylamine to 16 and by hydrolysis to 17-19, respectively. 1d reacts with triethylamine yielding 94% of α-chloro sulfones 4s and 6d via pentamethylenesulfene-triethylamine S,N-adduct 5dh, with trimethylamine, however, C,N-adduct 12dg is obtained which is easily oxidized to 20dg (47%). The air-sensitive dimethylsulfene-trimethylamine C,N-adduct 12cg was isolated and characterized.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 283
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1591-1594 
    ISSN: 0009-2940
    Keywords: Zeolite ; Microwave irradiation ; Claisen rearrangement ; Dehydrogenation ; Dehydration ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Microwave-Induced Reactions of Organic Substrates in the Cage of ZeolitesMicrowave irradiation of compounds 1, 7, 15, 19, 23, and 24adsorbed on Y zeolites has been studied. The reaction rate of the corresponding rearrangement, dehydrogenation and dehydration is dramatically enhanced as compared with reactions under thermal conditions.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 284
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 285
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1607-1616 
    ISSN: 0009-2940
    Keywords: Clusters ; Alkyne ligands ; Carbon-carbon coupling ; Oligomerization of alkynes ; Acylation, reductive ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions of μ3-Bridging Alkyne Ligands on Heterometallic ClustersThe metal-exchange methods to obtain alkyne-bridged heterometallic clusters from RuCo2(CO)9(μ3-RC≡C') (2) were improved, and the new clusters RuCoMoCp(CO)8(PhC≡CPh) (3c), RuCoNiCp(CO)6(MeC≡CPh) (5b), RuMoNiCp2(CO)5-(MeC≡CMe) (6a), and HFeRuMoCp(CO)8(MeC≡CMe) (7a) were obtained thereby. Some of the alkyne-bridged clusters were found to react with additional alkyne. One alkyne unit was incorporated in the products RuCoNiCp(CO)6(RC≡C')2 (9), two alkyne units were incorporated in the products Ru-Co2(CO)7(RC≡C')3 (8). In a side reaction, butyne was trimerized to hexamethylbenzene. Radical anions of the clusters FeCo2(CO)9(RC≡C') (1) were formed by reduction with cobaltocene. The reaction of these radical anions with alkylating reagents was accompanied by cluster fragmentation and CO insertion converting the former alkyne ligand by acylation into the new trisubstituted oxoalkenyl ligand in the products FeCo(CO)6(μ-CR=CR'-CR″=O) (11). The constitutions of the cluster types 7, 9 and 11 were confirmed by crystal-structure determinations.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 286
    ISSN: 0009-2940
    Keywords: Methylsodium (deuterated) ; Neutron diffraction ; Synchrotron radiation diffraction ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metal Alkyl and Aryl Compounds, 441) - Preparation and Structure of Methylsodium. Structure Determination using NaCD, Powders at 1.5 and 300 K by Neutron and Synchrotron Radiation Diffraction[D3]Methylsodium (NaCD3) has been obtained by the reaction of [D3]methyllithium with sodium tert-butoxide. Its crystal structure has been determined from NaCD3 powder samples using the combination of neutron and synchrotron radiation diffraction techniques. Studies at 1.5 and 300 K show a new structure type (orthorhombic, space group I222, Z=16). Na and C atomic positions have been obtained from synchrotron radiation data and subsequently D positions by neutron diffraction. The complete structure has been refined using Rietveld methods. - Half of the ions are arranged in tetramers, (NaCD3)4, similar to those in methyllithium. The orientation of the methanide ions with respect to the three next Na ions is staggered. The remaining 8 Na and 8 methanide ions interconnect the tetramers by Na-C contacts; their Na ions are arranged in zigzag chains. Thus, the structure of methylsodium shows elements of the methyllithium and methylpotassium structure. All methanide ions are trigonal-pyramidal with C-D 109 pm and D-C-D angles of 106° (1.5 K). Na-C distances vary from 253 to 291 pm, depending upon the methyl-Na orientation. IR data of NaCD3 are given.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 287
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1641-1648 
    ISSN: 0009-2940
    Keywords: Cyclopentadienyl ligand, functionalized ; Half-sandwich complexes ; Cobalt complexes ; Intramolecular C=C bond coordination ; Reductive complexation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermolysis of [1-(3-butenyl)-2,3,4,5-tetramethylcyclopentadienyl]carbonyldiiodocobalt, (η5-C5Me4CH2CH2CH=CH2)-Co(CO)I2 (2), in boiling octane affords the dimeric diiodide [(η5-C5Me4CH2CH2CH=CH2)-COI2]2 (3) without any interference of the 3-butenyl chain with the cobalt center. 2 reacts with various two-electron ligands L (L=P(OMe)3, P(OPh)3, PPh3, PMe3, PMe2Ph, tBuNC] to give a series of cobalt(III) complexes of the general formulae (η5-C5Me4CH2CH2CH=CH2)-Co(L)I2 (4-9). Sodium amalgam reduction of these “open-chain” complexes 4-9 yields novel cobalt(1) complexes containing an intramolecularly coordinated C=C bond (η5:η2-C5Me4CH2CH2CH=CH2)-Co(L). For L=CO (12), P(OMe)3 (13), and P(OPh)3 (14) low-melting crystals are isolated and fully characterized by analytical and spectroscopic methods.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 288
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1657-1659 
    ISSN: 0009-2940
    Keywords: Arsenic(V) cations, halogeno(methyl)- ; Arsorane, trifluoro(dimethyl)- ; Organoarsenic compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Characterization of Novel Halogeno(methyl)arsenic(V) Cations: [(CH3)2AsI2]⊕ [AsF6]⊖, [CH3AsI3]⊕ [AsF6]⊖ and [(CH3)2AsF2]⊕ [AsF6]⊖The two new iodo(methyl)arsenic(V) hexafluoroarsenates [(CH3)2AsI2]⊕ [AsF6]⊖ (1) and [CH3AsI3]⊕ [AsF6]⊖ (2) have been prepared by direct oxidation of (CH3)2AsI or CH3AsI2 with IF in the presence of AsF5. (CH3)2AsF reacts quantitatively with F2 and AsF5 to yield [(CH3)2AsF2]⊕ [AsF6]⊖ (3). The reaction of 3 with CsF leads to the neutral compound (CH3)2AsF3 (4) and CsAsF6.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 289
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1687-1690 
    ISSN: 0009-2940
    Keywords: Sulfenes ; Thione S,S-dioxides ; Amine adducts ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Reactions of Quinuclidine-Stabilized Sulfenes, R1R2C=SO2←N(CH2CH2)3CHQuinuclidine adducts of the sulfenes 3 and 10 have been isolated and have proven to be good sources for investigating the reactivity of the respective sulfenes. Water and some alcohols react with 3 as well as with “disulfene” (5) in the presence of quinuclidine (2) under formation of the corresponding (alkyl)chinuclidinium methanesulfonyl methanesulfonates 6a-f. The expected intermediate mesyl methanesulfonic acid esters could only be isolated in the case of 4. Similar results were obtained on attempted synthesis of methylsulfene. Only the noncyclic dimer 10 could be prepared, which reacts with alcohols or water forming 11a-c. The formation of “monomeric” sulfene or methylsulfene under these conditions could be ruled out by comparison with their expected hydrolysis products 8 and 13, which were synthesized separately.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 290
    ISSN: 0009-2940
    Keywords: Bicyclo[2.2.1]heptanes ; Tricyclo[5.2.1.02,6]decanes ; Norbornanes ; Ozonization ; Cage compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A four-step preparation of dimethyl 7-oxobicyclo[2.2.1]-heptane-exo-2, exo-3-dicarboxylate (4) in satisfactory yield from the readily available 6,6-dimethylfulvene and maleic anhydride is described. Compound 4 represents a well-functionalized intermediate for the synthesis of norbornane derivatives which is used for an improved synthesis of the tricyclic diester 7, precursor of the cage compound 8. An alternative approach to diester 7 from dimethyl 7-isopropylidenebicyclo[2.2.1]heptane-exo-2, exo-3-dicarboxylate (2) is also discussed.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 291
    ISSN: 0009-2940
    Keywords: Arene complexes / Antimony(III) complexes / Organoantimony compounds / Dihydroanthracene ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Crystals of a 1:2 complex of 9,10-dihydroanthracene and antimony tribromide are obtained from toluene solutions of the components. In the crystal the complex forms corrugated sheets of an inorganic (SbBr3)n coordination polymer, which are cross-linked by antimony coordination to the benzene rings of the dihydroanthracene molecules are also arranged in folded layers. The dihydroanthracene molecules reside on centers of inversion and their carbon skeleton is planar within the limits of the experiment. With contacts from opposite sides of the molecular plane, the dihydroanthracene is η6,(η6)'-coordinated to the Sb(III) centers at distances of 3.25 Å. In a very irregular geometry the coordination sphere of the crystallographically equivalent antimony atoms contains bromine neighbours at different distances. - Antimony trichloride and dihydroanthracene form a complex of ambiguous stoichiometry, while bismuth trichloride again gives a 2;1 complex, the structure of which has not yet been determined.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 292
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 169-176 
    ISSN: 0009-2940
    Keywords: Caesium effect / Chiroptical properties / Circular dichroism / Cyclophanes, multilayered ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chiral Triple-Layered and Condensed [2.2]Cyclophanes - Synthesis, Structure, Chiroptical PropertiesThe helical title compounds 1-5 are obtained using a simple one-step cyclisation reaction with yields reaching or increasing those obtained by application of organometallic methods in [2.2]phane syntheses. The formation of the triple-layered phanes 1 leads with high selectivity only to the “up-down” isomers with fixed conformation, as shown by X-ray crystallography and by the detection of strong NOEs of the inner hydrogen atoms. For studies on structure-chiroptic relation-ships a systematic sequence of helical [2.2]phanes with larger arene systems is synthesized. Enrichment of enantiomers is achieved by HPLC on (+)-PTrMA; the kinetics of racemisation and the CD spectra are discussed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 293
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 201-208 
    ISSN: 0009-2940
    Keywords: Mass Spectrometry / Metal ions, bare / Isocyanides / Bond activation, C-C and C-H / Ion-dipole complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: By screening the reactions of alkyl isocyanides RNC with most of the d-block transition metal ions several trends are uncovered that permit a deeper insight in the intrinsic properties of the metal ions. The ability of C - H activation, relative binding energies to alkenes and hydrogen isocyanide as well reactivity in general can be deduced from collisional activation of RNC/M+ complexes, using tandem mass spectrometry methodologies.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 294
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 75-77 
    ISSN: 0009-2940
    Keywords: Diaminosulfanes / Disilanes / Sulfur diimides ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A New Route to N-Silylated Diaminosulfanes: The Splitting of the Si — Si Bond in Disilanes by Sulfur DiimidesSulfur diimides (R1N)S(N2) (R1, R2 = tBu, SiMe3; 1a-c) and disilanes Cl2(R)Si-Si(R)Cl2 [R = Me (2), Cl (3)] react fast and quantitatively in a 1:1 ratio to give diaminosulfanes (4, 5) by cleavage of the Si-Si bond. The solid-state structure of tBu(SiMeCl2)N-S-N(SiMe3)SiMeCl2 (4b) has been studied both by X-ray crystallography and 29Si-NMR spectroscopy.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 295
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 89-90 
    ISSN: 0009-2940
    Keywords: Dioxasilirane/Silylene oxidation/Matrix isolation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of difluorosilylene and dichlorosilylene with molecular oxygen in Ar matrices has been investigated. Under the reaction conditions the silylenes proved to be of low thermal reactivity, and irradiation in the UV/VIS was necessary to produce difluorodioxasilirane and dichlorodioxasilirane, respectively. The IR spectra have been assigned by isotopic labelling and by comparison with ab initio calculations.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 296
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 115-120 
    ISSN: 0009-2940
    Keywords: Acrylates, 3,3-diazido-2-cyano- / Azirines / Oxazoles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Geminal Vinyl Diazides, IX. - Oxazoles from Methyl 3,3-Diazido-2-cyanoacrylate and AminesReaction of methyl 3,3-diazido-2-cyanoacrylate (1) with amines 2 at - 25°C yields methyl 3-azido-2-cyanoacrylates 3, which on thermal or photochemical treatment give azirines 7 and/or oxazoles 10 (X-ray structure analysis of 101), respectively. On the contrary, 1 reacts at 20°C with amines 13 to form methyl 2-(cyanimino)glycinates 14. Reaction of methyl 3-azido-2-cyanoacrylates 30,1 with triphenylphosphane leads to Staudinger adducts 15, which are transformed by elimination of nitrogen into phosphane imides 16.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 297
    ISSN: 0009-2940
    Keywords: Bond cleavage, C-C, kinetics of / Heats of combustion / Heats of sublimation / Radicals, stability of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermolabile Hydrocarbons, 30. - Thermal Stability and Heat of Formation of 1,1,2,2- and 1.1,1,2-Tetraphenylethane. -Energy of Stabilisation of Benzhydryl and Triphenylmethyl RadicalsHeats of combustion of symmetrical (3) and unsymmetrical tetraphenylethane (4) were determined by combustion calorimetry: ΔHc0(c)(3) = - 3249.5 ± 0.8;(4) = - 3252.0 ± 0.6 kcal/mol. Enthalpies of sublimation of 3 (ΔHsub,298K0 = 32.7 kcal/mol) and 4 (31.7 kcal/mol) were obtained from vapour-pressure-temperature relations, which were determined by a gassaturation method. The resulting heats of formation ΔHf0(g) (3) = 85.4 ± 1.3 and ΔHf0(g)(4) = 87.3 ± 0.8 kcal/mol correspond to low strain energies: H, (3) = 1.5 and Hs (4) = 4.6 kcal/mol. The thermolysis reactions above 200°C in solution with thiophenol as a scavenger are clean first order processes. The following activation parameters are obtained from kinetic measurements: ΔH# (3) = 47.3 ± 0.3, (4) = 45.0 ± 0.3 kcal/mol, ΔS# (3) = 12.8 ± 0.5 and (4) = 14.0 ± 0.6 e.u. From the presented thermodynamic and kinetic data the stabilisation energies of the benzhydryl (1) and the trityl radical (2) have been derived by comparison with the corresponding data for the alkanes 7 and 9. As a result 1 is stabilysed by 12.9 ± 0.9 and 2 by 20.0 ± 1.7 kcal/mol, compared with a secondary or tertiary alkyl radical, respectively. Thus the substituent effect of two (or three) phenyl rings in 1 (or 2) is smaller than twice (or thrice) the value for one phenyl group14): 7.8 ± 2.0 for a secondary and 8.4 ± 1.2 kcal/mol for a teriary benzyl radical. This can be explained by steric repulsion between the phenyl rings and steric inhibition of resonance.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 298
    ISSN: 0009-2940
    Keywords: Ring-chain equilibria of carbanions and radicals / Cyclobutyl anion, stability of / Endocyclic ring opening of cyclobutyl radicals / Ziegler ether cleavage with lithium and sodium / C-C σ-bond cleavage with lithium metal ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Attempted Rearrangement of Cyclobutyl Anions to 3-Butenyl Anions: Endocyclic Ring Opening upon Reaction of 3.3-Diphenyl-1-vinylcyclobutyl Methyl Ether with Alkali Metals - via Anions or Radicals?The reaction of the title compound 16 with lithium or sodium in THF yields mainly the open-chain E/Z isomeric trianions 31 ⇌ 32 besides the expected cyclobutyl anion 10. The endocyclic ring opening takes place via the radical intermediate 28 primarily yielding a butadiene derivative 29, which is then further reduced. The anion 10 - prepared independently by deprotonation of the corresponding hydrocarbon 18 - does not rearrange. On investigating side reactions it was discovered that 4,4-diphenyl-1-butene derivatives treated with lithium in THF undergo C-C bond cleavage affording diphenyl-methyllithium in good yields.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 299
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 300
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 417-422 
    ISSN: 0009-2940
    Keywords: Cobalt(selenoalkyne) complexes / Selenoalkynes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Coordination Ability of Selenoalkynes R - Se - C ≡ C - R′Several synthetic methods for the preparation of selenoalkynes R-Se-C≡C-R′ (1) are discussed. 1 reacts with octacarbonyl dicobalt to yield the η2-π-side-on coordinated alkyne complexes R-Se[(η2-C≡C-R′)Co2(CO)6 (8) which contain a sterically hindered carbon-cobalt tetrahedrane cluster unit. The identity of compounds 1 and 8 is documented by analytical and spectroscopic [IR, MS, 1H-, 77Se-, and 13C-NMR) data as well as by X-ray analysis of C6H5)Co2-(CO)6] (8a).
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...