- Syntheses de 3-silyl et de 3-germyl 1-sila et 1-germacyclopent-3-enes
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The synthesis of allylic sila (and germa) cyclopentenes containing an Et3M (M=Si, Ge) group in vinylic position is described. 1-Germacyclopent-3-enes 3-silylated (IIIa) and 3-germylated (IIIb) result from 1,4-cycloaddition of GeI2 to the corresponding 2-m
- Boukherroub, Rabah,Manuel, Georges
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- Selective reduction of a C–Cl bond in halomethanes with Et3GeH at nanoscopic Lewis acidic Aluminium fluoride
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The selective activation of C–Cl bonds of hydrochlorofluoromethanes and chloromethanes at moderate reaction conditions using ACF in a combination with Et3GeH is presented. The reactions of the chloromethanes (CH3Cl, CH2Cl2, CHCl3 and CCl4) in the presence of Et3GeH and ACF as catalyst led to the activation of only one C–Cl bond resulting in the hydrodechlorination. Friedel-Crafts reactions with benzene as solvent are suppressed by Et3GeH. A selective hydrodechlorination of hydrochlorofluoromethanes was achieved, because a transformation of a C–F bond into a C–H bond by the combination of ACF with Et3GeH did not occur. Supporting PulseTA experiments illustrated the interaction between the solid catalyst and Et3GeH, the solvent benzene or CH2Cl2.
- Mei?ner, Gisa,Feist, Michael,Braun, Thomas,Kemnitz, Erhard
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p. 234 - 241
(2017/09/12)
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- Reaction of organoelement hydrides R3EH (E = Si, Ge) with metal tert-butylate (M = Al, Ti)-tert-butyl hydroperoxide oxidative systems
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Trialkyl(aryl)silanes and -germanes effectively react with metal (Al, Ti) tert-butylate-tert-butyl-hydroperoxide under mild conditions (room temperature, benzene or tetrachloromethane) mainly by the element-hydrogen bond. The character of the products depends on the nature of the element, the structure of the radical bound to it, and the solvent. The process is radical in nature. It includes the stages of formation of element-centered radicals and their reaction with the oxygen generated by the system. The intermediate organometallic peroxides can also acts as oxidants for the element (Si, Ge)-hydrogen bonds. 2005 Pleiades Publishing, Inc.
- Stepovik,Gulenova,Martynova,Skvortsov,Cherkasov
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p. 1098 - 1107
(2007/10/03)
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- New stable germylenes, stannylenes, and related compounds. 1. Stable germanium(II) and tin(II) compounds M(OCH2CH2NMe2)2 (M = Ge, Sn) with intramolecular coordination metal-nitrogen bonds. Synthesis and structure
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New stable monomeric germanium(II) and tin(II) compounds M(OCH2CH2NMe2)2 (M = Ge (1); M = Sn(2)), stabilized by two intramolecular coordination M←N bonds and containing no bulky groups on the metal atoms, were synthesized. The molecular and crystal structures of these compounds, and that of the previously synthesized compound (ArO)2Sn (3; Ar = 2,4,6-(Me2NCH2)3C6H2), were determined by X-ray diffraction analysis. The electronic structures of 1 and 2 were studied by the DFT method.
- Zemlyansky, Nikolay N.,Borisova, Irina V.,Kuznetsova, Marianna G.,Khrustalev, Victor N.,Ustynyuk, Yuri A.,Nechaev, Mikhael S.,Lunin, Valery V.,Barrau, Jacques,Rima, Ghassoub
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p. 1675 - 1681
(2008/10/08)
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- Redox reactions of GeII and SnII dihalides with triethylsilane and triethylgermane
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Dihalogermylenes, dihalostannylenes, and their complexes (EI2, ECl2?dioxane, and (CO)5W=ECl2?THF, where E = Ge or Sn), unlike organylgermylenes, are not inserted at the Si-H (Ge-H) bond of triethylsilane (triethylgermane). The reactions of SnI 2, ECl2?dioxane, and (CO)5W=ECl 2?THF (E = Ge or Sn) with Et3E′H (E′ = Si or Ge) occur as redox processes. Depending on the nature of the reagents, the reactions afford products of oxidative coupling (Et3SiSiEt 3) and/or haloiodination (Et3SiX and Et3GeX) of triethylsilane (triethylgermane). The proposed mechanism of these reactions involves the electron transfer to form radical-ion pairs.
- Nosov,Koroteev,Egorov
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p. 1325 - 1328
(2007/10/03)
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- Selective synthesis of chlorohydrogermanes from mono-, di-, and trihydrogermanes
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Treatment of hydrogermanes, R4-nGeHn (R = Hex, Et, Ph, n = 1-3), with 2 equiv of CuCl2 in ether at room temperature or in toluene under reflux led to selective replacement of an H-Ge bond with a Cl-Ge bond, giving the corresponding chlorohydrogermanes, R4-nGeHn-1Cl, selectively.
- Ohshita, Joji,Toyoshima, Yutaka,Iwata, Arihiro,Tang, Heqing,Kunai, Atsutaka
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p. 886 - 887
(2007/10/03)
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- Synthesis and structure of oligomeric dimesitylgermyl-substituted carbodiimides; characterization of higher oligomers
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New cyclic oligomers of dimesitylgermylene carbodiimides (Mes2GeNCN)n (n = 3 (1) and 4 (2)) were synthesized by reactions of dimesityldichlorogermane with either cyanamide in the presence of triethylamine or lithium cyanamide. The re
- Dahrouch, Mohamed,Rivière-Baudet, Monique,Satgé, Jacques,Mauzac, Monique,Cardin, Christine J.,Thorpe, James H.
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p. 623 - 629
(2008/10/08)
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N-Trialkylgermyl or triarylgermyl derivatives of sulfamids were obtained by transmetallation from lithium sulfamids, through intermolecular dehydrohalogenation between sulfamids and trialkyl-or triarylgermyl- chlorides or by transamination. For the transamination from N-dialkylgermylamines by sulfamids, it was established that the reactions do not depend only on the acidity of the protons of the sulfamids, but equally on the nucleophily of the nitrogen atom bearing these protons. With sulfamid itself, only symetrical di- or tetra-germylated compounds were formed. With sulfanilamid, monometallation can be obtained and occurs on the more nucleophilic nitrogen, neighbouring the SO2 group. Polymetallated compounds such as tetra(triethylgermyl)sulfanilamid are obtained by transmetallation. However steric hindrance plays a prominent role and trimesitylgermylderivatives were never obtained. The Ge-N bond in germylsulfamids is easily cleaved by protic species.
- El Baz, Fatima,Ahra, Mohamed,Riviere-Baudet, Monique
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- Organogermanium dendrimers
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The first organogermanium dendrimers were synthesized by using divergent and convergent routes. The principal reactions used for these syntheses are hydrogermylation or hydrozirconation-transmetalation. These dendrimers were characterized by their IR, su
- Huc, Vincent,Boussaguet, Paul,Mazerolles, Pierre
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p. 253 - 260
(2007/10/03)
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- Investigation of the reaction of bis(triethylgermyl)cadmium with titanium tetrachloride
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The reaction between (Et3Ge)2Cd and TiCl4 in the presence of α,α'-bipyridyl afforded a compound with a Ge-Cd-Ti group.This compound was characterized by IR and ESR spectroscopy.Thermal decomposition of this compound at 130 and 160 deg C and its interaction with gaseous HCl were studied.A novel complex, (Et3Ge)2Cd*bpy, was obtained as a by-product of the reaction, and some its physicochemical characteristics were determined.Based on the experimental results, a scheme for the interaction of (Et3Ge)2Cd with TiCl4 has been suggested. - Key words: mixed organo-Cd, Ti compounds.
- Lomakova, I.V.,Patrikeeva, N. B.,Domrachev, G. A.,Petrov, B. I.
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p. 1242 - 1244
(2007/10/02)
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- ABOUT THE MECHANISM OF THE PHOTOLYSIS OF BENZOYLTRIETHYLGERMANE, Et3GeCOPh
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The detailed mechanism of the photolysis of benzoyltriethylgerman Et3GeCOPh in various media has been studied using the chemically induced dynamic nuclear polarization method (1 H CIDNP).It has been shown that in all cases the photolytic decomposition lea
- Taraban, M. B.,Maryasova, V. I.,Leshina, T. V.,Rybin, L. I.,Gendin, D. V.,Vyazankin, N. S.
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p. 347 - 356
(2007/10/02)
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- Cycloaddition of Germylenes to 3,5-Di-t-butylorthoquinone
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The germylenes X2Ge, RGeX and R2Ge (X= halogen, OR; R= alkyl or aryl) react at room temperature with 3,5-di-t-butyl orthoquinone by regioselective cycloaddition.The corresponding substituted 2-germa-1,3-dioxolans are formed similarly in good yields, but t
- Riviere, Pierre,Castel, Annie,Satge, Jacques,Guyot, Daniel
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p. 157 - 164
(2007/10/02)
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- Anchimeric Assistance in C-H Bond Homolysis. Reaction of tert-Butoxyl Radicals with Tetraethyl Group 4 Compounds
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Three complementary techniques have been used to obtain relative and absolute rate constants for the abstraction of α- and β-hydrogen atoms from (CH3CH2)4M (M=C, Si, Ge, Sn) by tert-butoxyl radicals.Both α and β positions of Et4M are activated for M=Si, Ge, Sn, as compared with the 1- and 2-positions in n-pentane.The activation was greater at the β than at the α position, and followed the order Sn>Ge>Si.This provides unequivocal evidence for anchimeric assistance to removal of hydrogen β to a Si, Ge, or Sn atom.
- Jackson, Richard A.,Ingold, Keith U.,Griller, David,Nazran, Avtar S.
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p. 208 - 211
(2007/10/02)
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- Photoinduced reactions of organic compounds with transition metal complexes. III. Formation of a σ-methyl complex of platinum(IV) and a π-ethylene complex of...
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Title full: Photoinduced reactions of organic compounds with transition metal complexes. III. Formation of a σ-methyl complex of platinum(IV) and a π-ethylene complex of platinum(II) in photochemical and thermal reactions of PtCl62- with methyl and ethyl derivatives of tin or germanium. thermal oxidative addition of Me4Sn to PtCl42- to afford the σ-methyl complex of platinum(IV). The photoinduced reaction of PtCl62- with alkyl derivatives of tin or germanium in acetic acid or acetone is described. The reaction with (CH3)4Sn affords the complex Ch3PtCl52- (I) whereas irradiation of PtCl62- with (CH3)2Sn(C2H5)2 leads to the formation of I and [(CH2CH2)PtCl2]2 (III). Complex III is formed in the reaction with Ge(C2H5)4. The proposed mechanism of electrophilic substitution by the platinum(IV) complex involves electron transfer from the tetraalkylmetal to the platinum(IV) complex and is labelled the SE1e.t. mechanism. The platinum(II)-ethylene complex III appears to be formed from CH3CH2PtCl52- (II) upon light irradiation via β-hydrogen elimination. The thermal reaction of PtCl62- with (CH3)4Sn to afford complex I is catalysed by PtCl42-. The thermal reaction of (CH3)4Sn with PtCl42- in acetic acid or aqueous acetone affords the σ-methyl complex of platinum(IV).
- Shul'pin,Nizova,Kitaigorodskii,Serdobov
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p. 273 - 282
(2007/10/02)
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- REACTIONS OF TRIETHYLGERMYLLITHIUM WITH N,N-DIALKYLATED CARBOXAMIDES
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The reactions of triethylgermyllithium with N,N-dialkylated carboxamides have been investigated.N,N-Dimethylacetamide, N,N-dimethylpivalamide, N,N-diethyltrifluoroacetamide and N,N-diethylbenzamide act on triethylgermyllithium, which is made from bis(triethylgermyl)mercury and lithium in hexane, to release the corresponding acyltriethylgermanes as the principal product.The regioselectivity of the present reactions was found to depend markedly on the reaction conditions and the nature of the acyl fragment of amides.Thus, triethylgermyllithium reacts with N,N-dimethylacetamide as metallating agent to give lithium N,N-dimethylacetamide, if the reaction is carried out in tetrahydrofuran solution.Mechanistic interpretations of these results are discussed.
- Bravo-Zhivotovskii, D. A.,Pigarev, S. D.,Kalikhman, I. D.,Vyazankina, O. A.,Vyazankin, N. S.
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- INSERTION REACTIONS OF ELECTRON-DEFICIENT SPECIES: INSERTION OF GERMYLENES AND PHENYLPHOSPHINIDENE INTO GERMANIUM-GERMANIUM BONDS
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The reactions of germylenes with pentafluorophenyl- and alkylpentafluorophenyl-digermanes give the trigermanes (X=F, Cl; Y=F, Ph; R=C6F5, Et).Their thermal decomposition involves α-elimination to give halogermanes and germylgermylenes.These last
- Castel, A.,Escudie, J.,Riviere, P.,Satge, J.,Bochkarev, M.N.,Et Al.
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- METAL-HALOGEN BONDING STUDIES WITH GROUP IV A TRIALKYLMETAL HALIDES
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Halogen redistribution reactions have been found to take place between benzyl bromide or benzyl iodide and the Group IV A silicon, germanium, tin, and lead containing trialkylmetal chlorides.However, for the reactions of the Si, Ge and Sn compounds, a quaternary ammonium halide catalyst was necessary to enable the equilibria to be established at reasonably rapid rates.The equilibrium constants at 50 deg C have been measured for each of these halogen redistributions.They have been found to increase gradually on going down in Group IV A from silicon to lead, being conside rably less than unity in the case of silicon and somewhat greater than unity in the case of lead for both the R3MCl + BzBr and R3MCl + BzI reactions.The ΔG0 values for these equilibria have been calculated, and it is suggested that their differences may be explained in terms of the relative importance of p?-d? contributions to the halogen-metal bonding in the various Group IV A trialkylmetal halide systems.
- Friedrich, Edwin C.,Abma, Charles B.,Vartanian, Paul F.
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p. 203 - 212
(2007/10/02)
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