- REACTIONS DE DECHLORHYDRATATION D'ORGANOCHLOROHYDROGERMANES ET -POLYGERMANES
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1,8-Diazabicycloundec-7-ene appears to be an efficient dehydrochlorination agent for the organochlorohydrogermanes PhCl2GeH, R2ClGeH (R = Et, Ph).In diluted solutions the intramolecular α-elimination process leads to germylene through germanate
- Riviere, P.,Castel, A.,Guyot, D.,Satge, J.
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p. C15 - C18
(2007/10/02)
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- POLYGERMANES PRECURSEURS D'ESPECES DU GERMANIUM A COORDINNANCE NON USUELLE
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Several thermal or photochemical α-elimination reactions of functional polygermanes lead to germylenes, R2Ge.Photolysis of polygermanes, cyclopolygermanes and polygermylmercury compounds and also hydrogen abstraction from various organohydropolygermanes using t-BuO., lead to the formation of polymetallated chains containing one or two germanium-centered radicals.These polygermyl radicals give germylenes, R2Ge, germanium centered radicals Ge., α-digermyl diradicals (or digermenes) Ge.-Ge. or Ge=Ge> and β- or γ-polygermyl diradicals via ahomolytic monoelectronic α-elimination process.In some cases the formation of α-digermyl diradicals or digermenes can also be seen as occuring through dimerization of germylenes but with lower yields.All these intermediates have been characterized by several trapping reactions with dimethyl disulfide, 2,3-dimethylbutadiene or biacetyl.
- Riviere, P.,Castel, A.,Satge, J.,Guyot, D.
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p. 193 - 206
(2007/10/02)
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- ASSISTANCE NUCLEOPHILE DANS DES REACTIONS D'ORGANO-HALOGENO- ET -HALOGENO-HYDROGERMANES: GERMYLANIONS, GERMYLENES, DERIVES FONCTIONNELS DU GERMANIUM
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Substitution reactions of halogermanes under nucleophilic assistance of tertiary amines or diazo derivatives leading readily to various functional derivatives of germanium have been carried out.Dehydrohalogenation of acidic halohydrogemanes under nucleophilic assistance is a useful way to divalent species, and the germylenes formed are stabilized by complexation with the nucleophilic agent.The reactions proceed via intermediate halogermylanions which lead to the formation of more stable germylenes.The transient halogemylanions have been characterized by means of their nuclophilic additions to carbonyl derivatives.Nucleophilic substitutions of halogermanes using these germylanions lead to the formation of polygermanes.
- Riviere, P.,Castel, A.,Satge, J.
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p. 123 - 136
(2007/10/02)
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- ASSISTANCE NUCLEOPHILE DANS DES REACTIONS DE REDUCTION D'ORGANOHALOGENO- ET HALOGENO-GERMANES PAR DES REDUCTEURS DOUX R3M(IVB)-H ET RCHO: GERMYLANIONS, DERIVES FONCTIONNELS DU GERMANIUM
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Catalytic activity of nuclophiles such as tertiary amines and diazo derivatives in the reduction of halogermanes by means of gentle reductive agents, such as R3M(IVB)-H or RCHO, has been shown.In the particular case of enolisable aldehyde, a competition between nucleophilic substitution at the metal and germanium-halogen bond reduction has been observed.Transposition of enoxygermanes formed through the substitution process, leads to β-germylaldehydes.
- Castel, A.,Riviere, P.,Satge, J.
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p. 137 - 146
(2007/10/02)
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- SYNTHESE DE COMPOSES A LIAISON MIVB-MERCURE. PRECURSEURS D'ESPECES MONOVALENTES (GERMYNES), ET BIVALENTES (GERMYLENES), DE RADICAUX CENTROMETALLES ET D'INTERMEDIAIRES
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Polynuclear germyl-mercury compounds are obtained from the reaction of organohydrogermanes PhnGeH4-n or digermanes Ph2nGe2H4-n (n = 1, 2) with dialkylmercury R2Hg.Di- or tri-mercurated geminal polygermates thus synthesized generally present a low stability and undergo thermal- or photodecompositions leading to the corresponding monovalent (germynes), divalent (germylenes) or, trivalent (germanium centered radicals) species and also to intermediate biradicals which could be considered as limit forms of germanium doubly-bonded compounds .Such intermediates have been chemically and spectroscopically characterized.Extension of these reactions to the silicon analogs met with difficulties, and thus previously observed differences between silicon and germanium chemistry were confirmed.
- Riviere, P.,Castel, A.,Satge, J.
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p. 351 - 367
(2007/10/02)
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