- Photochemical reactions of aryl-substituted catenates of group 4B elements, PhMe2E-E'Me3 (E, E' = Si and Ge). Formation of a radical pair
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Photochemical reactions of phenyl substituted catenates of group 4B elements, PhMe2E-E'Me3 (E, E' = Si and Ge) have been investigated by chemical trapping experiments and laser flash-photolysis.On irradiation, the phenylated group 4B catenate undergoes E-E' bond homolysis to give a pair of radicals (PhMe2E. and Me3E'.).In CCl4, these radicals are converted to the corresponding chlorides by abstraction of a chlorine atom.In a nonhalogenated solvent, the radical pair couples at the ipso-position of the phenyl group of the pairing radical (PhMe2E.) to yield the cor responding diradical.This undergoes either elimination of a divalent species (Me2E:) with concomitant formation of trimethylphenyl group 4B element PhMe3E') or intramolecular 1,2-group 4B element migration to yield group 4B metal-carbon double bonded species.The radical escapes from the solvent cage coupled to the metal atom of the radical to yield the dimetallic product.The reaction path observed is highly dependent on the nature of the group 4B element comprising the phenyl substituted catenate.
- Mochida, Kunio,Kikkawa, Haruhiko,Nakadaira, Yasuhiro
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- Photochemistry of aryl-substituted trigermanes. Generation and mechanism of formation of germylenes
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Photochemical reactions of aryl-substituted trigermanes have studied by trapping experiments, matrix isolation, and laser flash-photolysis techniques.Photolysis of the phenylated trigermanes involved both the simple extrusion of germylenes and the formati
- Mochida, Kunio,Yoneda, Isao,Wakasa, Masanobu
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- Photochemistry of aryl-substituted trigermanes
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The photolysis of phenyl-substituted trigermanes affords digermanes and germenylenes.Trapping experiments, matrix isolation, and laser-photolysis studies indicate that the photoreaction of these compounds involves both the extrusion of germylenes and the
- Wakasa, Masanobu,Yoneda, Isao,Mochida, Kunio
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- SYNTHESE ET ETUDE SPECTRALE UV DE CHAINES POLYMETALLEES (Ge, Si); ANALYSE THEORIQUE DES EFFETS DE SUBSTITUTION
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An UV study of polymetallic chains of Group IVB elements (Ge, Si) was developed.The studied polygermanes and polygermasilanes were mainly synthetized either by reaction of organolithium with organochlorogermanes or by a Wuetz type reaction.An enhanced λmax value for UV absorption of the chromophore Ge-Ge in these polymetallic compounds is observed in alkyl substitution at the metal by phenyl groups or halogen and also when the polymetallic chain is lengthened.A theoretical approach of these phenomena is proposed based on excitonic coupling between phenyl and metallic chain transition moments.
- Castel, A.,Riviere, P.,Saint-Roch, B.,Satge, J.,Malrieu, J. P.
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p. 149 - 160
(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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