993-62-4Relevant articles and documents
Use of neodymium diiodide in the synthesis of organosilicon, -germanium and -tin compounds
Balashova, Tatyana V.,Kusyaev, Dmitry M.,Kulikova, Tatyana I.,Kuznetsova, Olga N.,Edelmann, Frank T.,Giessmann, Stephan,Blaurock, Steffen,Bochkarev, Mikhail N.
, p. 256 - 260 (2008/10/09)
The reactivity of neodymium diiodide, NdI2 (1), towards organosilicon, -germanium and -tin halides has been investigated. Compound 1 readily reacts with Me3SiCl in DME to give trimethylsilane (6 %), hexamethyldisilane (4 %) and (Mes
ETUDE DE REACTIONS PAR TRANSFERT MONOELECTRONIQUE ENTRE DIVERS HYDROGERMANES A CARACTERE ACIDE ET DES SYSTEMES QUINONIQUES DIA- ET PARA-MAGNETIQUES
Riviere, P.,Castel, A.,Abdennadher, C.
, p. 181 - 194 (2007/10/02)
The chlorogermanes PhnCl3-nGe-H (n = 0, 1, 2) were treated with diamagnetic (3,5-di-t-butylorthoquinone) 1 and the paramagnetic galvinoxyl 2.These reactions occur mainly by monoelectron transfer giving the corresponding adducts.In the case of 3,5-di-t-butylorthoquinone, the resulting 1-4 adducts decompose by two simultaneous processes (HCl elimination and redistribution) yielding germadioxolanes.The chlorogermadioxolanes prepared in this way easily cause halogenic redistribution leading to chlorogermanes and germylcatecholates having branched or spiranestructure.In the case of the galvinoxyl radical, the same chlorogermanes lead by monoelectron transfer to the corresponding quinophenol and an intermediate germanium-centered radical.The latter by recombination outside the solvent cage, gives digermane.However, its primary reaction, which occurs within the solvent cage, is with quinophenol to form two isomeric O- and C-germylated catechols.The C-isomer is by far predominant as it also formed in the secondary hydrogermylation of quinophenol produced in the initial stage of the reaction.We have been able to confirm these mechanisms by a comparative study of the reaction of germanium hydrides R3Ge?+-H?-, acidic germanes X3Ge?--H?+, and germanates X3Ge(-)N-H(+) with galvinoxyl and the corresponding quinophenol.Key words: SET reactions; germylations; quinones; chlorohydrogermanes; chlorogermanes; chlorogermanates.
The effect of substituents on the structure and reactivity of organogermanium anions
Pigarev, S. D.,Bravo-Zhivotovskii, D. A.,Kalikhman, I. D.,Vyazankin, N. S.,Voronkov, M. G.
, p. 29 - 42 (2007/10/02)
The replacement of the ethyl group in Et3GeH by a phenyl group was shown by equilibrium metallation to halve the pKa value compared with analogous CH acids.NMR showed that the decreased acceptor effect of the phenyl group in the PhEt2Ge- anion is caused by a considerably reduced contribution of the mesomeric effect to anion stabilization compared with what happens in the corresponding carbanions.At the same time, the stabilization of the organogermanium anion increases the role of ?-polarization of the aromatic substituent and this contribution is comparable with the mesomeric effect value.A stabilizing effect of organosilicon and organogermanium substituents due to a high degree of polarizability has been shown by concurrent methanolysis of Et3GeLi and REt2GeLi (R=Me3Si, Et3Si, Me3Ge, Et3Ge, t-Bu, Ph).An unexpected reaction of the trimethylsilyl anion with the Me3SiGeEt2- anion leading to diethylgermane dianion, Et2Ge2- has been revealed.The existence of this process supports the suggested absence of (d-p)? interaction in germanium anions with organo-silicon and -germanium substituents.
