Synthèses et caractérisation de germylènes difonctionnels

Syntheses and caracterization of bifunctional germylenes Several synthetic methods of bifunctional germylenes GeY 2 (Y = RO, PhO, RS, CH 3 COO, Acac; Y 2 = OCH 2 CH 2 O, SCH 2 CH 2 S) or GeXY (Y = RO, X = Cl; Y = RS, X = Cl; Y = Acac, X = Cl) such as exchange reactions, dechlorhydratation reactions and nucleophilic substitutions from GeCl 2 · dioxane are described. Some more synthesis of divalent species GeY 2 from Ge(OR) 2 by transalcoxylation and from Ge(Cp) 2 by cleavage using protic species will be presented. The stability and reactivity of these germylenes are discussed. Difunctionnal germylenes give generally a selfpolycondensation reactions. However, their reactivity in situ shows a effective participation of monomeric species GeY 2 .