Abstract

Trimesitylgermylcarbodiimide lithium characterized in the reaction of trimesitylgermylchloride on dilithium cyanamide, is the starting material to stable germylsilyl or unsymetric digermylcarbodiimides. The non hindered Ge-N bond of triethylgermylcarbodiimide is cleaved by t-butyllithium providing another route to unsymetric N-triethylgermyl-N'-silylcarbodiimide. Trimesitylgermylcarbodiimide lithium reacts with metal dihalides yielding trimetalled (Ge, Sb) dicarbodiimides. X-ray structure of his (trimesitylgermylcarbodiimido)diethylgermane confirms the inequivalence of the two carbodiimides groups observed by infrared spectroscopy. N-diethylchlorogermyl-N'-trimesitylgermylcarbodiimide with dilithium cyanamide leads to a tetragermyltricarbodiimide : the bis(N-diethylgermyl-N'-trimesitylgermylcarbodiimido)-carbodiimide, in which inequivalence of the ethyl groups can be explained by the steric hindrance of terminal trimesitylgermyl carbodiimido groups.