Bis(trimesitylgermylcarbodiimido)germylene, trimesitylgermylcyanamide and trimesitylgermylcarbodiimide

Bis(trimesitylgermylcarbodiimido)germylene (1), isolated as a white precipitate from the reaction of lithium trimesitylgermylcyanamide with dichlorogermylene, is stable at room temperature in the absence of water and oxygen. The germylene structure is preserved in the reaction with 3,5-di-t-butylcatechol, while subsequent addition to 3,5-di-t-butylorthoquinone gave the corresponding spirogermane. Thermal decomposition of 1 occurs around 50°C leading to bis(trimesitylgermyl)carbodiimide and polycarbodiimidogermylene. Hydrolysis of 1 gave the corresponding monogermylated derivative of cyanamide (3) in two isomeric forms: trimesitylgermylcyanamide (3a) and trimesitylgermylcarbodimide (3b), in equilibrium in solution. Isomer 3b is the first compound to precipitate from a benzene solution. Its structure was established by X-ray diffraction. Compound 3 decomposes on heating to form dicyanamide and bis(trimesitylgermyl)carbodiimide.