Group 4 metallocene complexes of disilenes, digermenes, and a silagermene.

Reactions of 1,2-dipotassiotetrakis(trimethylsilyl)disilane with group 4 metallocene dichlorides lead to the formation of the respective metallocene 1,1,2,2-tetrakis(trimethylsilyl)disilene complexes. While the disilene titanocene complex could be structurally characterized, the zirconocene and hafnocene compounds, which are believed to possess some degree of bis-[bis(trimethylsilyl)silylene] character, can only be isolated in substance as the respective trimethylphosphane adducts. Analogous metallocene 1,1,2,2-tetrakis(trimethylsilyl)digermene complexes and a tetrakis(trimethylsilyl)silagermene complex were prepared. Instead of metallocene 1,1,2,2-tetrakis(trimethylsilyl)distannene complexes, four-membered rings composed of a metallocene and three bis(trimethylsilyl)stannylene units were obtained.