Disupersilylmetals (tBu3Si)2M and supersilylmetal halides tBu3SiMX with M = Zn, Cd, Hg: Syntheses, properties, structures [1]

Article abstract of DOI:10.1002/zaac.19976231207

Disupersilylmetals (^tBu₃Si)₂Zn (colorless), (^tBu₃Si)₂Cd (light yellow), (^tBu₃Si)₂Hg (light yellow), and supersilylmetal halides ^tBu₃SiZnCl(THF) (colorless), ^tBu₃SiCdI (colorless), ^tBu₃SiHgCl (colorless) are obtained in THF by the action of ^tBu₃SiNa on ZnCl₂, CdI₂, HgCl₂ in the molar ratio 2:1 and 1:1, respectively. THF can be exchanged by TMEDA under formation of ^tBu₃SiZnCl(TMEDA), and (^tBu₃Si)₂Zn transforms by the action of BiCl₃ or BBr₃ into ^tBu₃SiZnCl (colorless) and ^tBu₃SiZnBr (colorless), respectively. As to X-ray crystal structure analyses, the compounds (^tBu₃Si)₂M are monomeric with a linear SiMSi framework, whereas ^tBu₃SiZnBr and ^tBu₃SiHgCl are tetrameric, the former with a regular, the latter with a pronounced irregular cubic M₄X₄ framework. The compounds are thermal stable up to 200°C (exception (^tBu₃Si)₂Cd), photolabile, and comparatively inert for water and oxygen. The disupersilylmetals work as sources of supersilyl radicals ^tBu₃Si (on irradiation) and as mild supersilanidation agents (e.g. (^tBu₃Si)₂Zn/ BBr₃ → ^tBu₃SiZnBr/^tBu₃SiBBr₂), the supersilylmetal halides as Lewis acids (formation of ^tBu₃SiMX · donor) and electrophiles (e.g. ^tBu₃SiHgCl/RLi → ^tBu₃SiHgR/LiCl).