Synthesis and spectroscopic properties of alkali metal derivatives of tris{(diphenylphosphino)dimethylsilyl} methane

Abstract

The organosodium and -potassium derivatives of the type, (Ph₂PMe₂Si)₃CM, (M = Na (2) or K (3)), have been synthesized by the metallation of tris{(diphenylphosphino)-dimethylsilyl}-methane, (Ph₂PMe₂Si)₃CH, I, with MeM (M = Na or K) in THF or Et₂O. Compound 2 has also been synthesized in improved yield from [Li(tmen)₂][C(SiMe₂PPh₂)₃] (1) and NaOBu^t in n-heptane. Compounds 2 and 3 have been characterized by multinuclear NMR studies. These indicate that negative charge associated with the central carbon atom and its attached SiMe₂PPh₂ groups is delocalized over the CSi₃ core of the carbanion.