Synthesis, Molecular Structure, and Reactivity of the Isolable Silylenoid with a Tricoordinate Silicon

The first tricoordinate fluorosilylenoid, (t-Bu2MeSi)2SiFLi·3THF (1), was synthesized, and its X-ray molecular structure was determined. 1 was synthesized in 40% yield by a bromine−lithium exchange reaction in THF of the corresponding fluorobromosilane with t-Bu2MeSiLi. 1 is best described as an R2SiF- anion attracted to a (Li·3THF)+ cation with a small contribution of resonance structure that consists of a silylene fragment and FLi·3THF. 1 reacts as a nucleophile with MeCl, PhH2SiCl, H2O, and MeOH, as an electrophile with MeLi, and as a silylene with Li (or t-BuLi) and Na, yielding α-lithium and α-sodium silyl radicals, respectively. Either photolysis or thermolysis of 1 yields the corresponding disilene R2SiSiR2 (R = t-Bu2MeSi), probably via dimerization of R2Si:.