Tris(triorganosilyl)methyl derivatives of potassium and lithium bearing dimethylamino or methoxy substituents at silicon. Crystal structures of KC(SiMe_3)_2(SiMe_2NMe_2), KC(SiMe_2NMe_2)_3 and (LiC(SiMe_3)(SiMe_2OMe)_2)_2

摘要

The compounds HC(SiMe_3)(SiMe_2X)_2, X = NMe_2 or OMe, have been synthesized in several steps from the phenyl derivative HC(SiMe_3)(SiMe_2Ph)_2 and metallated to give organometallic compounds of the type MC(SiMe_3)(SiMe_2X)_2, M = K or Li. The structures of the compounds KC(SiMe_3)_2(SiMe_2NMe_2) and KC(SiMe_2NMe_2)_3 consist of infinite chains in which cations are co-ordinated to both nitrogen and carbon centres, whereas the lithium compound [LiC(SiMe_3)(SiMe_2OMe)_2]_2 crystallises in a lattice of dimeric cage molecules. Structural trends in the series MC(SiMe_3)_n(SiMe_2X)_(3-n), n = 0-3, M = K or Li, X = NMe_2 or OMe, are discussed.