The Multidentate Ligand (MeOMe₂Si)₃Si⁻: Unusual Coordination Modes in Alkali Metal Silanides

Abstract

Chain gang: Introducing methoxy groups into (Me3Si)4Si and treatment with alkali metal alkoxides leads to hitherto unknown zwitterionic alkali metal silanides [(MeOMe2Si)3SiM] with a bicyclooctane (Li, Na) or heterocubane (K) structure. The lithium and sodium compounds form infinite chains in the solid state (see picture: green Li, blue Si, red O, gray C) and dissociate in THF solutions into zwitterionic monomers.