Syntheses and structures of lithium cyanocuprates containing the C(SiMe3)3, C(SiMe3)2(SiMe2NMe2) and C(SiMe3)(SiMe2OMe)2 groups

Abstract

The ‘lower order’ lithium cyanocuprates [Li(thf)2NCCu{C(SiMe3)3}]2 (1d), [Li(thf)2NCCu{C(SiMe3)2(SiMe2NMe2)}]2 (1e) and [Li(thf)NCCu{C(SiMe3)(SiMe2OMe)2}]2 (3) have been obtained from the reactions between copper(I) cyanide and the corresponding organolithium compounds. The compounds 1d and 1e have molecular structures containing four-membered Li2N2 rings but in 3 the lithium is coordinated by the methoxy groups of the ligand and almost linear LiNCCuC sequences are incorporated into fourteen-membered rings. Attempts to make ‘higher order’ cyanocuprates containing tri(organosilyl)methyl groups were unsuccessful and no reactions were observed when the cyanocuprate 1d was treated with alkyl halides or enones.