Synthesis and NMR-study of the 2,3,4,5-tetraethylsilole dianion [SiC 4Et 4] 2-•2[Li] +

Abstract

The previously unknown silole dianion [SiC 4Et 4] 2-•2[Li] + (3) was prepared by the sonication of 1,1-dichloro-2,3,4,5-tetraethyl-1-silacyclopentadiene [Cl 2SiC 4Et 4, 2] with more than four equivalent of lithium in THF. 1H-, 13C-, and 29Si-NMR data of 3 are compared with those of the reported silole dianion [SiC 4Ph 4] 2-. Trapping of 3 with trimethylchlorosilane gave 1,1-bis(trimethylsilyl)-2,3,4,5-tetraethyl-1-silacyclopentadiene [(Me 3Si) 2SiC 4Et 4, 4] in high yield. The silole of 2 was synthesized in high yield in three steps by a modified procedure using Cp 2ZrCl 2 via Cp 2ZrC 4Et 4 and 1,4-dibromo-1,2,3,4-tetraethyl-1,3-butadiene. © 2011 by The Authors.