Methylenetriimidosulfate H2 CS(NtBu)32- -The First Dianionic Sulfur(VI) Ylide.

Abstract

Through isoelectronic replacement of the oxygen atoms in SO42- ions by one CH2 and three NtBu groups one arrives formally at the dianion H2 CS(NtBu)32- , which has been isolated for the first time in the form of the sulfur(VI) ylide complex [(tmeda)2 Li2 {CH2 S(NtBu)3 }]. Deprotonation of the S-bonded methyl group in the triimidosulfonate MeS(NtBu)3- ion provides facile access in good yields. Hydrolysis favors the formation of the triimidosulfate [{(tmeda)Li2 [OS(NtBu)3 ]}3 ] and methane, and not, as one might expect, diimidomethylenesulfate and the amine. tmeda=Me2 NCH2 CH2 NMe2 .