Dicationic sulfur analogues of N-heterocyclic silylenes and phosphenium cations.

DABling with sulfur: Sulfur(II) dications can be prepared using alpha-diimines to stabilize the positive charge (see scheme; DAB = diazabutadiene, Dipp = 2,6-diisopropylphenyl, OTf = CF(3)SO(3)). The bonding is best described as that of a N,N-chelated sulfur(II) dication; these species represent the first sulfur-based structural mimics of N-heterocyclic silylene compounds and phosphenium cations.