Bismuth(III) Complex of the [S4]•– Radical Anion: Dimer Formation via Pancake Bonds

Reaction of bismuth­(II) compounds with sulfur gives mixtures of [Bi­(NONR)]2(μ2-Sn) (NONR = [O­(SiMe2NR)2]2–). Examples for n = 1 and 3 have been crystallographically verified for R = 2,6-iPr2C6H3 (Dipp) and R = tBu, and the pentasulfide (n = 5) for R = Dipp. The corresponding product from reaction with the new Bi­(II) radical Bi­(NONAr‡)• (Ar‡ = C6H2(CHPh2)2-tBu-2,6,4) exists as the dimer [Bi­(NONAr‡)­(S4)]2, with π*­(SOMO)−π*­(SOMO) interactions linking the sulfur chains through trans-antarafacial pancake bonds.