Thiaplatinacycles derived from dibenzothiophene-containing phosphites as auxiliary ligands and their role in homogeneous desulfurization reactions

The reaction of complex [Pt(eta(2)-C, S-C12H8)(PEt3)(2)], 1, with a variety of phosphites afforded compounds of the type [Pt(eta(2)-C, S-C12H8)(PEt3)(P(OR)(3))], where R = Et, Pr-i, and Ph (2a, 2b, 3, and 4, respectively) and [Pt(eta(2)-C, S-C12H8)(P(OR)(3))(2)], where R = Et (5). Compounds 2-4 were used to model a desulfurization process and were compared with 1 and other similar compounds. Under comparable conditions, the amount of desulfurization depended on the sigma-donor/pi-acceptor properties and the steric effects of the ligands and of the use of alumina in the reaction media. X-ray crystal structures are reported for 2b and 3.