Oxidative Addition of the C−S Bond of Thiophene to the (C₅Me₅)Rh(PMe₃) Fragment: A Theoretical Study Revisited

Density functional theory (DFT) calculations on the C−S bond activation reaction of thiophene with the [(C₅Me₅)Rh(PMe₃)] fragment have been reinvestigated, giving two new isomeric C−S bond activation transition states, in which the coordinated thiophene molecule tilts toward either the C₅Me₅ ligand or the PMe₃ ligand. Through intrinsic reaction coordinate (IRC) calculations, these transition states were found to connect the oxidative addition product with two isomeric η²-C,S coordinated intermediates. These latter intermediates in turn connected to two isomeric η¹-S and η²-C,C coordinated species. The energetics and mechanistic details are described.