The “Rh(PPh3)2” and “Rh(cod)” Fragments as Probes To Compare the Coordinating and Electronic Characteristics of C−SR and C−PPh2 in Heterodisubstituted Carborane Ligands

Comparison of the coordinating and electronic characteristics of C−SR and C−PPh2 in [7-PPh2-8-SR-7,8-C2B9H10]- has been achieved with the fragments “Rh(PPh3)2” and “Rh(cod)”. The C−SR moiety has a strong polarizing effect on the carborane cage, depleting C−PPh2 of electronic density and shifting its position in the 31P NMR downfield as compared to non-thioether-containing complexes. The resolution of the structure of [Rh(7-PPh2-8-SR-7,8-C2B9H10)(cod)] has evidenced a stronger σ donation capacity of the C−SR group as compared to the C−PPh2 group.