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.