The “Rh(PPh<sub>3</sub>)<sub>2</sub>” and “Rh(cod)” Fragments as Probes To Compare the Coordinating and Electronic Characteristics of C−SR and C−PPh<sub>2</sub> in Heterodisubstituted Carborane Ligands

Comparison of the coordinating and electronic characteristics of C−SR and C−PPh<sub>2</sub> in [7-PPh<sub>2</sub>-8-SR-7,8-C<sub>2</sub>B<sub>9</sub>H<sub>10</sub>]<sup>-</sup> has been achieved with the fragments “Rh(PPh<sub>3</sub>)<sub>2</sub>” and “Rh(cod)”. The C−SR moiety has a strong polarizing effect on the carborane cage, depleting C−PPh<sub>2</sub> of electronic density and shifting its position in the <sup>31</sup>P NMR downfield as compared to non-thioether-containing complexes. The resolution of the structure of [Rh(7-PPh<sub>2</sub>-8-SR-7,8-C<sub>2</sub>B<sub>9</sub>H<sub>10</sub>)(cod)] has evidenced a stronger σ donation capacity of the C−SR group as compared to the C−PPh<sub>2</sub> group.