Structural properties and inversion mechanisms of [Rh(dippe)(μ-SR)]2 complexes

Several new bis-thiolate complexes of the type [Rh(dippe)(μ-SR)]2 where R=H, methyl, cyclohexyl, o-biphenyl, and phenyl, or (SR)2SCH2CH2CH2S have been synthesized and characterized by NMR spectroscopy and single crystal X-ray diffraction. All [Rh(dippe)(μ-SR)]2 complexes except [Rh(dippe)(μ-SPh)]2 exhibit bent geometries, while the orientation of the thiolato substituents changes with increasing steric bulk. 1H and 31P NMR spectroscopies indicate that both ring inversion and sulfur inversion occur among the members of the series, which allows them to access several isomeric forms when they are in solution. 31P NMR spectroscopy indicates that sulfur inversion in [Rh(dippe)(μ-SH)]2, [Rh(dippe)(μ-Sbiphenyl)]2, and [Rh(dippe)(μ-SPh)]2 is a non-dissociative process.