Rhodium(I) and rhodium(III) phosphine complexes with nonbridging benzenethiolato ligands: preparation, structures, and chemical properties

Abstract

Reactions of NaSPh with [Rh(PMe[sub 3])[sub 4]]Cl and with RhCl(PMe[sub 3])[sub 3] give Rh(SPh)PMe[sub 3])[sub 3] (1), whose X-ray crystallography shows a square-planar coordination. Temperature-dependent NMR ([sup 1]H and [sup 31]P([sup 1]H)) spectra of 1 show fluxionality of the molecule due to intramolecular exchange of the ligands in the solution. Complex 1 reacts smoothly with air to give the dioxygen-coordinated complex Rh(SPh)(O[sub 2])(PMe[sub 3]0[sub 3] (2). X-ray crystallography shows a distorted trigonal bipyramidal coordination around the metal center having a dioxygen ligand with the O-O bond distance of 1.456(6) [angstrom]. Addition of air to the reaction mixture of [Rh(PMe[sub 3])[sub 4]]Cl with NaSC[sub 6]H[sub 4]-p-OMe gives the analogous dioxygen-coordinated complex Rh(SC[sub 6]H[sub 4]-p-OMe)(O[sub 2](PMe[sub 3])[sub 3] (3). Reaction of complex 1 with HSPh in hexane causes oxidative addition of the S-H bond to the metal center to give the Rh(III) complex cis,mer-RhH(SPh)[sub 2](PMe[sub 3])[sub 3] (4a) as the initial product. Further stirring of the reaction mixture at room temperature causes isomerization of 4a into trans,mer-RhH(SPh)[sub 2](PMe[sub 3])[sub 3] (4b). NMR ([sup 1]H and [sup 31]P) spectra of the complexes 4a and 4b as well as X-ray crystallography of 4b indicate their respective structures unambiguously. Reaction of DSPh (65% D) withmore » 4a gives trans,mer-RhD9SPh)[sub 2](PMe[sub 3])[sub 3] (4b-d[sub 1]) in 55% isotopic purity, while similar reaction with 4b causes deuteration in 18%. Reaction of phenyl acetylene with complex 1 gives mer-RhH-(C[equivalent to]CPh)(SPh)(PMe[sub 3])[sub 3] (5) with the acetylide and the thiolato ligands at mutually trans positions.« less