Synthesis and structure of the rhodium complex [p-Tol4Sb(DMSO-O)]2+[trans-RhBr4(DMSO-S)2]–[cis-RhBr4(DMSO-S)2]–

Abstract

The complex [p-(Tol)₄Sb(DMSO-O)₂⁺[trans-RhBr4(DMSO-S)2]–[cis-RhBr₄(DMSO-S)₂]^– (CIF file CCDC no. 1415243) was synthesized by the reaction of sodium hexabromorhodate with tetra(para-tolyl) stibonium bromide in DMSO and studied by X-ray diffraction. The antimony atoms in two types of crystallographically independent [p-Tol₄Sb(DMSO-O)]⁺ cations have a distorted trigonal-bipyramidal coordination with axially arranged DMSO oxygen atoms (Sb–C, 2.088(9)–2.135(10) Å; Sb∙∙∙O, 2.641(10), 2.690(10) Å). In the octahedral [trans-RhBr₄(DMSO-S)₂]^– and [cis-RhBr₄(DMSO-S)₂]^– anions, the dimethyl sulfoxide ligands are coordinated to the metal via the sulfur atoms. The Rh–S distances are longer in the trans-isomer (2.333(2), 2.339(2) Å) than in the cis-isomer (2.303(3), 2.318(4) Å).