Osmium complexes [Ph4Sb · DMSO]2[OsBr6] and [p-Tol4Sb · DMSO][p-Tol4Sb][OsBr6]: Synthesis and structure

Abstract

The ionic complexes [Ph₄Sb · DMSO]₂[OsBr₆] (I) and [p-Tol₄Sb · DMSO][p-Tol₄Sb][OsBr₆] (II) have been synthesized by the reaction between sodium hexabromoosmate and tetraphenyl- or tetra-para-tolylstibonium bromide in dimethyl sulfoxide (DMSO). According to X-ray diffraction data, the antimony atoms in [Ph₄Sb · DMSO]⁺ and [p-Tol₄Sb · DMSO]⁺ cations have a distorted trigonal bipyramidal coordination, and the pseudo-axial CSbO and pseudo-equatorial СSbС angles are 173.7(2)°, 172.8(3)° and 111.3(2)°‒121.8(2)°, 107.4(3)°‒120.3(3)°, respectively. In the tetrahedral [p-Tol₄Sb]⁺ cation, the СSbС angles are 106.1(4)°‒111.3(4)°. In the octahedral [OsBr₆]^2‒ anions, the Os‒Br bond lengths are 2.4765(6)‒2.4981(6) Å (I) and 2.4795(11)‒2.5063(11) Å (II); the trans-BrOsBr angles are 180.00(2)° (I) and 178.83(4)°‒179.34(4)° (II).