Iridium complexes [p-Tol4Sb]+[p-Tol4Sb(DMSO)]+[IrBr6]2– and [p-Tol4Sb(DMSO)]+[IrBr4(DMSO)2]–: Synthesis and structure

Abstract

The complex [p-Tol₄Sb]⁺[p-Tol₄Sb(DMSO)]⁺[IrBr₆]^2– (I) has been synthesized by the reaction between tetra(para-tolyl)stibonium bromide and sodium hexabromoiridate(IV) in dimethyl sulfoxide. In a solution, complex I is slowly converted into [p-Tol₄Sb(DMSO)]⁺[IrBr₄(DMSO)₂]^– (II). The antimony atoms in the [p-Tol₄Sb]⁺ cation of complex I have a distorted tetrahedral coordination: СSbС angles are 106.5(3)°–111.1(3)°, and Sb–С bonds range within 2.083(7)–2.097(7) Å. The antimony atoms in [p-Tol₄Sb(DMSO)]⁺ cations have a distorted trigonal bipyramidal coordination to oxygen and carbon atoms in axial positions. The axial OSbC and equatorial СSbC angles are, respectively, 172.5(4)° and 107.6(3)°, 115.9(3)°, 120.0(3)° for I; 177.2(9)° and 113.7(9)°, 116.9(9)°, 117.8(9)° for II. The Sb–C and Sb–O distances are 2.086(7)–2.117(8) and 2.945(9) Å (I), 2.09(2)–2.16(2) and 2.60(2) Å (II). The trans-BrIrBr angles in the octahedral [IrBr₆]^2– and [IrBr₄(DMSO)₂]^– anions range within 178.79(3)°–179.49(3)° and 176.6(4)°–178.79(15)°, respectively. The Ir–Br distances are 2.4686(9)–2.4925(9) Å and 2.463(5)–2.500(4) Å, respectively, and the Ir–S distances are 2.291(7) and 2.340(5) Å.