Synthesis and structure of osmium complexes: [Ph3PR]2+[OsBr6]2– (R = cyclo-C3H5, n-C4H9, cyclo-C6H11, CH2C(O)Ph), [Ph3PPr]2+[OsBr6]2– ∙ DMSO, and [Ph3P(CH2)3PPh3]2+[OsBr6]2– ∙ DMSO

Abstract

The complexes [Ph₃PR]₂[OsBr₆], R = cyclo-C₃H₅ (I), n-C₄H₉ (II), cyclo-C₆H₁₁ (III), CH₂C(O)Ph (IV), [Ph₃PPr]₂[OsBr₆] ∙ DMSO (V), and [Ph₃P(CH₂)₃PPh₃][OsBr₆] ∙ DMSO (VI) (CIF files CCDC nos. 1000171, 1000148, 1000172, 1000173, 1000147, and 1000149 for structures I–VI, respectively) were prepared by reactions of sodium hexabromoosmate with phosphonium bromides in dimethyl sulfoxide. According to X-ray diffraction data, phosphorus atoms in the cations have slightly distorted tetrahedral coordination (CPC angles, 105.2(3)°–115.5(3)°; P–C, 1.773(6)–1.814(6) Å). In the octahedral [OsBr₆]^2– anions, the Os–Br bond lengths are 2.4734(8)–2.5203(5) Å and the cis-BrOsBr and trans-BrOsBr angles are 88.38(2)°–91.53(3)° and 177.276(18)°–180°, respectively. The structural organization in the crystals is formed by H∙∙∙Br (2.74–3.04 Å) and H∙∙∙O_DMSO (2.28–2.63 Å) ion–ion hydrogen bonds.