Synthesis and Structure of Bismuth Complexes [Ph3(n-Pr)P]2+[Bi2I8•2Me2S=O]2-, [Ph3(iso-Bu)P]2+[Bi2I8•2Me2S=O]2-, [Ph3(n-Bu)P]2+[Bi2I8•2Me2S=O]2-, and [Ph3(n-Am)P]2+[Bi2I8•2Me2S=O]2-

The complexes [Ph-3(n-Pr)P](2)(+)[Bi2I8 center dot 2Me(2)S=O](2-) (I), [Ph-3(iso-Bu)P](2)(+) [Bi2I8 center dot 2Me(2)S=O](2-) (II), [Ph-3(n-Bu)P](2)(+)[Bi2I8 center dot 2Me(2)S=O](2-) (III), and [Ph-3(n-Am)P](2)(+) [Bi2I8 center dot 2Me(2)S=O](2-) (IV) are synthesized by reactions of triphenylalkylphosphonium iodide with bismuth iodide in dimethyl sulfoxide. In all complexes, the P atoms in cations have a distorted tetrahedral coordination (the CPC angles vary from 106.4(8)degrees to 114.8(2)degrees). In the dihedral centrosymmetric anions, the octahedral bismuth atoms are bound to each other by two bridging (br) iodine atoms (Bi-I-br 3.167(1), 3.273(1) angstrom (I); 3.1557(2), 3.2589(2) angstrom (II); 3.1961(3), 3.3108(3) angstrom (III); 3.1913(4), 3.3161(4) angstrom (IV)), which are coplanar to four terminal (t) iodine atoms (Bi-I-t 2.956(1), 2.989(1) angstrom (I); 2.9557(2), 2.9872(2) angstrom (II); 2.9206(3), 2.9706(3) angstrom (III); 2.9328(4), 2.9890(4) angstrom (IV)). Two remaining positions at the bismuth atoms are occupied by the iodine atom (Bi-I 2.987(1) angstrom (I); 3.0051(2) angstrom (II); 2.8984(3) angstrom (III); 2.9046(4) angstrom (IV)) and the dimethyl sulfoxide molecule (Bi-O 2.458(12) angstrom (I); 2.430(2) angstrom (II); 2.507(3) angstrom (III); 2.544(4) angstrom (IV)).