Self-assembly of square-planar halide complexes of trimethylphosphine-stabilized diphenyl-arsenium, -stibenium, and -bismuthenium hexafluorophosphates

Square-planar halide complexes in which four trimethylphosphine-stabilized diphenyl-stibenium or -bismuthenium ions surround a central halide ion in discrete centrosymmetrical structures of <i>C</i>_4h symmetry have been isolated and their structures determined by X-ray crystallography. The structures are stabilized by electrostatic interactions between the halide ion and four positively charged trimethylphosphine-stabilized diphenyl-stibenium or -bismuthenium ions, as well as four edge-to-face phenyl–phenyl embraces above and below the plane containing the nine main group elements. The parent halide-free trimethylphosphine-stabilized diphenyl-arsenium, -stibenium, and -bismuthenium hexaflurophosphate complexes have also been prepared and structurally characterized.