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 C_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.