SYNTHESIS, STRUCTURE, AND ELECTRONIC AND EPR-SPECTRA OF COPPER(II) COMPLEXES CONTAINING THE [CUBR4]2- ANION AND TRIPHENYLARSINE OXIDE

The preparation and characterization of (Ph3AsOH)2[CuBr4] and [Cu(Ph3AsO)4] [CuBr4] are reported (Ph3AsO = triphenylarsine oxide). Crystallographic analysis of the monoclinic crystals of (Ph3AsOH)2[CuBr4] (space group C2/c, a = 17.569 (3) angstrom, b = 13.090 (2) angstrom, c = 16.933 (2) angstrom, and beta = 105.64 (2)-degrees, R = 0.055 and R(W) = 0.057) revealed the presence of compressed [CuBr4]2- tetrahedra of C2 symmetry with Cu-Br distances of 2.340 (1) and 2.437 (1) angstrom and trans-Br-Cu-Br angles of 139.2 (1) and 122.4 (1)-degrees. The oxonium cations hydrogen bond to the bromine atoms involved in the longer Cu-Br bonds and the smaller trans-Br-Cu-Br angle. Single-crystal electronic and EPR spectra are interpreted in terms of the observed [CuBr4]2- geometry. Analysis of the electronic and EPR spectra of [Cu(Ph3AsO)4] [CuBr4] led to the postulation of the presence of planar [Cu(Ph3AsO)4]2+ cations and distorted tetrahedral [CuBr4]2- anions.