Crystal and molecular structure, magnetic and spectral properties of triaquabis(quinoxaline)copper(II) perchlorate

Abstract The crystal and molecular structure of triaquabis(quinoxaline)copper(II) perchlorate, [Cu(C 8N 2H 6) 2(H 2O 3)](ClO 4) 2, was determined by direct and Fourier methods. The compound crystallized in the monoclinic space group P2 1/c with unit cell parameters a = 8.263(2), b = 17.259(7), c = 15.307(5)A, β = 90.07(2)° and Z = 4. The densities were Dm = 1.763(3) and Dx = 1.76 g cm -3. The molecular structure of the title compound consists of a cation [Cu(C 8N 2H 6) 2(H 2O) 3] 2+, where the copper atom is coordinated to two nitrogen atoms of the quinoxaline molecules and to three oxygen atoms of the water molecules. The coordination polyhedron about the copper atom is a trigonal bipyramid, the oxygen atoms forming the basal plane and the nitrogen atoms occupying the apical positions. The water molecules are involved in hydrogen bonding to perchlorate anions and to two uncoordinated nitrogen atoms of the quinoxaline ligands. The magnetic, infrared and reflectance spectral data are compared with those found for other copper quinoxaline complexes.