Crystal structure of 1,4,8,12-tetraazacyclopentadecane copper(II) tribromocuprate(I)

The title compound is a mixed valence compound obtained as one of the products of the reaction of Cu(15-ane N-4)Br-2 with CoBr2 . 6H(2)O in water/acetone solvent (15-ane N-4 = 1,4,8,12-tetraazacyclopentadecane). The compound is tetragonal, space group P4(2)/mbc with a 16.675(2)Angstrom, c = 13.185(3)Angstrom, V = 3666(1)Angstrom(3), with Z = 8, for rho(calc) = 2.106 g/cc. Refinement of 674 unique observed reflection yielded final values of R = 0.088 and R(w) = 0.083. The compound contains chains of alternating Cu(15-ane N-4)(2+) cations and CuBr32- anions. The chains run perpendicular to the c axis, and are arranged in alternate layers running parallel to a and b. The chains lie athwart the mirror planes at z = 0 and z = 1/2, with disorder observed for both the (15-ane N-4) rings and the CuBr32- anions. The Cu(Il) ion is coordinated by the tetradentate macrocycle to yield an approximate square planar coordination. The CuBr32- anions are nearly planar with Cu-Br(ave.) = 2.37 Angstrom. Long semi-coordinate Cu(II)... Br bonds of similar to 3.0 Angstrom link the cations and anions.