CRYSTAL-STRUCTURE OF THE MACROCYCLIC COMPLEX [CU([16] ANEN4O)] (CLO4)2 ([16]ANEN4O = 1-OXA-4,7,11,14-TETRAAZACYCLOHEXADECANE)

The synthesis and X-ray crystal structure of the Cu(ClO4)2 complex wit h 1-oxa-4,7,11,14-tetraazacyclohexadecane is reported. The macrocyclic cation was found to be disordered over two sites in the asymmetric un it, related by a local mirror plane through the common central metal a tom. The conformation of the complex cation was optimized by molecular mechanics and then used as the trial structure, which was subsequentl y refined as a rigid body. It has approximately square-pyramidal coord ination geometry with oxygen in the basal plane. The apical Cu-N bond length is 2.219 angstrom, compared to the equatorial Cu-N and Cu-O bon ds of 2.040 angstrom (av.) and 2.056 angstrom, respectively. The relat ively high value of the conventional R (= 0.171) is typical for disord ered structures of this type.