Crystal and molecular structure of a solvate of chloro-[1,6-bis-(2′-pyridyl)-2,5-diazahexane]copper(II) chloride

Abstract

The structure of the α-form of the title compound has been determined by a three-dimensional X-ray structural analysis. Crystals are monoclinic with a= 9·73(1), b= 13·66(1). c= 14·52(1)Å, β= 112·95(5)°, space group P2₁/c, and Z= 4. The structure was solved by conventional Patterson and Fourier techniques and refined by block-diagonal least-squares methods to a final R of 0·102, for 1246 independent reflections collected on an automatic diffractometer. The cation is five-co-ordinate with a geometry approximating to a square pyramid. One of the pyridyl nitrogens occupies the axial position with Cu–N 2·21 (2)Å. The other bond lengths are normal, although there are distortions of the co-ordination polyhedron resulting from ligand constraints, and some distortions of bond angles in the chelating ligand itself. The chloride anions form hydrogen-bonded ‘bridges’ between secondary amine nitrogens of screw-related cations. The solvent (water or methanol) is disordered in regions around centres of symmetry; water and/or methanol can be accommodated with small variations of the unit-cell dimensions.