EVIDENCE OF SOLVENT COORDINATION IN MIXED-LIGAND COPPER(II) CHELATES - CRYSTAL AND MOLECULAR-STRUCTURE OF AQUO(N,N,N',N'-TETRAMETHYL-1,2-DIAMINOETHANE) (3-CYANO-2,4-PENTANEDIONATO)COPPER(II) PERCHLORATE

The structure of the title compound [Cu(CN-acac)H2O (Me(4)en)]ClO4(C12 H24ClCuN3O7) was determined by X-ray diffraction studies. The structur e is orthorhombic, space group Pbca, Z = 8, a = 10.302 Angstrom, b = 1 5.971 Angstrom, c = 22.945 Angstrom and rho(x) = 1.483 Mgm(-3). The wa ter molecule is covalently bonded to copper. The structure around the central copper atom is distorted square pyramidal with the apex occupi ed by the oxygen atom of the water molecule and the base formed by the oxygen atoms of the beta-dionato (3-cyano-2,4-pentanedionato) moiety and the nitrogen atoms of the N,N,N',N'-tetramethyl-1,2-diaminoethane, Me(4)en. As a result of this coordination a resonance-stabilised, pla nar, six-membered beta-dionato chelate ring and a five-membered chelat e ring with the 1,2-diamine ligand in the gauche conformation are form ed. The perchlorate ion, ClO4- interacts electrostatically with the [C u(CN-acac)H2O(Me(4)en)] entity and forms hydrogen bonds with a hydroge n atom of the water molecule.