Dimeric and polymeric copper(I) complexes. Synthesis and characterization of copper(I) complexes of di-2-pyridyl ketone oxime (DPKox) and crystal structures of [Cu(DPKox)Cl](2)center dot 2H(2)O and [Cu(DPKox)(NCS)](n)

Copper(I) complexes with di-2-pyridylketone oxime (DPKox) of the type CuLX. nH(2)O, n=1 for X=Cl and Br, and n=0 for X=I and SCN, have been synthesized and characterized. The overall physical results suggest tridentate and bid entate DPKox ligand in the Cl, Br and I, SCN complexes, respectively, and t erminal X in the former but bridging X in the later. These complexes displa y MLCT bands in the visible region, but they do not fluoresce at room tempe rature. The structure determination has shown the chloride complex (1) to h ave a centro-symmetrically related dimeric unit, in which each copper atom is coordinated by CI(1), N(1), N(2) and N(3) (of the second ligand molecule ) in a distorted tetrahedral environment. Hydrogen bonds are formed by the O(1) of the oxime group and a lattice water molecule, and between different lattice water molecules and CI(1). The structure of the thiocyanate comple x (2) features tetrahedral geometry around copper atoms, a chelating bident ate DPKox ligand coordinating via one of the two pyridyl nitrogens, N(1), a nd N(oxime) only and mu-1,3-thiocyanate group forming zigzag chains along t he c-axis of the unit cell. (C) 1999 Elsevier Science Ltd. All rights reser ved.