COORDINATION BEHAVIOR OF THE LIGAND 1,9-BIS(3,5-DIMETHYL-1-PYRAZOLYL)-3,7-DITHIANONANE (BDDN) TOWARDS 1ST-ROW TRANSITION-METALS - X-RAY STRUCTURE OF [CU(BDDN)(H2O)](BF4)2

The synthesis and characterization of the ligand 1,9-bis(3,5-dimethyl-1-pyrazolyl)-3,7-dithianonane (bddn) and its coordination compounds, viz. [M(L)(X)2] where M is Co2+, Zn2+; X is Cl-, Br-, NCS-, and [Cu(L)(H2O)](BF4)2 are described. The X-ray structure of [Cu(bddn) (H2O)](BF4)2 has been determined. The compound crystallizes from ethanol in the monoclinic space group P2(1)/c with unit-cell parameters a = 18.508(5), b = 9.253(3), c = 15.743(5) angstrom, beta = 107.91 (3)-degrees, V = 2565.5 angstrom3, D(calc) = 1.57 g/cm3 for Z = 4. The structure was refined to R = 0.099 and R(w) = 0.116 for 1841 unique reflections with I > sigma-(I). The copper(II) ion is coordinated by two pyrazole nitrogen donors, two thioether donors and a water molecule in a trigonal bipyramidal environment, with the two pyrazoles in an unusual cis position. The donor atoms at the axial positions are a nitrogen and a sulfur, the equatorial plane donors are nitrogen, sulfur and the oxygen atom. From the ligand field spectra, the infrared patterns and the X-ray powder patterns it was concluded that the structures of the cobalt(II)- and zinc(II)-containing compounds are structurally similar to Zn(bddo)(NCS)2, a previously reported chain like structure with an MN2N'2 chromophore, in which the ligand S atoms do not bind to the metal ion.