Conversion of Dithiocarbamate Ligand into Sulphate Anion : Spectroscopy, X-ray Crystallography and Valence Bond Sum (VBS) Based Investigations

Copper(II)dithiocarbamate complexes,[Cu(dtc)2], (dtc = N-methyl, Nethanoldithio-carbamate, diethanoldithiocarbamte, piperidinedithiocarbamate, piperazinedithiocarbamate, morphlinedithiocarbamate, diisopropyldithiocarbamate, diethyldithiocarbamate, dimethyldithiocarbamate) were treated with 2,2’-bipyridine in ethanol or ethanol/chloroform medium under refluxing conditions. The products were analyzed by IR and UV-Visible spectra, electrical conductivity, elemental analysis and single crystal X-ray crystallography. Characterization studies showed that the product, [Cu(2,2’-bipy)(H2O)2]SO4, is identical in all the reactions. Dithiocarbamate ligand of each copper complex oxidized to SO4 ion. Single crystal X-ray structure of [Cu(2,2’-bipy)(H2O)2]SO4 indicate that the central copper atom is in a distorted octahedral environment. Valence Bond Sum (VBS) value was also calculated for the crystal structure of [Cu(2,2’-bipy)(H2O)2]SO4 and the results are reported in this paper. The VBS value was found to be equivalent to 1.96, supporting the correctness of the determined crystal structure and the value is close to +2, which is the formal oxidation state of copper.