Copper(II) and nickel(II) complexes of 2,3-butanedione bis(N(3)-substituted thiosemicarbazones)

Copper(II) and nickel(II) complexes of 2,3-butanedione bis(N(3)-methyl-, bis(N(3)-dimethyl-, bis(pyridyl- and bis(hexamethyleneiminylthiosemicarbazone), (H(2)Bu3M, H(2)Bu3DM, H(2)Bupip and H(2)Buhexim, respectively) have been prepared and studied spectroscopically. The four thiosemicarbazones have been characterized by their melting points, as well as IR, electronic and NMR (H-1, C-13) spectra. The four coordinate copper(II) complexes have been studied by EPR spectroscopy and the copper(II) and nickel(II) complexes by a number of the spectroscopic techniques mentioned above. Upon formation of these complexes, loss of the N(2)H hydrogens occurs and the ligands coordinate to the metal centers as dianionic, tetradentate N2S2 ligands. The crystal structures of H(2)Bupip and the nickel(II) complex of 2,3-butanedione N3-methylphenylthiosemicarbazone, [Ni(Bu3MPh)], have been solved. (C) 1997 Elsevier Science Ltd.