Structural and spectral studies of copper(II) and nickel(II) complexes of pyruvaldehyde mixed bis{N(4)-substituted thiosemicarbazones}

Pyruvaldehyde mixed bis(thiosemicarbazones) have been prepared in which the two thiosemicarbazone moieties have different N(4)-substituents. The mixed bis(thiosemicarbazones) and their copper(II) and nickel(II) complexes have been characterized with IR, electronic, mass, LH NMR (Ni) and EPR (Cu) spe ctra. Representative crystal structures have been solved of nickel(II) comp lexes with either a pyruvaldehyde mixed bis(thiosemicarbazone) or a bis(thi osemicarbazone) with identical N(4)-substituents acting as a tetradentate l igand, [Ni(Pu4M4DE)] has an N(4)-methylthiosemicarbazone substituent on the keto ''arm'' and N(4)-diethylthiosemicarbazone substituent on the aldehyde arm. [Ni(Pu4M)] contains two N(4)-methylthiosemicarbazone moieties. Both b is(thiosemicarbazones) form square-planar N2S2 complexes with nickel(II) an d copper(II). (C) 1999 Elsevier Science Ltd. All rights reserved.