COPPER(II) AND NICKEL(II) COMPLEXES OF PYRUVALDEHYDE BIS(N(3)-SUBSTITUTED THIOSEMICARBAZONES)

Copper(II) and nickel(II) complexes elf pyruvaldehyde bis{N(3)-methyl- , bis{3)-ethyl-, bis{N(3)-dimethyl- and bis{piperidylthiosemicarbazone } have been prepared and studied spectroscopically. The four thiosemic arbazones have been characterized by their melting points, as well as i.r., electronic and n.m.r. (H-1, C-13) spectra. The four coordinate c opper(II) complexes have been studied by e.s.r. spectroscopy, and the copper(II) and nickel(II) complexes by several of the spectroscopic te chniques mentioned above. Upon formation of these complexes, loss of p rotons from each thiosemicarbazone moiety occurs, and the bis(thiosemi carbazones) coordinate to the metal centres as dianionic, tetradentate N2S2 ligands.