SYNTHESIS AND CHARACTERIZATION OF NICKEL(II), ZINC(II), COPPER(II), COBALT(II) AND COBALT(III) COMPLEXES OF ALPHA-DICARBONYLBIS(AROYLHYDRAZONE)

A variety of alpha-dicarbonylbis(aroylhydrazone) H2L (1) ligands were synthesized and used to synthesize complexes formulated as NiL . nH(2) O, Zn2L2 . nH(2)O, CuL, CoL . nH(2)O and Na[CoL(NO2)(2)], where L refe rs to the dinegative anion of alpha-dicarbonylbis(aroylhydrazone) liga nd. These complexes were investigated by elemental analyses, IR and UV -vis spectra and, for zinc(II), Na[CoL(NO2)(2)] and the anhydrous NiL complexes, H-1 NMR spectra were measured in order to elucidate their s tructures. Other octahedral complexes such as Ni(H2L)(2)(OAc)(2) and C o(HL) . nH(2)O were isolated and characterized. Different modes of coo rdination were assigned to the ligand 1 and its anions in the isolated complexes; dinegative tetradentate, mononegative bidentate and neutra l bidentate. (C) 1997 Elsevier Science Ltd.