STUDIES ON SOME BIVALENT-METAL COMPLEXES OF SCHIFF-BASES

2-Acetylfuran-2-furoylhydrazone (Haffh), 2-acetylthiophene-2-furoylhydrazone (Hatfh), o-hydroxyacetophenone-2-furoylhydrazone (H2hafh) and 2,6-diacetylpuridine bis(2-furoylhydrazone) (H2dapfh) react with zinc(II), cadmium(II) and mercury(II) chlorides and form the complexes of the types ML2Cl2 [M = Cd(II) and Hg(II), L = Haffh and Hatfh; M = Zn(II), Cd(II) and Hg(II), L = H2hafh], [MLCl]Cl [M = Cd(II) and Hg(II) and L = H2dapfh] and Zn(Hhafh)2. The complexes M(H2acacfh)Cl2 [M = Cd(II) and Hg(II), H2acacfh = acetylacetonebis(2-furoylhydrazone)] were prepared by template reaction. The complexes were characterized by elemental analyses and molar conductance. Infrared spectral studies reveal neutral bidentate bonding of Haffh, Hatfh and H2hafh in the complexes, except Zn(Hhafh)2, in which the Schiff base is bonded in an uninegative tridentate fashion. H2dapfh is a neutral pentadentate ligand while H2acacfh is neutral tetradentate ligand. These observations are also supported by H-1 and C-13 n.m.r. spectral studies. A six-coordinate geometry around the metal ions has been proposed on the basis of these studies.