SYNTHETIC AND SPECTROSCOPIC STUDIES OF COBALT (II), NICKEL (II), COPPER (II) AND ZINC (II) COMPLEXES OF PYRIDINE-2-CARBOXALDEHYDE THIOBENZOYL HYDRAZONE

Pyridine-2-carboxaldehyde thiobenzoyl hydrazone (2-PTBH) forms 1:1 add ucts with Cu(II) chloride and bromide and 1:2 adducts as well as depro tonated complexes with Cu(II), Ni(II), Co(II) and Zn(II). Magnetic, el ectronic and ESR spectral studies suggest high-spin octahedral geometr y for all the Ni(II) and Co(II) complexes and distorted octahedral geo metry for Cu(II) complexes. The literature survey reveals that no work has been reported on the metal chelates of thiohydrazones derived fro m pyridine-2 carboxaldehyde and thiocarboxyhydrazines except some work published from our laboratory on 3d-metal complexes of pyridine-2, an d 4-carboxaldehyde-2-furanthiocarboxyhydrazones(1). In view of this, t he synthesis and characterization of Co(II), Ni(II), Cu(II) and Zn(I) complexes of the title ligand (2-PTBH, I) have been undertaken and the results of these investigations are described in the present note.