Synthesis, Characterization and Antibacterial Activity of Thorium(IV), Dioxouranium(VI), Cobalt(II), Nickel(II), Copper(II) and Zinc(II) Complexes with Picolinoyl Hydrazones

A series of metal complexes of Th(IV), UO2(II), Co(II), Ni(II), Cu(II) and Zn(II) with 2-acetyl furan picolinoyl hydrazone (AFPH) and 2-thiophen carboxaldehyde picolinoyl hydrazone (TCPH) have been synthesized. The complexes were characterized by elemental analyses (metal and Cl), molar conductance, magnetic susceptibility and spectral (IR, UV-Vis) measurements.
The ligands act as neutral tridentate in metal chloride complexes of the general formula [ML(H2O)Cl2], [L=AFPH, M=Co(II), Ni(II), Cu(II). L = TCPH, M = Co(II), Ni(II), Zn(II)] and [UO2LCl2] (L = AFPH, TCPH) coordinated through carbonyl oxygen, azomethine nitrogen and pyridine nitrogen atoms. The physico_chemical studies suggest octahedral and pentagonal bipyramidal geometries respectively. On the other hand, the ligands act as monobasic tridentate coordinated through the enolic oxygen, the azomethine nitrogen and the pyridine nitrogen atoms in the deprotonated complexes of the types [M(L-H)Cl]2, [L=AFPH, M=Zn(II); L=TCPH, M=Cu(II)], [Th(L-H)2Cl2] (L=AFPH, TCPH), and [M(L-H)2] [L=(AFPH, TCPH), M=Co(II), Ni(II), Cu(II), Zn(II), UO2(II)] forming binuclear square pyramidal and octahedral mononuclear metal complexes. Hexagonal bipyramidal geometry proposed for the dioxouranium(VI) complexes and square antiprismatic or dodecahedral geometries for Th(IV) complexes.