STUDIES ON SOME TRIVALENT TRANSITION METAL COMPLEXES WITH A BISHYDRAZONE

Complexes of manganese(III), iron(III) and cobalt(III) with a bishydrazone, derived from isatinmonohydrazone and salicylaldehyde, have been synthesized and characterized on the basis of elemental analysis, molar conductance measurements, magnetic susceptibility data, UV-Visible, IR and NMR spectral studies. The spectral data reveal that the ligand acts as monobasic tridentate, coordinating through the phenolate oxygen, azomethine nitrogen, and carbonyl oxygen of the isatin moiety. Analytical data indicate that the complexes possess 1:2 metal–ligand stoichiometry. Molar conductance values adequately support the electrolytic nature of the complexes. On the basis of the above observations the complexes have been formulated as [M(ISA)2]X (where M = Mn^3+, Fe^3+ or Co^3+; X = Cl^-, NO^3- or OAc-; HISA=[2-Hydroxybenzaldehyde-3-isatin]-bishydrazone). Based on electronic spectral data and magnetic susceptibility values, an octahedral geometry has been proposed for the above complexes. The iron(III)complex has been subjected to X-ray diffraction and thermal decomposition studies. The ligand and the metal complexes have been screened for their antibacterial activity and it has been observed that thecomplexes are more potent bactericides than the ligand.