Abstract

Synthesis And Spectroscopic Studies On A Dibasic Pent Dentate Ligand

Author(s): P. Venkateswar Rao, M.Nelamma,B.Krishna Rao,B. Bharath Kumar

The dibasic pentdentate ligand (2,4-dihydroxy-5-acetyl) acetophenone 1Hbenzimidazol- 2yl-hydrazone (H2-DABH) was synthesized by the reaction of 4,6-diacetyl resorcinol with 2-hydrazino benzimidazole in 1:1 molar ratio. The ligand was characterized by elemental analyses, IR, UV-Visible, 1H NMR and mass spectroscopy. Seven transition metal complexes of the pentdentate ligand (H2-DABH) (H2L) with various metal ions such as Cr(III), Fe(III), Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) were synthesized. Elemental analyses, IR, Far IR, UV-visible,ESR,AAS, Thermal analyses, conductance and magnetic susceptibility measurements were used to elucidate the structures of the newly prepared transition metal complexes. From the physico chemical data it was found that the metal to ligand stoichiometry has been found to be 1:1. Divalent metal complexes have the general formula [M(DABH).H2O].,whereas the trivalent metal complexes have it as [M(DABH)⋅Cl]. Infrared spectral data suggest that the ligand behaves as a dibasic pent dentate ligand with O:N:N:O:O donor sequence. On the basis of the analytical data all the complexes have been assigned a polymeric octahedral stereochemistry.