SYNTHESIS AND CHARACTERIZATION OF METAL COMPLEXES OF TRIDENTATE AND HEXDENTATE HYDRAZONE LIGANDS CONTAINING ANTIPYRINE MOIETY

Abstract

ZrO(II), Zr(IV), Hf(IV), VO(II), La(III) and Sn(II) complexes of H2L ,H2L and H2Lhave been synthesized and characterized by elemental analyses, IR, UV–Vis, conductances, thermal analyses (DTA and TGA). The analyses showed that in all complexes except (5,7, 12, 14) and (19) the ligands behave as monobasic tridentate ligands bonded via the enolic carbonyl oxygen of the hydrazide moiety and coordinated via the azomethine nitrogen and pyrazolone oxygen atoms as in complexes  (3-4, 6, 10-11, 13) and (16, 17, 18, 20 and 21) or neutral tridentate ligands coordinated via the ketonic carbonyl oxygen of thehydrazide moiety, the azomethine nitrogen, pyrazolone oxygen atoms as in complexes (2, 9, 15) and (21). In complexes (5, 12 and 19), the ligands behave as monobasic didentate ligands bonded via the enolic carbonyl oxygen of the hydrazide moiety and coordinated via the pyrazolone oxygen atom.  In case of complexes (7) and (14), the ligands H2L behave as dibasic or neutral hexadentate ligands bonded via the carbonyl oxygen of the hydrazide moiety in enolic or ketonic form, the azomethine nitrogen and pyrazolone oxygen atoms.