Synthesis and spectral characterization of metal complexes containing tetra- and pentadentate Schiff base ligands

Two new Shiff base ligands, N,N' -bis[2-hydroxy-3 -methoxy-N-(p-methyl phen ylene)benzylamine]-2,6-diacetylpyridinimine (H2L1), N,N'-bis[2-hydroxy-3-me thoxy-N-(p-methylphenylene)benzylamine]phtaldialdimine (H2L2) and their Cu( II), Co(III), Ni(II), Pd(II), VO(IV) and Zn(II) metal complexes have been p repared and characterized by elemental analyses, FT-IR, electronic spectra, magnetic moments, H-1 and C-13 NMR spectra, mass spectral and molar conduc tance data. The mononuclear Co(III) complexes of these ligands have diamagn etic character and octahedral geometry around the metal ion. The ketoimine- enolimine equilibria of the ligands were investigated by electronic spectra and showed that the ligands preferred the ketoimine form in nonpolar solve nts. It has been found that the ligands and their complexes are non-electro lytic in nature. Spectral measurements showed that the ligands were coordin ated to the metal ion through the azomethine nitrogen and phenolic oxygen a toms. The TG and DTA properties of the compounds have been studied.