Stability and structure of sollle metal complexes involving tri- and tetra-dentate Schiff bases

Department of Chemistry, Manonmaniam Sundaranar University, Tirunelveli-627 012, Tamilnadu, India E-mail: msnairchem@rediffmail.com Manuscript received 17 March 2006, revised 5 June 2006, accepted 6 June 2006 Equilibrium studies involved in the CoII, NiII, CuII, ZnII-2-pyridinccarboxaldehyde (pyal)(A)-L-glutamic acid (glu) and L-aspartic acid (asp)(B) systems at \(T\) = 25 °C and \(I\) = 0.1 mol dm-3(KNO3)show the formation of the Schiff base complexes of stoichiometry M(AB), M(AB)A and M(AB)2. Doth the stability constant and electronic spectral data indicate that in M(AD) and M(AD)A complexes, the Schiff base (AB) is tetradentate, while in M(AD)2 the Schiff base functions as tridentate. The electronic spectral measurements indicate that Co(AB) complex do have tetrahedral structure, while the Ni(AB) and Cu(AB) complexes have square planar geometry. The M(AB)2 complexes in the CoII and NiII systems were found to have octahedral structure. Mulliken charge density and atomic orbital population analysis for the Schiff base ligands have also been done