Synthesis and physio-chemical studies of some ternary complexes containing vitamin as one of the ligands

Abstract

Ternary complexes provide models for metalloenzymes and scveral other biological processes involving metal ions. These have great functional values in nature, such as in blood (hemoglobin) which is an iron-complex and functions as thc oxygen carrier of the blood stream. The principles of coordination chemistry will thus allow an increasing understanding of the structure and dynamic features involved in biochemical processes. Ternal)' metal complexes of type [MAL], where M=Cu(II), Ni(IT), & Zn(ll), A=Ascorbic Acid (AsA), Pyridoxine (Pyri), Nicotinic Acid (Nia) and L=aalanine( a-ala), Glycine(gly), Phenylalanine(ph-ala), and Tyrosine(tyro) havc been investigated potentiometrically at 2SoC and at ionic strength of O.2M(NaCI04). The stability constants have been detemlined using SCOGS (Stability Constant of Gcneralized Species) compulcT program. The stabilities in ternary complexes have been discussed in lernls of ligandligand interaction, steric statistical, basicity of the ligands, nature of donor sites and ellargc neutralization tactors. The stabilization is expressed in tenns of L\logK. The L\logK values and percentage species computed gave parallel evidence for the stabilization of ternary complexes. The stabilitics of ternary complexes have been quantitatively compared with each other. Ternary complexes containing Pyridoxine (Pyri) are found to be more stable than the corresponding complexes containing Ascorbic Acid(AsA) and Nicotinic acid(Nia). With respect to ligand L, the stability of ternmy complexes increases in order: glycine < a-alanine < phcnylalanine < tyrosine. Ternary complexes of Ni(JI) are found to be less stable than thc corresponding Cu(lI) and Zn(lI) complexes. The fOl1llalionof the complexes have been confinued by LN spectral sludies and Cyelic Voltammogram.