POLAROGRAPHIC CHARACTERISTICS AND THERMODYNAMICS APPLIED IN [Cd - L-AMINO ACIDATES - VITAMIN-B7] TERNARY SYSTEM

The present work describes the complexe formation of the Cd (II) with amino acids (L-glutamine, L-asparagine, L-valine, L-leucine, α-alanine and glycine) as primary ligands and vitamin-B7 (β-biotin) as secondary ligand by polarographic technique. The Cd (II) formed 1: 1: 1, 1: 1: 2 and 1: 2: 1 complexes at pH = 7.30 ± 0.01, µ = 1.0 M KNO 3 . The Cd (II) showed the two electrons reversible reduction wave with diffusion controlled nature. The trend of the stability constants of the complexes with respect to primary ligand was L-glutamine < L-asparagine < L-valine < L-leucine < α-alanine < L-glycine. The thermodynamic parameters like enthalpy, free energy, and entropy change is also determined. The results showed that the complexes were lesser stable at high temperature and formed with the evolution of heat. 1-3 . The minerals mis-regulation leads to many serious diseases such as oxidative stress diabetes, amyotrophic lateral sclerosis, cancer, inflammatory, neurodegenerative, and potential to various toxic effects etc. 4-10 . In addition to these, toxic effects are reduced with the ligands therapy. The bioactive amino acids and vitamin-B7 complexes with the Cd (II) are also used to prevent excess metal accumulation and toxicity 11 . Amino acid side chain groups are involved in various biological functions such as the molecular recognition and catalytic activity of the enzyme active center and formation of an environment with the metal ions used to in medicinal fields 12 . Weak interactions involving functional groups of coordinated amino acids in metal complexes may mimic the modes and effects of the interactions in metalloproteins. Complexes of amino acids and vitamins with metal ions have great importance because of their physiological and pharmacological activities. Some of the research work reported antitumor activities 13-14 . Biotin is act as cofactor and coenzyme involved in vital biological process such as fatty acid synthesis, gluconeogenesis, amino acids metabolism, and carbon dioxide fixation reaction 15 . Therefore the combination of the amino acids and vitamin-B7 with Cd (II) are used to reduce the metal toxicity. The coordination chemistry of the Cd (II) metal ion has shown too significant for the organisms on complexation with the bioactive ligands by chelating nitrogen and oxygen donor ligands 16 . In the present work, we report the complex formation between Cd 2+ and some L-amino acids and β-biotin with the aim to ascertain the effects of size and basicity of ligand on the stability of complexes.