Studies on mixed ligand complexes involving ligands of biological importance [Ni(II), Zn(II) or Cd(II)-1,10-phenanthroline — or 2,2′-bipyridyl-histidine]
The formation of mixed ligand complexes of the title metal ions with 1,10-phenanthroline (Phen) or 2,2′-bipyridyl (Bipy) in presence of histidine (His) has been studied pH-metrically. The stepwise formation of 1∶1∶1 mixed ligand complexes has been inferred from the potentiometric titration curves. Initially, a 1∶1 metal—Phen or—Bipy complex is formed in the lower buffer region and then the addition ofHis takes place resulting in 1∶1∶1 ternary complex formation. The formation constants (K MAL ) of the resulting mixed ligand complexes have been calculated at 30±1°C (μ=0.1 KNO3) and the values have been found to be higher than the formation constants of 1∶2 and lower than those of 1∶1 metal—His complexes. The order of stability in terms of metal ions follows the order, Ni(II)>Zn(II)>Cd(II).
KeywordsHistidine Phen KNO3 Potentiometric Titration Ternary Complex
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- 1.J. D. Joshi, I. P. Mavani, andP. K. Bhattacharya, Indian J. Chem.11, 820 (1973).Google Scholar
- 2.I. V. Pyatnitskii andG. N. Trochinskaya, Zh. anal. Khim.28, 704 (1973).Google Scholar
- 3.M. V. Chidambram andP. K. Bhattacharya, Indian J. Chem.9, 1274 (1971).Google Scholar
- 4.B. R. Panchal andP. K. Bhattacharya, Indian J. Chem.11, 394 (1973).Google Scholar
- 5.K. N. Leong andM. W. Lister, Canad. J. Chem.50, 3573 (1972).Google Scholar
- 6.R. L. Dutta andDhurubananda De, J. Indian Chem. Soc.46, 62, 74 (1969).Google Scholar
- 7.G. A. L'Heureux andA. E. Martell, J. Inorg. Nucl. Chem.28, 481 (1966).Google Scholar
- 8.N. C. Li andR. A. Manning, J. Amer. Chem. Soc.77, 5255 (1955).Google Scholar
- 9.R. Leberman andB. R. Rabin, Trans. Faraday Soc.55, 1660 (1959).Google Scholar
- 10.A. Chakarvorty andF. A. Cotton, J. Phys. Chem.67, 2878 (1963).Google Scholar