Study of 'Transition State' with Applied Potential [Mn – Sulfonamides – Cephalothin] System

M.S. Parihar and F. Khan*

 

Electrochemical Laboratory, Department of Chemistry, Dr. H.S. Gour University, Sagar-4700 003, M. P. India

Received 11 September 2007; accepted 13 May 2008

 

 

Abstract

Kinetic parameters and stability constants of [Mn – sulfonamides – cephalothin] system were reported at pH = 7.30 ± 0.01 in 1.0 M NaCO₄ at 25 ºC. The sulfonamides were sulfadiazine, sulfisoxazoe, sulfamethaxyzoe, sulfamethazine, sulfathiazoe, sulfacetamide and sulfaniamide as primary ligands, and cephalothin as secondary ligand. Values of transfer coefficient (α) varied from (0.41 to 0.59), showing that transition state behaves between oxidant and reductant response to applied potential and it adjusts itself in such a way that the transition state is located midway between dropping mercury electrode and solution interface. The rate constants (k) varied from 3.61 x 10^-3 cm.sec.^-1 to 9.93 x 10^-3 cm.sec.^-1, confirming that the electrode processes were quasi reversible. Small changes in potential not only affect the rate of the electrochemical reaction, but also strongly affect the rate constant. Values of stability constants (og β) varied from 1.75 to 9.13, showing that these drugs or their complexes could be used against Mn toxicity.

Keywords: electrode kinetics in [Mn – sulfonamides – cephalothin] system.

 

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References

1. S. Bellu and M. Rizzotto, Quim. Nova 30(5) (2007) 1136.        [ Links ]

2. L. S. Goodman and Giman’s, The Pharmacological Basis of Therapeutics, 11^th ed., The McGraw-Hill Co., New York, 2006.

3.  F. Martinez, C.M. Avila and A. Gomez, J. Braz. Chem. Soc. 14(5) (2003) 803.

4. A. Cleasby, A. Wonacott, T. Skarzynski, R.E. Hubbard, G.J. Davies, A.E. Proudfoot, A.E. Bernard, M.A. Payton, T.N. Well, Nature Struct. Biol. 3 (1996) 470.

5. A. Mastrolorenzo and C.T. Supuran, Metal Based Drug 7 (2000) 49.

6. L. Meites, Polarographic Technique, 2^nd ed., Interscience Publishers, New York, 1965, p. 62.

7. P.J. Gellings, Z. Elektrochem. 66 (1962) 477; Ber. Bun. Physik. Chem. 67 (1963) 799.

8. D. Deford and D.N. Hume, J. Am. Chem. Soc. 73 (1951) 5321.

9. W.B. Schaap and D. L. McMaster, J. Am. Chem. Soc. 83 (1961) 4699.

10. R.C. Kapoor, B.S. Aggarwal, Principles of Polarography, 1^st ed., Wiley Eastern Limited, New Delhi, 1991, p. 40.

11. A.E. Martell, Chemistry of Metal Chelate Compounds, 2^nd ed., Prentice Hall Inc., America, 1953, p. 134.

12. F. Khan, J. Chin. Chem. Soc. 52 (2005) 569.

13. R. Tamamushi and N.Z. Tanaka, Phys. Chem. New Folge 39 (1963) 117.

14. R. Tamamushi, K. Ishibashi and N.Z. Tanaka, Phys. Chem. New Folge 35 (1962) 211.

15. P.W. Atkins, Physical Chemistry, W.H. Freeman and Co., San Francisco, 1978, p. 959.

16. F. Khan, J. Chin. Chem. Soc. 54 (2007) 673.

 

* Corresponding author. E-mail address: faridkhan58@yahoo.com