A microelectrode study of the influence of electrolyte on the reduction of quinones in aprotic solvents

Abstract

Au microdisc electrodes are used to extend previous studies of the influences of the electrolyte on the voltammetry of quinones, Q, in DMF to solutions with only a low electrolyte concentration. It is shown that the 1e^- products, the semiquinones, interact with the cations of all electrolytes studied (Bu₄N⁺, Na⁺, Li⁺ and Mg²⁺) and these interactions are stronger for o-quinones than p-quinones; association constants for ion pairing are reported. The voltammetry for the second 1e^- reduction step is largely determined by the solubility of the product, QM₂.

References

1. M. E. Peover, in Electroanalytical Chemistry, ed. A. J. Bard, Marcel Dekker, 1962, vol. 2, p. 1.
2. C. K. Mann and K. K. Barnes, Electrochemical Reactions in Non-Aqueous Systems, Marcel Dekker, 1970, p. 190.
3. D. H. Evans, in Encyclopaedia of Electrochemistry of the Elements, ed. H. Lund, Marcel Dekker, 1978, vol. XII, p. 198.
4. M. E. Peover and J. D. Davies, J. Electroanal. Chem., 1963, 6, 46.
5. B. R. Eggins, J. Chem Soc., Chem. Commun., 1969, 1267.
6. T. Nagaoka, S. Okazaki and T. Fujinaga, J. Electroanal. Chem., 1982, 133, 82.
7. P. D. Jannakoudakis, P. Karabinas and E. Theodoridou, Z. Phys. Chem. Neue Folge, 1982, 131, 89.
8. V. D. Bezuglyi, L. V. Shkodina and T. A. Alekseeva, Soviet Electrochem., 1984, 1282.
9. C. Rüssel and W. Jaenicke, J. Electroanal. Chem., 1986, 199, 139.
10. K. J. Stutts and G. W. Eastland, J. Electroanal. Chem., 1987, 235, 357.
11. M. Oyama, F. Marken, R. D. Webster, J. A. Cooper, R. G. Compton and S. Okazaki, J. Electroanal. Chem., 1998, 451, 193.
12. D. Pletcher and H. Thompson, J. Chem. Soc., Faraday Trans., 1997, 93, 3669.
13. J. A. Alden, F. Hutchinson and R. G. Compton, J. Phys. Chem. B, 1997, 101, 949.
14. L. Meites, Polarographic Techniques, Interscience, 1965, p. 267.
15. J. D. Norton, W. E. Benson, H. S. White, B. D. Pendley and H. D. Abruna, Anal. Chem., 1991, 63, 1909.
16. K. B. Oldham, T. J. Cardwell, J. H. Santos and A. M. Bond, J. Electroanal. Chem., 1997, 430, 25.
17. K. B. Oldham, T. J. Cardwell, J. H. Santos and A. M. Bond, J. Electroanal. Chem., 1997, 430, 39.
18. C. Amatore, M. F. Bento and M. I. Montenegro, J. Electroanal. Chem., 1997, 439, 173.
19. K. B. Oldham, J. Electroanal. Chem., 1988, 250, 1.
20. S. M. Drew, R. M. Wightman and C. Amatore, J. Electroanal. Chem., 1991, 317, 117.