AM1, INDO/S and optical studies of carbocations of carotenoid molecules. Acid induced isomerization

Abstract

The mechanism of trans–cis isomerization of carotenoid molecules through the formation of the carotenoid carbocation (CarH⁺) intermediate in the presence of acid is presented. Various cis-isomers of carotenoids (β-carotene, canthaxanthin and 8′-apo-caroten-8′-al) are predicted from AM1 calculations of rotation barriers for CarH⁺, as well as from the stabilities of CarH⁺. AM1 dipole moments D and INDO/S optical transitions of CarH⁺ were calculated for all protonation sites. Optical spectra of CarH⁺ solutions exhibit broad lines in the region of 700–1000 nm with extinction coefficients of 1–3 × 10⁵ M^–1 cm^–1.

References

1. Y. Koyama, J. Photochem. Photobiol. B: Biol., 1991, 9, 265.
2. H. A. Frank, C. A. Violette, J. K. Trautman, A. P. Shreve, T. G. Owens and A. C. Albrecht, Pure Appl. Chem., 1991, 63, 109.
3. M. Mimuro and T. Katoh, Pure Appl. Chem., 1991, 63, 123.
4. R. V. Bensasson, E. J. Land and T. G. Truscott, Excited States and Free Radicals in Biology and Medicine, Oxford University Press, Oxford, 1993.
5. G. E. Bialek-Bylka, T. Hiyama, K. Yumoto and Y. Koyama, Photosynth. Res., 1996, 49, 245.
6. G. E. Bialek-Bylka, T. Tomo, K. Satoh and Y. Koyama, FEBS Lett., 1995, 363, 137.
7. J. Deisenhofer and H. Michel, Science, 1989, 245, 1463.
8. M. Kuki, Y. Koyama and H. Nagae, J. Phys. Chem., 1991, 95, 7171.
9. A. Bendich and J. A. Olson, FASEB J., 1989, 3, 1927.
10. A. Farmilo and F. Wilklinson, Photochem. Photobiol., 1973, 18, 447.
11. F. Wilklinson and W.-T. Ho, Spectrosc. Lett., 1978, 11, 455.
12. M. A. J. Rodgers and A. L. Betes, Photochem. Photobiol., 1980, 31, 533.
13. O. T. Kasaikina, Z. S. Kartasheva and A. B. Gagarina, Izv. Akad. Nauk SSSR, Ser. Khim., 1981, 536.
14. G. W. Burton and K. U. Ingold, Acc. Chem. Res., 1986, 19, 194.
15. K. U. Ingold, W. W. Bowry, R. Stoker and C. Walling, Procl. Natl. Acad. Sci. USA, 1993, 90, 45.
16. W. W. Bowry and R. Stoker, J. Am. Chem. Soc., 1993, 115, 6029.
17. N. I. Krinsky, Free Radical Biol. Med., 1989, 7, 617.
18. R. Peto, Doll, J. D. Buckley and M. B. Sporn, Nature, 1981, 290, 201.
19. R. G. Ziegler, Am. J. Clin. Nutr., 1991, 53, 251S.
20. W. F. Malone, Am. J. Clin. Nutr., 1991, 53, 305S.
21. M. M. Mathews-Roth, Pure Appl. Chem., 1991, 63, 147.
22. R. S. Becker, Photochem. Photobiol., 1988, 48, 369.
23. W. v. E. Doering, C. Sotiriou-Leventis and W. R. Roth, J. Am. Chem. Soc., 1995, 117, 2747.
24. W. v. E. Doering and T. Kitagawa, J. Am. Chem. Soc., 1991, 113, 4288.
25. K. Tsukida, K. Saiki and M. Sugiura, J. Nutr. Sci. Vitaminol., 1981, 27, 551.
26. K. Tsukida and K. Saiki, J. Nutr. Sci. Vitaminol., 1983, 29, 111.
27. Y. Hu, H. Hashimoto, G. Moine, U. Hengartner and Y. Koyama, J. Chem. Soc., Perkin Trans. 2, 1997, 2699.
28. A. S. Jeevarajan, C. C. Wei and L. D. Kispert, J. Chem. Soc., Perkin Trans. 2, 1994, 861.
29. M. Zardkoohi, J. F. Haw and J. H. Lunsford, J. Am. Chem. Soc., 1987, 109, 5278.
30. Carbonium Ions, Vol. 2, eds. G. A. Olah and P. v. R. Schleyer, Wiley-Interscience, New York, 1970, p. 963.
31. Stable Carbocation Chemistry, eds. G. K. S. Prakash and P. v. R. Schleyer, Wiley-Interscience, New York, 1997, p. 587.
32. R. Kuhn and C. Grundmann, Chem. Ber., 1938, 71B, 442.
33. A. J. Wassermann, J. Chem. Soc., 1954, 4329.
34. A. J. Wassermann, J. Chem. Soc., 1959, 986.
35. T. S. Sorensen, J. Am. Chem. Soc., 1965, 87, 5075.
36. Y. Koyama, T. Takii, K. Saiki and M. Tsukida, Photochem. Photobiophys., 1983, 5, 139.
37. Carotenoids. Volume 1B: Spectroscopy, eds. G. Britton, S. Liaaen-Jensen and H. Pfander, Birkhäuser Verlag, Basel-Boston-Berlin, 1995, pp. 13–62.
38. M. Khaled, A. Hadjipetrou and L. D. Kispert, J. Phys. Chem., 1990, 94, 5164.
39. J. A. Jeevarajan, C. C. Wei, A. S. Jeevarajan and L. D. Kispert, J. Phys. Chem., 1996, 100, 5637.