Photochemistry of substituted cyclic enones. Part 11.¹ Synthesis and photophysics of 5-arylalkyl-3-phenylcyclopentenones

Abstract

The photophysical properties of 3-phenyl-5-[2-(1-naphthyl)ethyl]cyclopent-2-enone and 5-[2-(1-naphthyl)methyl]-3-phenylcyclopent-2-enone have been compared with those of their constituent alkylated chromophores 1-ethylnaphthalene, 3-phenyl-5-(2-phenylethyl)cyclopent-2-enone and 3-phenyl-5-benzylcyclopent-2-enone by means of UV absorption spectroscopy, steady state and time resolved low temperature emission spectroscopy and laser flash photolysis. In mixed solvent low temperature glasses such as ethanol–isopentane–diethyl ether (2∶5∶5, v/v) (EPA) phosphorescence decay of all the enones shows multiexponential behaviour consistent with different lifetimes at different solvent sites. The naphthalene derivatives also show a longer lived emission consistent with slow processes involving a naphthalene localised triplet excited state. By contrast in fluid solution flash photolysis experiments reveal that there is rapid equilibration between the enone- and naphthalene-localised states.

References

1. Part 10. M. T. M. Clements and T. B. H. McMurry, J. Chem. Res. (S), 1993, 344.
2. M. T. Crimmins, Chem. Rev., 1988, 88, 1453.
3. D. I. Schuster, G. E. Heibel and J. Woning, Angew. Chem., Int. Ed. Engl., 1991, 30, 1345.
4. D. I. Schuster, G. Lem and N. A. Kaprinidis, Chem. Rev., 1993, 93, 3.
5. J. M. Kelly, T. B. H. McMurry and D. N. Work, J. Chem. Soc., Chem. Commun., 1987, 280; J. Chem. Soc., Perkin Trans. 2, 1990, 981.
6. M. T. M. Clements, K. J. Crowley, P. V. Kavanagh, M. A. Lennon, T. B. H. McMurry and M. P. Napier, J. Chem. Res., 1991, (S) 318; (M) 2920 and earlier papers in the series.
7. M. T. M. Clements and T. B. H. McMurry, J. Chem. Soc., Chem. Commun., 1986, 1104; M. T. M. Clements and T. B. H. McMurry, Can. J. Chem., 1987, 65, 1810.
8. P. V. Kavanagh, J. M. Kelly, T. B. H. McMurry and J. P. James, J. Chem. Soc., Chem. Commun., 1993, 231.
9. A. L. Wilds and T. L. Johnson, J. Am. Chem. Soc., 1945, 67, 286.
10. R. B. Fox, T. R. Price, F. R. Cozzens and J. R. McDonald, J. Chem. Phys., 1972, 57, 2284.
11. G. N. Lewis and M. Kasha, J. Am. Chem. Soc., 1944, 66, 2100.
12. S. L. Murov, I. Carmichael and G. L. Hug, Handbook of Photochemistry, Marcel Dekker, New York, 1993.
13. D. E. Breen and R. A. Keller, J. Am. Chem. Soc., 1968, 90, 1935.
14. I. Carmichael and G. L. Hug, J. Phys. Chem. Ref. Data, 1986, 15, 1.
15. A. A. Lamola, P. A. Leermakers, G. W. Byers and G. S. Hammond, J. Am. Chem. Soc., 1965, 87, 2322.
16. O. Schnepp and M. Levy, J. Am. Chem. Soc., 1962, 84, 172.
17. H. E. Zimmerman and R. D. McKelvey, J. Am. Chem. Soc., 1971, 93, 3638.
18. J. R. Bunting and N. Filipescu, J. Chem. Soc. (B), 1970, 1750.
19. M. Guha, unpublished results.
20. P. J. Wagner and T. Nakahira, J. Am. Chem. Soc., 1973, 95, 8474.
21. M. Magnifico, E. J. O'Connell, A. V. Fratini and C. M. Shaw, J. Chem. Soc., Chem. Commun., 1972, 1095.
22. N. C. Yang and S. Murov, J. Chem. Phys., 1966, 45, 4358.
23. R. N. Griffin, Photochem. Photobiol., 1968, 7, 175.
24. G. W. Suter, U. P. Wild and K. Schaffner, J. Phys. Chem., 1986, 90, 2358.
25. D. R. Kearns, G. Marsh and K. Schaffner, J. Chem. Phys., 1968, 49, 3316; G. Marsh, D. R. Kearns and K. Schaffner, Helv. Chim. Acta, 1968, 51, 1890; J. Am. Chem. Soc., 1971, 93, 3129.
26. D. G. Farnum, A. Mostashari and A. A. Hagedorn, J. Org. Chem., 1971, 36, 698.
27. J. M. Kelly, W. J. van der Putten and D. J. McConnell, Photochem. Photobiol., 1987, 45, 167.
28. M. S. Newman, J. Org. Chem., 1944, 9, 518.
29. M. Hatanaka, Y. Himeda and I. Veda, Tetrahedron Lett., 1991, 32, 4521.