NAPHTHYL DISELENIDES
199
4. E. J. Land, G. Porter and E. Strachan, Trans. Faraday
Soc., 57, 1885 (1961).
5. J. A. Bell and H. Linschitz, J. Am. Chem. Soc., 85, 528
(1963).
6. H. Paul, R. D. Small, Jr., and J. C. Scaiano, J. Am.
Chem. Soc., 100, 4520 (1978).
Figure 9 SOMO energies and their unpaired electron den-
sities of NaphSe and PhSe .
7. F. C. Thyrion, J. Phys. Chem., 77, 1478 (1973).
8. O. Ito and M. Matsuda, J. Am. Chem. Soc., 101, 1815
(1978).
●
●
9. T. J. Burkey and D. Griller, J. Am. Chem. Soc., 107,
246 (1985).
10. T. W. Scott and S. N. Liu, J. Phys. Chem., 93, 1393
(1989).
ence of 1,4-cyclohexadiene, indicating that the H-atom
abstraction abilities of these seleno radicals are quite
low. This is also supported by the steady-light pho-
tolysis; in the presence of 1,4-cyclohexadiene, the
decrease in the absorption bands of the diselenides
was not observed. Therefore, the addition reaction is
the only reaction responsible for the observed de-
11. Y. Yoshikawa, A. Watanabe and O. Ito, J. Photochem.
Photobiol. A: Chemistry, 89, 209 (1995).
12. T. Autrey, C. Devadoss, B. Sauerwein, J. A. Franz and
G. B. Shuster, J. Phys. Chem., 99, 869 (1995).
13. O. Ito, J. Am. Chem. Soc., 105, 850 (1983).
14. O. Ito, J. Org. Chem., 58, 1466 (1993).
15. A. Ouchi, Y. Koga, M. M. Alam, and O. Ito, J. Chem.
Soc., Perkin Trans. 2, 1705 (1996).
16. E. N. Ushakov, I. K. Lednev, and N. N. Magdesieva,
M. V. Alfimov, Khim. Vys. Energ., 24, 447 (1990).
17. E. N. Ushakov, I. K. Lednev, and M. V. Alfimov, Khim.
Vys. Energ., 25, 93 (1991).
18. D. Griller and J. A. Martinho Simoes, Sulfur-Centered
Reactive Intermediates in Chemistry and Biology,
C. Chargilialouglu and K.-D. Asmus, Ed., Plenum, New
York, (1989), p. 327.
19. O. Ito and M. Matsuda, Prog. Polym. Sci., 17, 827
(1992).
20. O. Ito, Trends Phys. Chem., 3, 245 (1992).
21. H. J. Reich, J. M. Renga, and I. L. Reich, J. Am. Chem.
Soc., 97, 5434 (1975).
22. S. L. Murov, Handbook of Photochemistry, Marcel
Dekker, 1973.
23. M. M. Alam, A. Watanabe and O. Ito, J. Org. Chem.
60, 3440 (1995).
24. J. J. Stewart, QCPE Bull., 9, 10 (1989).
25. P. K. Das, M. V. Encinas, S. Steenken and J. C. Scaiano,
J. Am. Chem. Soc., 103, 4162 (1981).
и
cay of NaphSe besides the recombination reaction
(Scheme I).
The molecular orbital (M.O.) energies and electron
и
densities of NaphSe were calculated by semiempiri-
cal restricted Hartree–Fock method using the opti-
mized geometry obtained by PM3 method [24]; the
results are shown in Figure 9. The reactivities of the
radicals can be explained from these MO parame-
ters [39]; the unpaired electron density of SOMO at
Se atom increase in the order of 1-NaphSeи Ͻ
2-NaphSeи Ͻ PhSe , which seems to be in accord
и
with the observed reactivities.
Since the S-centered radical has highly electro-
philic character, it would be expected that the seleno
radicals also have similar character in some extent. In
the addition reaction to alkenes, it has been anticipated
that the contribution of polar resonance structure in
the transition state of the reaction lowers the activation
energy [40]. The higher the electrophilicity of the se-
leno radical, the lower the SOMO energy. The order
of the SOMO energy is also in accord with the in-
creasing reactivity of the radicals obtained by the ex-
periments.
26. O. Ito and M. Matsuda, J. Org. Chem., 48, 2401 (1983).
27. S. Tomoda, M. Shimada and Y. Takeuchi, Nippon Ka-
gaku Kaishi 1466 (1989).
28. T. J. Burkey and D. Griller, J. Am. Chem. Soc. 107, 246
(1985).
29. K. U. Ingold, in Free Radicals J. K. Kochi, Ed., Wiley,
New York, (1973), Vol. 1, p. 37.
30. I. K. Lednev, E. N. Ushakov, and M. V. Alfimov, Catal.
Lett., 17, 167 (1993).
The present work is partly defrayed by the Grant-in-Aid on
Priority-Area-Research on “Photoreaction Dynamics” (No.
08218207) from the Ministry of Education, Science, Sports
and Culture.
31. B. Millard, K. U. Ingold, and J. C. Scaiano, J. Am.
Chem. Soc., 105, 5095 (1983).
BIBLIOGRAPHY
32. A. A. Oswald, K. Griesbaum, W. A. Thaler, and B. E.
Hudson, Jr., J. Am. Chem. Soc., 84, 3897 (1962).
33. J. I. G. Cadogan and I. H. Sadler, J. Chem. Soc B, 1191
(1966).
34. W. Stanley, M. R. VanDeMaker, and P. L. Kumler, J.
Chem. Soc. Chem. Commun., 700 (1974).
35. J. Y. Chu, D. G. Marsh, and W. H. H. Gunther, J. Am.
Chem. Soc., 97, 4905 (1975).
1. Y. Okamoto, in The Chemistry of Organic Selenium
Compounds, S. Patai and Z. Rappoport, Eds., Wiley,
New York, 1986, Vol. 1, Chap. 10, p. 331.
2. E. N. Deryagina, M. G. Voronkov, and N. A. Korchevin,
Russ. Chem. Reviews, 62, 1107 (1993).
3. G. Porter and M. W. Windsor, Proc. Roy. Soc. A, 245,
238 (1958).