Photosensitized Electron-Transfer Reactions. Interception of the Geminate Radical Ion Pair

Journal of the American Chemical Society

Volumn 105, Issue 5, 1983, Pages 1386-1387

  Mattes, Susan L ^a   Farid, Samir ^a  

^a EASTMAN KODAK COMPANY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 33845551314     PISSN: 00027863     EISSN: 15205126     Source Type: Journal    
DOI: 10.1021/ja00343a061     Document Type: Article

References (17)

1. Mattes, S. L.; Farid, S. Acc. Chem. Res. 1982, 15, 80 and references therein.
2. Mattes, S. L.; Farid, S. J. Chem. Soc., Chem. Commun. 1980, 126.
3. The formation of 1 or a mixture of 1 and 2 depends on the sensitizer used. With DCA as a sensitizer, 1 and 2 are formed in similar amounts. In this reaction the formation of 2, a dehydrodimer, is accompanied by an equal yield of cis- and trans-dihydrodicyanoanthracene. The details of this reaction will be given in another publication.
4. Neunteufel, R. A.; Arnold, D. R. J. Am. Chem. Soc. 1973, 95, 4080.
5. 3CN are 310 and 130 M″1, respectively. The lifetimes of the singlet states of these compounds are 19.6 and 15.2 ns, respectively.
6. The quantum yield (01+2)., at [D] = 0.1 is ca. 0.033 for TCA vs. 0.15 for DCA.
7. Schulten, K.; Staerk, H.; Weller, A.; Werner, H. J.; Nickel, B. Z. Phys. Chem. Wiesbaden 1976, 101, 371.
8. Weller, A. Phys. Chem. Wiesbaden 1982, 130, 129. See also ref 2.
9. a is the overall efficiency of dimerization via the intercepted geminate pair. The energy-wasting steps along this path are the cleavage of the biradical and/or reverse electron transfer in the intermediate S”-/D+. -D. The latter process is not shown in the scheme.
10. The involvement of similar chain propagation steps is frequently encountered in cyclobutadimerization whenever the oxidation potential of the dimer is higher than that of the monomer.10 The cyclobutane 3 does not quench the fluorescence of DCA, which shows that this condition applies for the present system. There are also several examples of reversible cyclizations” analogous to D-D+ 3+.
11. Ledwith, A. Acc. Chem. Res. 1972, 5, 133.
12. Ledwith, A. J. Chem. Soc. C 1970, 2508.
13. Evans, T. R.; Wake, R. W.; Jaenicke, O. In “The Exciplex”; Gordon, M.; Ware, W. R., Eds.; Academic Press: New York, 1975; p. 345.
14. Majima, T.; Pac, C.; Sakurai, H. J. Am. Chem. Soc. 1980, 102, 5265 and references therein.
15. The efficiency of ion separation from the pair TCA./BP+” is ca. 1.6 times higher than that of the TCA pair, as judged by an increase in 01+2 with increasing [BP]/[D].
16. In the electron-transfer-sensitizedI photooxygenation of D, the biradical D-D and the radical cation D-D are intercepted by 02 forming 3, 3,6, 6-tetraphenyl-1, 2-dioxane.
17. This dioxane was reported first by Haynes: Haynes, R. K.; Probert, M. K. S.; Wilmot, J. D. Aust. J. Chem. 1978, 31, 1737.