Lamp versus Laser Photolysis of a Bichromophoric Dichloroalkane: Chemical Evidence for the Two-Photon Generation of the 1,5-Diphenylpentanediyl Biradical
- 1 January 1996
- journal article
- research article
- Published by American Chemical Society (ACS) in The Journal of Organic Chemistry
- Vol. 61 (11) , 3773-3777
- https://doi.org/10.1021/jo960033q
Abstract
Low intensity (lamp) photolysis of 1,5-dichloro-1,5-diphenylpentane (1) leads to the formation of the 1-chloro-1,5-diphenylpentyl radical (7) through C−Cl bond cleavage. Radical 7 leads to the final products through typical free radical reactions. No cyclopentanes are formed under low intensity conditions. In contrast, high intensity laser irradiation leads to C−Cl photocleavage of radical 7 to yield the 1,5-diphenylpentanediyl biradical (11), which results in the formation of isomeric cis- and trans-1,2-diphenylcyclopentanes; the behavior of these biradicals agrees well with that observed when their precursor is 2,6-diphenylcyclohexanone. Two-color two-laser experiments suggest that both singlet and triplet biradicals are formed, even if only the latter are detectable with nanosecond techniques.Keywords
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