Lamp versus Laser Photolysis of a Bichromophoric Dichloroalkane: Chemical Evidence for the Two-Photon Generation of the 1,5-Diphenylpentanediyl Biradical.
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.
Pérez-Prieto
Julia
J
Departamento de Química Orgánica, Facultad de Farmacia, Universidad de Valencia, Vicent Andrés Estelles s/n, Burjasot, 46100 Valencia, Spain, Instituto de Tecnología Química, Universidad Politécnica de Valencia, Camino de Vera s/n, Valencia, 46071 Spain, and Department of Chemistry, University of Ottawa, Ottawa, Canada K1N 6N5.
Miranda
Miguel Angel
MA
García
Hermenegildo
H
Kónya
Klára
K
Scaiano
J. C.
JC