92012-79-8Relevant academic research and scientific papers
Photochemical Transformations and Laser Flash Photolysis Studies of 1,4- and 1,2-Epoxy Compounds Containing 1,2-Dibenzoylalkene Moieties
Murty, B. A. R. C.,Kumar, C. V.,Dabral, V.,Das, P. K.,George, M. V.
, p. 4165 - 4171 (2007/10/02)
Photochemical transformations of a few 1,4- and 1,2-epoxy ketones have been investigated.Irradiation of a benzene solution of 1 gave a mixture of 3 (32percent) and dibenzoylacetylene (DBA, 6, 13percent), whereas the photolysis of 8 in methanol gave a mixture of the ester 12 (56percent) and DBA (22percent).Irradiation of 14 in benzene gave a mixture of the isomeric lactone 17 (25percent), 1,3-diphenylisobenzofuran (20, 20percent), and o-dibenzoylbenzene (23, 10percent).The photolysis of 24 in both benzene and methanol resulted in isomerization to the anthracene derivative 25 (6percent and 20percent).The same product (25, 38percent) was obtained in the thermolysis of 24.Plausible mechanisms for the formation of the various products have been discussed.Laser flash photolysis (337.1 nm) of 1, 8, and 14 in benzene and methanol led to the observation of short-lived transient species, characterized by absorption maxima at 405-490 nm and by lifetimes (τT) in the range 0.4-2.0 μs.Pulse-radiolytic observation of the same transients under energy-transfer sensitization as well as detailed quenching studies using oxygen, di-tert-butylnitroxide, azulene, ferrocene, and β-carotene led to the assignments of the transients as triplets.The quantum yields of triplet formation (ΦT) under direct laser excitation were estimated to be high (0.50-0.74).Upon laser flash photolysis, 24 produced the anthracene derivative 25 nearly within the laser pulse; the intermediacy of a triplet with τT ca.7 ns and ΦT ca.1 was established in this case by quenching studies involving 1-methylnaphthalene and 2,5-dimethyl-2,4-hexadiene.
