Bipin K Shah, A. Gusev, M. Rodgers
Jun 19, 2004
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Influential Citations
8
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Journal
Journal of Physical Chemistry A
Abstract
Photolysis of tert-butyl aroylperbenzoates (BAPs) 1−4 in benzene and acetonitrile at 335 or 267 nm produces the S1 states (λmax ≈ 590 nm) that rapidly intersystem cross (kISC ≈ 1.3 × 1011 s-1) into the triplet states (λmax ≈ 560 nm, τT = 0.6−0.7 ns in benzene). Results from the 267 nm excitation experiments of 1 in acetonitrile suggest the rate of the S2 → S1 internal conversion (kS2→S1 = 1.6 × 1012 s-1) is similar to that of benzophenone and p-iodobenzophenone. The rate of the S1 → T1 intersystem crossing is not affected by the solvent or the excitation wavelength. However, decay of the triplet states of 1 and p-iodobenzophenone is faster in acetonitrile than in benzene. Intramolecular triplet energy dissipation to a repulsive excited triplet state of the O−O bond of BAPs may be a possible mechanism. The results obtained from semiempirical and ab initio calculations have been presented.