Hydrogen Donating Solvent Participation in the Photochemistry of Benzaldehyde and Deoxybenzoin: A 13C CIDNP Study
作者:Kuo Chu Hwang、Nicholas J. Turro、Heinz D. Roth
DOI:10.1021/jo00084a030
日期:1994.3
Photolysis of benzaldehyde (1; 90% C-13=O) in cyclohexane-d(12) results in the formation of benzaldehyde-h and -d with emissive CIDNP for the C-13=O function. This observation requires a secondary encounter of a free benzoyl radical with either phenylhydroxymethyl or cyclohexyl-d(11) radicals. Photolysis of deoxybenzoin (5; 99% C-13=O) and p-chloro-5 (99% C-13=O) in cyclohexane-d(12) also generates benzyldehyde-h and -d with the same emissive CIDNP for the C-13=O function. These observations are rationalized in terms of a previously unreported primary intermolecular deuterium abstraction by photoexcited deoxybenzoin from the (deuterated) solvent. This assignment is supported by the significantly decreased measured lifetime of triplet deoxybenzoin in cyclohexane-h and -d (429 and 724 ns, respectively) compared to the lifetime in benzene (847 ns).