The photochemical reaction of 1,4-naphthaIenedicarbonitrile (NDN) with benzylic derivatives of the general formula PhCHRX (R = H, Ph; X = H, C, 0, S, Si, Sn-bonded substituents) has been investigated. The competition between C-H and C-X bond cleavage in the photochemically created radical cation PhCHRX" is revealed by the different chemical products formed, viz. 5,1l-methanodibenzo[a,e]cyclooctenes (2), from proton transfer and coupling of the radicals within the cage, and 2-benzyl- (3) and 1-benzyl-I ,2-dihydronaphthalenes (4), as well as 4-benzyl-1-naphthalenenitriles (5), from the reaction between the radical anion NDN'- and the neutral radicals PhCHR' or PhCRX'. With the alcohols, the hydroxylic proton is easily transferred. Measurement of reaction quantum yield and fluorescence quenching and thermochemical calculations support the mechanism proposed
Photochemical reaction between 1,4-naphthalenedicarbonitrile and a-substituted benzylic derivatives
D'ALESSANDRO, Nicola;
1989-01-01
Abstract
The photochemical reaction of 1,4-naphthaIenedicarbonitrile (NDN) with benzylic derivatives of the general formula PhCHRX (R = H, Ph; X = H, C, 0, S, Si, Sn-bonded substituents) has been investigated. The competition between C-H and C-X bond cleavage in the photochemically created radical cation PhCHRX" is revealed by the different chemical products formed, viz. 5,1l-methanodibenzo[a,e]cyclooctenes (2), from proton transfer and coupling of the radicals within the cage, and 2-benzyl- (3) and 1-benzyl-I ,2-dihydronaphthalenes (4), as well as 4-benzyl-1-naphthalenenitriles (5), from the reaction between the radical anion NDN'- and the neutral radicals PhCHR' or PhCRX'. With the alcohols, the hydroxylic proton is easily transferred. Measurement of reaction quantum yield and fluorescence quenching and thermochemical calculations support the mechanism proposedI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
