Deactivation of triplet phenyl alkyl ketones by conjugatively electron-withdrawing substituents

PJ Wagner, EJ Siebert

Index: Wagner, Peter J.; Siebert, Elizabeth J. Journal of the American Chemical Society, 1981 , vol. 103, # 24 p. 7329 - 7335

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Citation Number: 84

Abstract

Abstract: Para-cyano,-carbomethoxy, and-acyl substituents decrease the triplet reactivity of valerophenone (7-hydrogen abstraction), whereas comparable meta substituents increase reactivity. Spectroscopic results are presented which indicate that para-(-R) substituents lower a,** triplet energies so much more than n, a* energies that the lowest triplets become largely T, T* in nature. Meta-(-R) substituents do not stabilize a, a* triplets enough to invert ...