The Journal of Physical Chemistry A

Photohydration of benzophenone in aqueous acid

M Ramseier, P Senn, J Wirz

Index: Ramseier, Markus; Senn, Paul; Wirz, Jakob Journal of Physical Chemistry A, 2003 , vol. 107, # 18 p. 3305 - 3315

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Citation Number: 70

Abstract

Why is the triplet state of aromatic ketones quenched by protons? The long-known but unexplained quenching process was investigated in detail for benzophenone (1). Adiabatic protonation of triplet benzophenone, 3 1, encounters a state symmetry-imposed barrier, because the electronic structure of 3 1 is n, π*, while that of its conjugate acid, 3 1 H+, is π, π*. Hence, the rate of protonation of 3 1, k H+= 6.8× 108 M-1 s-1, is well below the ...