Nucleophilic effects on the deprotonation of phenol radical cations

Considering dependence on their electronic structure, in non-polar surroundings phenol radical cations exhibit lifetimes between 100 and 500 ns and decay by deprotonation forming phenoxyl radicals. Adding various quenchers of different nucleophilicity, we determined a set of rate constants For the acceleration of deprotonation i.e. the reaction of phenol radical cations with the nucleophiles. The data are basically discussed in terms of Reichardt's polarity scale, also considering effects like competing electron transfer aided by comparing the differences of calculated adiabatic ionization potentials as well as spin densities and local charges on heteroatoms for phenols and the quenchers. (C) 2001 Elsevier Science B.V. All rights reserved.