Flavosemiquinone model systems. Part 1. 4-Hydro-1-alkylpyrazinium radical cations

Abstract

Reduction of 1-alkylpyrazinium iodides in acidic media produces 4-hydro-1-alkylpyrazinium radical cations. These persistent species were identified and characterized by high, resolution e.s.r., and assignments of coupling constants were made on the basis of deuteriation experiments and Hückel MO correlations. The spin distribution in these radicals and in related systems, especially in flavosemiquinone cations, is discussed.