Structure and conformational properties of some radicals from thiazolyl derivatives

The radical anions of 2.2?-bithiazolyl (I), 2-phenylthiazole (II), 2-(2-thienyl)thiazole (III), dithiazol-2-yl ketone (IV), and 2-nitrothiazole (V) exist as contact ion pairs in ethereal solvents. Whenever the organic anion contains two adjacent binding sites formation of chelate rings occurs, as revealed by examining the temperature and solvent dependence of the alkali hyperfine splitting. As a consequence the conformational stability of these radicals is markedly different from that of the analogous thiophen derivatives.