Collect. Czech. Chem. Commun. 1992, 57, 1065-1071

EPR Study of Nitroxyl Radicals of Substituted 5-Anilinotriazoles, 5-Anilinotetrazoles, and 2-Anilinobenzimidazoles

Ladislav Omelkaa, Michael Meskeb, Vladimír Cholvada, Jan Světlíkc and Manfred Schulzb

a Department of Physical Chemistry, Slovak Technical University, 812 37 Bratislava, Czechoslovakia
b Department of Synthetic Chemistry, Technical University "Carl Schorlemmer", Leuna-Merseburg, 4200 Merseburg, Germany
c Department of Analytical Chemistry, Pharmaceutical Faculty Comenius University, 832 Bratislava, Czechoslovakia


Substituted 5-anilinotriazoles V, 5-anilinotetrazoles VI and 2-anilinobenzimidazoles VII were oxidized by RO2 radicals to the corresponding nitroxyls VIII-X in a non-polar medium. The nitroxyls were characterized by the distribution of spin density into both benzene and N-heterocyclic rings. The influence of substitutents at various positions on the values of aNNO splitting constant was evaluated. The EPR spectral parameters of nitroxyls VIII-X were compared with those for the diphenylnitroxyl radical IV.