Flash photolysis electron spin resonance and CIDEP studies of radicals derived from nitrogen heterocyclics. II. The photophysics and photochemistry of the methylpyrazines

Application of the CIDEP phenomenon is extended to the identification of the specific triplet energy levels which react to produce radicals in pyrazine and its methyl derivatives. Advantage is taken of the proximity of ³nπ and ³ππ states in which the opposite signs of the zero-field coupling constants cause triplet mechanism polarization of opposite phase in the derived radicals. The electronic natures of the radicals observed parallel those of the triplet states from which they are formed.