The Photochemistry of the Host-Guest Complex. VII. The Photoreaction of Dicyanopyrazine Derivatives Having a Crown Ether Moiety

Article abstract of DOI:10.1246/bcsj.55.3865

The irradiation of 4'-(5,6-dicyano-2-pyrazinyl)benzo-15-crown-5 and 5,6-dicyano-2-(3,4-dimethoxyphenyl)pyrazine in the presence of a tertiary or secondary amine caused reductive decyanation to give 5-decyano derivatives, which in turn gave bis(decyano) derivatives on further irradiation.Free-energy changes upon single-electron transfer from the amine to the excited state of dicyanopyrazine derivatives are exothermic for triethylamine and diethylamine, but endothermic for butylamine.The single-electron transfer was evidenced by the effect of the sodium ion on the quantum yields of the reaction products and the fluorescence quenching.