Photophysics and photochemical reactions with electron acceptors of an anellated HANTZSCH-ester

Abstract

3,6-Dimethyl-9-phenyl-l,3,4,5,6,8,9,1O-octahydropyrano-[4,3-b:4',3'-e]-pyridine-l,8-dione (3) was prepared as first derivative of a novel substance class exhibiting a 1,4dihydropyridine structural element. Diazonium, iodonium, sulfonium and phosphonium salts act as electron acceptors both for ground state charge transfer complex formation and in single electron transfer processes (SET) with excited states of compound 3. Solvents strongly influence the rate constants of fluorescence quenching. Those containing a hydroxyl group decrease these rate constants as well as the quantum yields of SET due to higher solvent reorganization energies. Some expressions have been developed to describe the strong solvent effect. Due to a less effective population of the triplet state, the quantum yields of the SET'S are low.