EXCIMER OF CONFORMATIONALLY FLEXIBLE MOLECULES: DIETHYL p-PHENYLENEDIACRYLATE AND METHYL 4-(β-METHOXYCARBONYLVINYL)-α-CYANOCINNAMATE

Conformationally flexible molecules of diethyl p-phenylenediacrylate (1) and methyl 4-(β-methoxycarbonylvinyl)-α-cyanocinnamate (2) exhibit excimer emission in concentrated solutions. The excimer of 1 is formed via excitation of the ground state aggregates of 1. In crystalline state, only 2, which has the crystal structure of B-type in Stevens’ classification, being different from the crystal structure (A-type) of 1, gives excimer emission. The stack-type structure is proposed for the excimers of 1 and 2.