engleski

Synthesis, photochemistry and photophysics of new butadiene derivatives: Influence of the fluoro, dimethylamino and nitro substituents on the molecular structure and photoinduced behavior

Novel p-fluoro, p-dimethylamino and p- nitro substituted arylbutadiene derivatives were synthesized by Wittig reaction and their diverse photochemistry and photophysics were established and explained. Under excitation mono- and difluoro derivatives undergo photoinduced intramolecular cycloaddition. The parent mono- dimethylamino substituted derivative undergoes the same reaction type giving the photocycloadduct in lower yield and with incomplete consumption, whereas its bis(dimethylamino) analogue shows only geometrical isomerization due to the steric effect of the substituents. Mono- and dinitro derivatives show photochemical unreactivity. Conjugated analogues with similar structures display dramatically different photoinduced behavior, revealing how changes of the nature of substituents impact their photophysics and photochemistry. The computational investigation of the effects of the conformational diversity within the steric influence of the starting geometric isomers on the photoreaction pathway and energy profiles of the Wittig reaction is performed for the first time.

arylbutadiene ; photochemistry ; photophysics ; substituent impact ; Wittig reaction

University of Pannonia, Faculty of engineering