Frontiers of Chemical Science and Engineering
Synthesis and fluorescence behavior of 2,5-diphenyl-1,3,4-oxadiazole-containing bismaleimides and bissuccinimides
1. University of Wuerzburg, Institute of Organic Chemistry, Am Hubland, 97074 Wuerzburg, Germany; 2. Key Laboratory of Polymer Chemistry & Physics of Ministry of Education, College of Chemistry & Molecular Engineering, Peking University, Beijing 100871, China
Bismaleimides bearing 2,5-diphenyl-1,3,4-oxadiazole chromophores at , , position and corresponding saturated bissuccinimides were synthesized. Several synthetic strategies for these bismaleimides were discussed in detail. Almost no or very weak fluorescence was observed for these bismaleimides, however, the bissuccinimides show a strong fluorescence. The effect of molecular geometry on optical behavior and fluorescence quenching mechanism were investigated by UV-vis absorption and fluorescence emission spectroscopy. The electron coupling of ground state of -bismaleimide is stronger than those of - and -bismaleimides. -Bissuccinimide displays increasing fluorescence quantum yields with red shifts of 22–24 nm, compared to -bissuccinimide. Polymerizable C=C bonds play a key role in the intramolecular fluorescence quenching.