摘要
Bismaleimides bearing 2,5-diphenyl-l,3,4- oxadiazole chromophores at para, meta, ortho position and corresponding saturated bissuccinimides were synthe- sized. 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 spectro- scopy. The electron coupling of ground state of p- bismaleimide is stronger than those of m- and o- bismaleimides.p-Bissuccinimide displays increasing fluor- escence quantum yields with red shifts of 22-24 nm, compared to m-bissuccinimide. Polymerizable C=C bonds play a key role in the intramolecular fluorescence quenching.
Bismaleimides bearing 2,5-diphenyl-l,3,4- oxadiazole chromophores at para, meta, ortho position and corresponding saturated bissuccinimides were synthe- sized. 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 spectro- scopy. The electron coupling of ground state of p- bismaleimide is stronger than those of m- and o- bismaleimides.p-Bissuccinimide displays increasing fluor- escence quantum yields with red shifts of 22-24 nm, compared to m-bissuccinimide. Polymerizable C=C bonds play a key role in the intramolecular fluorescence quenching.
