硫磺素型聚乳酸/苯磺酸室温磷光体系的构建

Construction of Room Temperature Phosphorescence System of Thioflavin-based Polylactide/Benzenesulfonic Acid

在硫磺素上分别引入给电子基氧、硫和甲氧基,合成出2-[4-(苯并噻唑-2-基)苯氧基]乙-1-醇(BT-OH)、2-{[4-(苯并噻唑-2-基)苯基]硫代}乙-1-醇(BT-SH)和2-[4-(苯并噻唑-2-基)-2-甲氧基苯氧基]乙-1-醇(BT-M-OH)3种硫磺素衍生物.利用硫磺素衍生物作为引发剂引发D,L-丙交酯聚合,得到3种硫磺素型聚乳酸,再加入苯磺酸,构建出可在室温下产生磷光的硫磺素型聚乳酸/苯磺酸体系,实现了从荧光到磷光的可调分子发射,其中磷光寿命最长达108.19 ms.研究发现,引入苯磺酸会使硫磺素型聚乳酸产生分子内电荷转移态,质子化效应导致绿色和橘色的磷光发射.

The electron-donating groups,—OH,—SH and —MeOH,were respectively introduced on thioflavin,and three thioflavin derivatives,2-[4-(benzothiazole-2-yl)phenoxy ethan-1-ol](BT-OH),2-{[4-(benzothiazole-2-yl)phenyl]thio}ethan-1-ol(BT-SH)and 2-[4-(benzothiazole-2-yl)-2-methoxyphenoxy]ethan-1-ol(BT-M-OH),were synthesized. The derivatives were used as initiators for the polymerization of D,Llactide to obtain three thioflavin-based polylactides. Benzenesulfonic acid was subsequently added to construct thioflavin-based polylactide/benzenesulfonic acid system that can produce room temperature phosphorescence.The tunable molecular emission from fluorescence to phosphorescence was realized,and the longest life of phosphorescence is 108.19 ms. The results reveal that the introduction of benzenesulfonic acid can cause the thioflavin-based polylactide to produce an intramolecular charge-transfer state,and the protonation effect leads to green and orange phosphorescent emission.