College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou, Jiangsu, 215123, China.
Institute of Molecular Enzymology, School of Biology and Basic Medical Sciences, Soochow University, Suzhou, China.
Nat Commun. 2021 Apr 20;12(1):2339. doi: 10.1038/s41467-021-22685-0.
Developing organic photoluminescent materials with high emission efficiencies in the solid state under a water atmosphere is important for practical applications. Herein, we report the formation of both intra- and intermolecular hydrogen bonds in three tautomerizable Schiff-base molecules which comprise active hydrogen atoms that act as proton donors and acceptors, simultaneously hindering emission properties. The intercalation of water molecules into their crystal lattices leads to structural rearrangement and organic hydrate luminogen formation in the crystalline phase, triggering significantly enhanced fluorescence emission. By suppressing hydrogen atom shuttling between two nitrogen atoms in the benzimidazole ring, water molecules act as hydrogen bond donors to alter the electronic transition of the molecular keto form from nπ* to lower-energy ππ* in the excited state, leading to enhancing emission from the keto form. Furthermore, the keto-state emission can be enhanced using deuterium oxide (DO) owing to isotope effects, providing a new opportunity for detecting and quantifying DO.
在水气氛下开发固态下具有高光致发光效率的有机光致发光材料对于实际应用非常重要。在此，我们报告了三种互变异构席夫碱分子中形成的分子内和分子间氢键，这些分子包含活性氢原子，它们既可以作为质子供体又可以作为质子受体，同时阻碍发光性质。水分子插入其晶格中会导致在晶相中原位形成有机水合发光体，从而引发显著增强的荧光发射。通过抑制苯并咪唑环中两个氮原子之间的氢原子穿梭，水分子充当氢键供体，将分子酮式的电子跃迁从 nπ* 改变为激发态下较低能量的 ππ*，从而增强酮式的发射。此外，由于同位素效应，使用重水（DO）可以增强酮态的发射，这为检测和定量 DO 提供了新的机会。
