Controlling Aggregation and Excited-State Intramolecular Proton Transfer in BODIPYs by Incorporation of 2‑(2-Hydroxyphenyl)quinazoline and Variation of Substituents

A series of BODIPY-based AIEgens (QB1–QB5 and Bis-QB) containing 2-(2-hydroxyphenyl)­quinazoline have been synthesized and thoroughly characterized. Photophysical properties of these compounds in solution and the aggregated state have been meticulously investigated and fine-tuned via structural modifications. These display green emission (∼530 nm) in solution and bright red emission (600–655 nm) in the aggregated/solid state with increased quantum yield. Crystal structure analyses and spectral studies revealed efficient J-type aggregation in these derivatives. Significant impact of 2-(2-hydroxyphenyl)­quinazoline toward modulating intermolecular interactions and facilitating J-type stacking between BODIPY units has also been established. Moreover, the essential role of excited-state intramolecular proton transfer (ESIPT) in inducing emission in the aggregated state and tuning of ESIPT emission by variation of substituents have been supported by various studies.本研究合成并全面表征了一系列基于氟化硼二吡咯（BODIPY）、包含2-(2-羟基苯基)喹唑啉结构的聚集诱导发光分子（AIEgens）（QB1~QB5与Bis-QB）。针对此类化合物在溶液与聚集态中的光物理性质，本研究通过结构修饰手段开展了细致的探究与精准调控。该类分子在溶液中呈现绿色发射（约530 nm），在聚集/固态下则展现出明亮的红色发射（600~655 nm），且量子产率显著提升。晶体结构分析与光谱研究证实，此类衍生物中存在高效的J型聚集行为。同时明确了2-(2-羟基苯基)喹唑啉对调控分子间相互作用、促进氟化硼二吡咯单元间J型堆叠的关键作用。此外，多项研究证实了激发态分子内质子转移（ESIPT）在诱导聚集态发光中的核心作用，以及通过取代基修饰调节ESIPT发射的可行性。