Watson Alexander E R, Boyle Paul D, Ragogna Paul J, Gilroy Joe B
Department of Chemistry, The University of Western Ontario London Ontario N6A 5B7 Canada
Surface Science Western London Ontario N6G 0J3 Canada.
Chem Sci. 2024 Dec 26;16(5):2258-2264. doi: 10.1039/d4sc06392a. eCollection 2025 Jan 29.
Fluorophores that respond to external stimuli, such as changes in pH, have utility in bio-imaging and sensing applications. Almost all pH-responsive fluorophores rely on complex syntheses and the use of pH-responsive functional groups that are peripheral to the fluorophore framework. In this work, pH-responsive boron-containing heterocycles based on tridentate acyl pyridylhydrazone ligands were prepared. These non-emissive heterocycles were synthesized in three steps from inexpensive, commercially available reagents without the use of chromatography or air-sensitive reagents. Treatment with acid resulted in protonation of the boron-bound methylamine donor and efficient blue photoluminescence. Experimental and computational analysis revealed that protonation changed the geometric structure of the heterocycles and prevented photoluminescence quenching associated with photoinduced electron transfer. This work demonstrates a new approach for the design of fluorophores with potential applications in biological imaging.
对外部刺激（如pH值变化）有响应的荧光团在生物成像和传感应用中具有实用性。几乎所有对pH响应的荧光团都依赖于复杂的合成方法以及使用位于荧光团骨架外围的pH响应官能团。在这项工作中，制备了基于三齿酰基吡啶腙配体的对pH响应的含硼杂环化合物。这些无发射的杂环化合物由廉价的市售试剂分三步合成，无需使用色谱法或对空气敏感的试剂。用酸处理导致与硼相连的甲胺供体质子化并产生高效的蓝色光致发光。实验和计算分析表明，质子化改变了杂环化合物的几何结构，并防止了与光致电子转移相关的光致发光猝灭。这项工作展示了一种设计荧光团的新方法，该荧光团在生物成像中具有潜在应用。
