Abstract The fluorescent behaviors and reaction mechanism of 10-hydroxybenzo[h]quinolone (HBQ) on the detection of phenylboronic acid (PBA) have been theoretical studied. The potential curves scan of HBQ in the first single (S1) excited state indicates that the enol form transfers to keto form without any energy barrier. This enol→keto transfer is induced by excited state intramolecular proton transfer (ESIPT) in the S1 state, which occurs in 50 fs with fluorescence emission located at 615 nm. The fluorescence peak of hydrogen bonded HBQ-PBA blue-shifts about 25 nm compared to monomer HBQ dues to the formation of intermolecular hydrogen bond. Thereafter the intermolecular hydrogen bond interrupts the ESIPT and forms reaction products of benzo[h]quinolin-10-yl hydrogen phenylboronate (BQHP) and water. The result of nonadiabatic dynamics indicates that the internal conversion of BQHP complex is forbidden and the fluorescence emission is the main decay pathway. The BQHP exists a fluorescence emission located at 564 nm (S1), which blue-shifts about 50 nm compared with that of intermediate of HBQ-PBA. This work provides a reasonable mechanism of HBQ on the detection of phenylboronic acid.

中文翻译：

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10-羟基苯并[h]喹诺酮对苯硼酸检测的荧光行为及反应机理

摘要 理论研究了10-羟基苯并[h]喹诺酮(HBQ)检测苯基硼酸(PBA)的荧光行为和反应机理。HBQ 在第一个单 (S1) 激发态的电位曲线扫描表明烯醇形式转移到酮形式而没有任何能垒。这种烯醇→酮转移是由处于 S1 状态的激发态分子内质子转移 (ESIPT) 诱导的，其发生在 50 fs 内，荧光发射位于 615 nm。由于分子间氢键的形成，与单体 HBQ 相比，氢键合 HBQ-PBA 的荧光峰蓝移约 25 nm。此后，分子间氢键中断 ESIPT 并形成苯并 [h] 喹啉-10-基苯硼酸氢盐 (BQHP) 和水的反应产物。非绝热动力学结果表明，BQHP配合物的内转化是被禁止的，荧光发射是主要的衰变途径。BQHP 存在位于 564 nm (S1) 的荧光发射，与 HBQ-PBA 中间体相比，其蓝移约 50 nm。该工作为HBQ检测苯硼酸提供了合理的机理。