Arresting “Loose Bolt” Internal Conversion from −B(OH)<sub>2</sub> Groups is the Mechanism for Emission Turn-On in <i>ortho</i>-Aminomethylphenylboronic Acid-Based Saccharide Sensors
作者:Xiaolong Sun、Tony D. James、Eric V. Anslyn
DOI:10.1021/jacs.7b12877
日期:2018.2.14
explain the data, we performed a series of experiments to explore the origin of the emission turn-on with several boronic-acid based sensors upon binding fructose. First, we showed that the receptors and their complexes with fructose are solvent-inserted, with no B-N interactions. Second, we verified that the sensors are not aggregated. Third, in pure methanol, that exchanges -B(OH)2 to -B(OMe)2 groups
已经假设了具有附加荧光团的邻氨基甲基苯基硼酸响应水介质中糖类结合的发射开启的不同机制,例如光诱导电子转移 (PET)、“pKa 开关”和解聚。然而,没有一个假设与基于硼酸的传感器的所有数据一致。为了创建一个可以解释数据的统一理论,我们进行了一系列实验,通过结合果糖的几种基于硼酸的传感器来探索发射开启的起源。首先,我们表明受体及其与果糖的复合物是溶剂插入的,没有 BN 相互作用。其次,我们验证了传感器没有聚合。第三,在纯甲醇中,将 -B(OH)2 交换为 -B(OMe)2 基团,我们发现结合果糖后没有荧光反应。我们建议通过减少内部转换机制来实现这一点。为了进一步研究该提议,我们进行了溶剂同位素效应研究。D2O (-B(OH)2 → -B(OD)2) 中探针的荧光在果糖结合时不会改变。众所周知,-OD 振荡器由于其较低的频率振动模式是效率较低的能量接收器。因此,我们的研究表明,调节 -B(OH)2