Shenzhen Grubbs Institute, Guangdong Provincial Key Laboratory of Catalysis, Department of Chemistry, Southern University of Science and Technology (SUSTech), Xueyuan Blvd 1088, Shenzhen, 518055, China.
Angew Chem Int Ed Engl. 2021 Jan 25;60(4):1929-1935. doi: 10.1002/anie.202012467. Epub 2020 Nov 24.
Buried salt bridges widely exist in protein structures but are rarely used in synthetic systems for molecular recognition in water. By mimicking the binding pocket of bioreceptors, we designed and synthesized a pair of endo-functionalized macrocyclic hosts with secondary ammonium groups in a hydrophobic cavity. We found that these macrocycles are able to selectively recognize carboxylic acids in water through salt bridges and the hydrophobic effect. Moreover, it was demonstrated that these macrocyclic receptors can be used in circular-dichroism-based optical chirality sensing of chiral carboxylic acids and fluorescent sensing of phenylpyruvic acid-a biomarker for phenylketonuria. This research showcases that buried salt bridges can be effectively used by endo-functionalized macrocyclic hosts for molecular recognition in water, where solvent screening on polar noncovalent interactions is high.
埋在蛋白质结构中的盐桥广泛存在，但在水相中的分子识别中很少被用于合成体系。通过模拟生物受体的结合口袋，我们设计并合成了一对具有内功能化的大环主体，其在疏水性空腔中具有季铵基团。我们发现这些大环主体能够通过盐桥和疏水作用选择性地识别水中的羧酸。此外，还证明了这些大环受体可用于基于圆二色性的手性羧酸光学手性传感和苯丙酮酸（苯丙酮尿症的生物标志物）的荧光传感。这项研究表明，埋在内部的盐桥可被内功能化的大环主体有效地用于水相中的分子识别，在水相中，极性非共价相互作用的溶剂筛选非常高。
