Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej, 55, 5230, Odense, Denmark.
Division of Immunotherapy, Oncode Institute, Radboud University Medical Center, 6525 GA, Nijmegen, The Netherlands.
Chemistry. 2022 Feb 16;28(9):e202104044. doi: 10.1002/chem.202104044. Epub 2022 Jan 22.
Boronic acids are Lewis acids that exist in equilibrium with boronate forms in aqueous solution. Here we experimentally and computationally investigated the Lewis acidity of 2,6-diarylphenylboronic acids; specially designed phenylboronic acids that possess two flanking aromatic rings with tunable aromatic character. Hammett analysis of 2,6-diarylphenylboronic acids reveals that their Lewis acidity remains unchanged upon the introduction of EWG/EDG at the distant para position of the flanking aromatic rings. Structural and computational studies demonstrate that polar-π interactions and solvation effects contribute to the stabilization of boronic acids and boronate forms by aromatic rings. Our physical-organic chemistry work highlights that boronic acids and boronates can be stabilized by aromatic systems, leading to an important molecular knowledge for rational design and development of boronic acid-based catalysts and inhibitors of biomedically important proteins.
硼酸是路易斯酸，在水溶液中与硼酸形式处于平衡状态。在这里，我们通过实验和计算研究了 2,6-二芳基苯硼酸的路易斯酸度；特别设计的苯硼酸具有两个侧翼芳香环，具有可调节的芳香特性。2,6-二芳基苯硼酸的哈米特分析表明，在侧翼芳香环的远程对位引入 EWG/EDG 时，其路易斯酸度保持不变。结构和计算研究表明，极性-π 相互作用和溶剂化效应对芳香环稳定硼酸和硼酸酯起到了贡献。我们的物理有机化学研究强调了硼酸和硼酸酯可以被芳香体系稳定，这为基于硼酸的催化剂和生物医学重要蛋白质抑制剂的合理设计和开发提供了重要的分子知识。
