A New Class of Fluorescent Boronic Acids that Have Extraordinarily High Affinities for Diols in Aqueous Solution at Physiological pH

摘要

The boronic acid group is an important recognition moiety for sensor design. Herein we report a series of isoquinolinylboronic acids that have extraordinarily high affinities for diol-containing compounds at physiological p H. In addition, 5- and 8-isoquinolinylboronic acids also showed fairly high binding affinities with d-glucose (Ka = 42 and 46 M⁻¹, respectively). For the very first time, weak but encouraging binding with cis-cyclohexanediol was found for these boronic acids. Such binding was coupled with significant fluorescence changes. Furthermore, 4- and 6-isoquinolinylboronic acids also showed ability to complex methyl-α-d-glucopyranose (Ka = 3 and 2 M⁻¹, respectively).