Thiol–Ene\nClick Synthesis of Phenylboronic Acid-Functionalized Covalent Organic\nFramework for Selective Catechol Removal from Aqueous Medium

Abstract

We report a thiol–ene click strategy for the preparation\nof a novel phenylboronic acid-functionalized covalent organic framework\n(COF) for selective removal of catechol in aqueous solution. Vinyl-functionalized\n2,5-diallyloxyterephthalaldehyde (Da-V) was prepared as a building\nligand. Da-V was then condensed with 1,3,5-tris­(4-aminophenyl)­benzene\n(Tab) to give a vinyl-functionalized COF DhaTab-V. Subsequently, 4-mercaptophenylboronic\nacid (4-MPBA) was covalently linked on DhaTab-V via thiol–ene\nclick reaction to give phenylboronic acid-functionalized COF DhaTab-PBA.\nThe adsorption isotherms, energetics and kinetics, and reusability\nof DhaTab-PBA for the adsorption and removal of catechol from aqueous\nsolution were investigated in detail. This phenylboronic acid-functionalized\nCOF is promising as sorbent for selective removal of catechol from\naqueous medium with large adsorption capacity and good reusability.