Boron acid complexation reactions with polyols and α-hydroxy carboxylic acids: Equilibria, reaction mechanisms, saccharide recognition

Abstract

Interest in the equilibria and mechanisms of boron acid complexation reactions has increased dramatically in the past few years in part because of the effective use of boron acid complexation chemistry in saccharide recognition. In this study, it is shown that borate complex ions (1:1−) are capable of forming ternary mixed-ligand complexes (1:2−) with polyols over a wide range of pH thereby allowing the possible use of such 1:1− borate complex ions in the recognition of saccharides. From a mechanistic perspective, it is also demonstrated that rate constants for the complexation reactions of borates with polyols correlate with the basicity of the borate anions. Therefore, depending on the specific boron acid, the pattern of reactivity with a particular ligand may be either RB(OH)2>RB(OH)3− or RB(OH)3−>RB(OH)2.