Greg Springsteen

A detailed examination of boronic acid–diol complexation

Abstract Boronic acids bind with compounds containing diol moieties with high affinity through reversible boronate formation. However, the conditions that foster tight binding between the diol and the boronic acid are not well understood. Also, due to the multiple ionic states of both the boronic acid and boronate ester, the equilibrium constants reported in the literature have not always been strictly defined, and therefore there is a lack of ‘comparability’ between the reported values. To address these issues, we have developed a method for examining boronate ester stability using the fluorescent reporter Alizarin Red S. We have used this system to determine the binding constants of a series of diols, and as a basis from which to derive a number of relationships that correlate the various equilibrium constants in the literature.

A novel type of fluorescent boronic acid that shows large fluorescence intensity changes upon binding with a carbohydrate in aqueous solution at physiological pH

In this paper we report 8-quinolineboronic acid as a novel type of fluorescent probe for carbohydrates. This boronic acid responds to the binding of a carbohydrate with over 40-fold increases in fluorescence intensity and shows optimal fluorescence change at physiological pH in aqueous solution.

Alizarin Red S. as a general optical reporter for studying the binding of boronic acids with carbohydrates

Alizarin Red S. displays a dramatic change in fluorescence intensity and color in response to the binding of a boronic acid and can be used as a general reporter for studying carbohydrate-boronic acid interactions, both quantitatively and qualitatively.

Catechol pendant polystyrene for solid-phase synthesis

A catechol pendant polystyrene polymer was prepared from the Merrifield resin via a convenient procedure with high-density loading. Due to the high affinity binding between catechol and boronic acid, the polymer resin readily captures boronic acid compounds. The feasibility of using immobilized catechol to capture boronic acid products for purification and solid-phase transformation was demonstrated. Moreover, the immobilized catechol was also used for the preparation of resin-bound catecholborane, which can be used as a solid-phase amidation reagent.

The first fluorescent sensor for boronic and boric acids with sensitivity at sub-micromolar concentrations

An anthracene-based PET sensor which uses a diethanolamine recognition site is selective for boronic and boric acids, showing up to a 19-fold fluorescent intensity enhancement upon binding.