A colorimetric boronic acid based sensing ensemble for carboxy and phospho sugars

A cadmium-centered tris-boronic acid receptor was synthesized, and its binding properties toward various anionic sugars were determined. This receptor shows high affinity for different anionic sugars, especially gluconic acid, which has an association constant near similar to 10(7) M-1 at neutral pH. Further, using an indicator displacement assay, a color change of pyrocatechol violet was observed upon addition of anionic sugars. This colorimetric test was used as a facile screening technique to qualitatively analyze guest affinities.