Highly efficient fluorescent sensing for α-hydroxy acids with C3-symmetric boronic acid-based receptors

Two boronic acid-based fluorescent chemosensors in C3 symmetry have been prepared with a facial method. These compounds show remarkable ability to recognize α-hydroxycarboxy acids and sugar acids over most saccharides. The fluorescence intensity of the receptors decreased obviously upon adding the α-hydroxy acids in a pH 8.71 buffer of methanol-water, which can be explained with the internal charge-transfer (ICT) mechanism.