A remarkable divergent fluorescence response to epimeric monosaccharides by an isoquinoline-derived diboronate

Herein we report a new boronic acid fluorescent sensor based on 4-isoquinolineboronic acid that has a fluorescent divergent response biologically relevant monosaccharides, glucose and galactose. By analyzing the interactions of this sensor with several alternate sugar forms we have been able to determine how the boronic acid selects diols for binding and how such a molecule could have a positive and negative fluorescent response to two very similar hexoses.