A Single-Fluorophore Multicolor Molecular Sensor That Visually Identifies Organic Anions Including Phosphates

Developing fluorescent sensors for small-molecule phosphates offers opportunities in optically detecting biorelevant reactions and events.However,it remains elusive how to identify phosphates from other anions,such as carboxylates and sulfates,because current synthetic phosphate receptors lack selectivity.Here we report the construction of a multicolor fluorescent sensor that can identify phosphates from other analogous anions.The key design principle is to take advantage of the highly sensitive conformation-dependent emissive wavelength of diphenyl-9,14-dihydrodibenzo[a,c]phenazine fluorophores to sense the minor structural differences between phosphates and other anions,for example,sulfates and carboxylates.The effect of structural factors such as spacer length and urea versus thiourea has been investigated by comparing the optical properties and binding affinities with the phosphate receptors.This strategy provides a simple and robust fluorescent sensing solution to optically analyze small-molecule phosphates with antiinterference performance.