A fluorescent and colorimetric chemosensor for dihydrogen phosphate ions based on 2-pyridine-1H-imidazo[4,5-b]phenazine-zinc ensemble

A long wavelength emission fluorescent (600 nm) and colorimetric (from pink to yellow) chemosensor with high selectivity for H2PO4- ions was designed and synthesized according to the twisted intramolecular charge transfer (TICT) mechanism. The sensor was bearing a 2-pyridine-1H-imidazo[4,5b] phenazine and Zn2+ metal complex (S-2-Zn), which shown brilliant fluorescent and colorimetric response for H2PO4- anions in aqueous solution. The detection limit of the sensor toward H2PO4- is 2.4 x 10(-6) M, and other anions, including F-, Cl-, Br-, I-, AcO-, HSO4-, ClO4- and CN- had nearly no influence on the probing behavior. The test strips based on 2-pyridine-1H-imidazo[4,5-b]phenazine and Zn2+ metal complex (S-2-Zn) were fabricated, which could act as a convenient and efficient H2PO4- test kits. (C) 2013 Elsevier B.V. All rights reserved.