Relay recognition of Cu2+ and S2- in water by a simple 2-(2′-aminophenyl)benzimidazole derivatized fluorescent sensor through modulating ESIPT

A new 2-(2'-aminophenyl)benzimidazole (2-APBI) derivatized fluorescent sensor (L) that behaves relay recognition of Cu2+ and S2- in water solution (pH 7.4) has been developed. Sensor L displays excited-state intramolecular proton transfer (ESIPT) featured two emission bands and performs highly selective and sensitive recognition to Cu2+ through two emissions simultaneous quenching. The on-site formed L-Cu2+ complex exhibits excellent selectivity to S2- with fluorescence off-on response via Cu2+ displacement approach, which exerts ESIPT recovery. Thus, through modulation the ESIPT state of sensor I relay recognition of Cu2+ and S2- in water has been achieved. (C) 2013 Elsevier B.V. All rights reserved.