A highly selective turn-on fluorescent chemodosimeter for Cu(2+) through a Cu (2+)-promoted redox reaction.

A highly sensitive and selective photoinduced electron transfer (PET) fluorescence chemodosimeter L for Cu(2+) detection has been synthesized and characterized. This PET chemosensor composed of a butano-tethered electron-riched phenothiazine (Ptz) donor and acridine orange (AO) signalling element. Based on the Cu(2+)-promoted oxidation of Ptz donor, the signalling element AO showed a unique fluorescent turn-on properties, which led to a highly Cu(2+)-specific fluorescent chemodosimeter. A fluorescent enhancement factor over 8-fold can be reached by fully blocking the PET channel with a detection limit down to the 10(-7) M range. Meanwhile, the reversibility of the chemodosimeter L can be realized by the addition of L-cysteine.