A fluorescent sensor for Cu2+ and Fe3+ based on multiple mechanisms

摘要

A new fluorescent sensor for the selective and sensitive sensing of Cu ~(2+) and Fe ~(3+) based on the rational control of multiple mechanisms has been developed. Sensor L is weakly-fluorescent ( ? = 0.029) due to the CN isomerization and PET process. Upon binding with Cu ~(2+) , the complex L + Cu ~(2+) can give a remarkable fluorescence enhancement ( ? = 0.182) with a limit of detection down to 1.3 × 10 ~(?8) mol L ~(?1) because of both inhibition of the CN isomerization and PET process. However, upon binding with Fe ~(3+) , the original weak fluorescence of L is completely quenched ( ? = 0.002) due to the paramagnetic quenching property. In addition, the complex L + Cu ~(2+) could be further used as a new platform for the ultrasensitive detection of Fe ~(3+) based on the fluorescence “turn-off” response with a limit of detection down to 2.4 × 10 ~(?8) mol L ~(?1) in aqueous solution.