A novel carbazole-based fluorometric and colorimetric sensor for the highly sensitive and specific detection of Cu 2+ in aqueous solution.

Based on the typical Suzuki coupling reaction and Schiff base reaction, a novel fluorescent molecular PCBW is synthesized and applied as a fluorescence and colorimetric sensor to detect Cu 2+ in aqueous solution. The PCBW sensor presents the aggregation-caused quenching (ACQ) effect and at 1 × 10 -5 mol L -1 it emits the strongest turquoise fluorescence in the DMSO-H 2 O system ( f w = 40%). The sensor exhibits a 'turn-off' fluorescent characteristic by adding Cu 2+ , and its fluorescent intensity shows a reliable linear relationship with the Cu 2+ concentration in the range of 0-6 × 10 -6 mol L -1 , with a detection limit of 1.19 × 10 -8 mol L -1 . Meanwhile, the PCBW sensor also exhibits the colorimetric sensing from colorless to light yellow. The sensor has good selectivity and anti-interference and its pH application range can be extended from 5 to 10. The intramolecular charge transfer (ICT) is speculated as the main fluorescence mechanism of PCBW. In addition, the sensor presents good reusability and is practicable to detect Cu 2+ in diverse aqueous samples.