A turn-on fluorescent sensor for Al3+ based on a crown ether-bridged biscyanostilbene carboxylic derivative

As Al 3+ is an important ion in industry and daily life, the fluorescence sensor with high sensing selectivity and sensitivity for Al 3+ in rapid, simple and in-situ way was always anticipated. In this work, a “turn-on” fluorescence sensor ( CBC ) based on a crown ether-bridged biscyanostilbene carboxylic derivative exhibited excellent fluorescence response for Al 3+ with obvious fluorescence change from dark blue to bright blue-green color. The high sensing selectivity for Al 3+ was observed among 28 kinds of metallic cations and anions. The detecting limitation was as low as 1.68 × 10 −8  M. The sensing mechanism was proposed as that Al 3+ was bound by two carboxyl groups, resulting in the rotating restriction of aromatic groups and strong fluorescence. This sensing ability of CBC for Al 3+ was evaluated by TLC analysis, stamp experiment and simulated water samples, suggesting the excellent application potential on simple, rapid and in-situ detection of Al 3+ in real environments.