A novel thiourea‐based fluorescent turn‐on sensor for rapidly detecting hypochlorite through a desulfurization reaction

Abstract Excess hypochlorite (ClO − ) is harmful to living organisms and can cause various oxidative diseases in the human body. Owing to the toxicity of ClO − , the development of efficient fluorescence sensors to track ClO − is necessary. In this work, we report a novel thiourea‐based fluorescent turn‐on sensor 1‐(9‐ethyl‐9 H ‐carbazol‐3‐yl)‐3‐(naphthalen‐1‐yl)thiourea ( ECNT ) for recognizing ClO − . ECNT can detect ClO − with high selectivity, relatively low interference with other analytes, and a significantly fast response time (<1 s) through a desulfurization reaction. The detection limit of ECNT for ClO − is calculated as 5.59 μM. Of note, ECNT is a chemosensor that reacts the fastest with ClO − among the reported thiourea‐based fluorescence turn‐on sensors for detecting ClO − . The response mechanism of ECNT to ClO − is demonstrated through 1 H NMR titration, ESI mass, and density functional theory calculations.