A Highly Selective Probe for Real-Time Monitoring of Ethylenediamine with Ratiometric Luminescent and Colorimetric Dual-Mode Responses

Ethylenediamine (EDA), as an important chemical raw material and fine chemical intermediate, has been widely applied in various industries. Real-time monitoring of EDA is highly desirable in daily life due to its potential threat to human health. Herein, we report a molecular probe named 4,4'-(9H-carbazole-3,6-diyl)bis(1-(naphthalen-2-ylmethyl)pyridin-1-ium) iodide (p-N-DPC·I₂) with ratiometric luminescent and colorimetric dual-mode responses toward EDA, endowing a highly sensitive and selective detection method for its real-time monitoring. The experimental and theoretical calculation results revealed that the response mechanism was due to forming a charge transfer (CT) state when p-N-DPC·I₂ met with EDA. In addition, a hydrogel-based sensing chip was developed to achieve the ultrasensitive recognition of EDA vapor with the naked eye at a concentration as low as 10 ppm. This study developed a new probe with ratiometric fluorescent and colorimetric modes to detect EDA both in solution and vapor.