Highly sensitive fluorescent triarylimidazole derivatives for sensing of 2,4,6-trinitrophenol in aqueous solution and its application for actual environment detection

Two highly sensitive fluorescent triarylimidazole derivatives were synthesized by modifying imidazole with coumarin and large conjugate rigid plane structure. XM-F and XM-L emitted bright yellow-green fluorescent light. Their intense conjugation system generated strong π-π electrostatic interactions with TNP, accompanied by the formation of hydrogen bonds to achieve rapid detection of TNP within 25 s. The detection limits were as low as 0.049 μM and 0.071 μM, respectively. Probes had been successfully applied to rapid detection of TNP in real water samples and manufactured into portable fluorescent test strips. In view of excellent performance of XM-F, it was used to achieve real-time, portable, on-site quantitative detection of TNP by a colorimeter and a smartphone platform. In addition, XM-F also successfully processed into probe-coated TLC plates for efficient detection of fingerprints contaminated with TNP.

A new "on-off-on" fluorescent probe containing triarylimidazole chromophore to sequentially detect copper and sulfide ions

A novel compound TPI-H containing triphenylimidazole chromophore is synthesized and employed as fluorescent probe for sequential detection of Cu²⁺ and S^2-. With three binding sites in its molecular structure, TPI-H exhibits highly selective binding towards Cu²⁺ and results in an apparent fluorescence "on-off" behavior. Fluorescence intensity is linear with the Cu²⁺ concentration, and the detection limit can be down to 8.7nM. Furthermore, the in-situ generated ensemble between TPI-H and Cu²⁺ (TPI-H-Cu(II)) can be used to detect S^2- with a low detection limit of 15.6nM through Cu²⁺ displacement method. In addition, the potential utility of the probe for the detection of Cu²⁺ and further S^2- in biological system is investigated by cell imaging.