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Herein, a novel strategy was proposed for identifying carbon monoxide (CO), which plays a crucial part in living systems. For the first time, we have managed to design, synthesize, and characterize successfully this new Cu2+-assisted fluorescent probe (DPHP) in detecting CO. Compared with the commonly adopted Pd0-mediated Tsuji–Trost reaction recognition method, such a new strategy did not engage costly palladium (II) salt and generated no leaving group, indicating a satisfactory anti-interference ability. The recognition mechanism was confirmed by IR, 1H NMR titration, HR-MS, cyclic voltammetry, X-ray photoelectron spectroscopy, electron paramagnetic resonance, and optical properties. Surprisingly, it was found that the new method achieved high selectivity and rapid identification of CO with a lower limit of detection (1.7 × 10–8M). More intriguingly, it could recognize endogenous and exogenous CO in HeLa cells. The cytotoxicity of this new method was so low that it allowed the detection of CO in mice and zebrafish. Basically, our results trigger a novel viewpoint of rationally designing and synthesizing advanced materials for CO detection with unique features, impelling new research in detection chemistry.

Fluorescent probes for detection of CN−still have many limitations, such as small Stokes shift, irreversible, and background interference, which hamper their applications for on‐site detection and bioimaging of CN−. In this work, we design a new CN−‐activatable fluorescent probe (named AHMM) containing an ESIPT (excited‐state intramolecular proton transfer) and hydrogen bond features, which show a large Stokes shift (225 nm) and molecular structural reversible detection. The probe AHMM exhibits an excellent selectivity for CN−without any interference from other anions in aqueous DMSO system. Furthermore, the mechanism of the interaction of AHMM with CN−is concluded by various experiments. The limit of detection of AHMM for CN−is calculated as low as 4.47 × 10−8M, lower than the concentration of CN−deemed acceptable by WHO (World Health Organization). AHMM can recognize CN−in tap water quantitatively and on‐site by a smartphone APP. Moreover, food samples such as almond and cassava including CN−are visualized by fluorescence imaging. In addition, the probe shows practical applications of CN−imaging in cells and mice. This concept can be applied for designing multifunctional fluorescent probes with ESIPT and reversible characteristics for detection of CN−. Cyanide ions (CN−) are highly toxic, and achieving efficient and accurate detection of them is of great importance to maintain life safety. In this paper, the authors design and synthesize a fluorescent probe with ESIPT properties, which can achieve sensitive and selective detection of CN−. Also, the probe is applied to the imaging of CN−in food, cancer cells, and mice in a physiological environment.

By applying an indirect strategy, a new copper (II) complex of a thiosemicarbazone Lhas been successfully developed as a colorimetric chemosensor for the sensitive detection of mercury (II) ions. In the presence of copper (II) ions, the colorless solution of Lbecame yellow; however, upon the addition of traces of mercury (II) ions, the yellow color faded to colorless immediately. Other ions, including Fe3+, Ag+, Ca2+, Zn2+, Pb2+, Cd2+, Ni2+, Co2+, Cr3+and Mg2+had a negligible influence on the probe behavior. The detection limits were 5.0×10−6M and 3.0×10−7M of Hg2+using the visual color changes and UV-vis changes respectively. Test strips based on Cu-Lwere fabricated, which could act as a convenient and efficient Hg2+test kits.