A Fluorescent Organic Probe for Naked‐Eye Detection of Chloromethanes

An organic fluorescent probe (OFP-TAR) with a propeller-like structure was designed and synthesized. The photoluminescence of OFP-TAR in solution exhibited a significant red shift with the increase of solvent polarity, enabling a transition of fluorescence emission from blue (445 nm) to yellow (540 nm). The organic thin-film materials based on OFP-TAR/PMMA exhibit significant color changes upon exposure to CH₂Cl₂, CHCl₃, and CCl₄, with their maximum fluorescence wavelengths measured at 445, 471, and 494 nm respectively. The device facilitates the visual detection of chloromethanes and is capable of enduring more than 7 cycles of testing. These materials can also be prepared as binary-coded microarray data storage devices or applied in the field of anti-counterfeiting. The quantum yields of guest-loaded crystals CH₂Cl₂@OFP-TAR, CHCl₃@OFP-TAR and CCl₄@OFP-TAR are observed as 19.13 %, 8.79 %, and 0.83 % respectively, which are consistent with the tendency of OFP-TAR in CH₂Cl₂ (47.30 %), CHCl₃ (34.27 %) and CCl₄ (3.10 %). The fluorescence properties of OFP-TAR, OFP-TAR/PMMA, guest-loaded and guest-free crystals provided insights into the special response mechanism of OFP-TAR towards different chloromethanes.