Synthesis And Application Of Turn-on Fluorescent Probes For Palladium And Hydrogen Sulfide

Fluorescent probes are a kind of tools that can transfer molecular interaction into fluorescence signals. Due to the excellent optical properties (high quantum yields, good photostability) and biocompatibility, fluorescence methods have been widely applied to biological technique, biochemistry, materials, analytical and environmental chemistry. The main fluorophores used in developing fluorescent probes include benzothiazole, coumarin, rhodamine, cyanine and dansyl. As the development of fluorescence-based imaging techniques, in-situ, real time detection with high spatial discrimination came true. This article focused on the detection of Pd2+ and H2S by using of coumarin, benzothiazole and rhodamine as fluorescence reporters. Detailed as follows:1. The synthesis and optical response of a Pd2+ fluorescent probe based on rhodamine BIn view of the fine affinity of Pd2+ to electron-rich "C=C" conjugation systems, a fluorescent probe RL for Pd2+ was developed here. Rhodamine B was selected as the fluorescence reporter due to its easy preparation and purification, high quantum yield, good water solubility and low toxicity. The fluorescence of rhodamine was set out through Pd2+ induced ring-opening of non-emissive rhodamine. The solution would change from colorless to red. Furthermore, addition of S2" to the red solution could retain the ring-closed probe by forming precipitate PdS. This probe could detect Pd2+ in normal conditions and with high sensitivity (detection limit:23 nM) and good anti-interference performance.2. The synthesis and optical response of a H2S fluorescent probe based on coumarin-benzothiazole structureBy introducing 2,4-dinitrophenyl ether moiety onto coumarin-benzothiazole platform, probe CTN was synthesized for H2S detection. Addition of H2S to the probe solution, a turn-on fluorescence response was detected. What’s more, the solution changed from colorless to yellow. The probe could function under mild conditions and with good selectivity. The detection limit was determined to be 90 nM. Importantly, CTN was nontoxic to cells. The fluorescence imaging of He la cellular H2S was successfully conducted.