Chemical Sensor To Indentify Hg²⁺ Is Generated In Wide PH And Based On The High Quantum Yield

Chemical sensors are a class devices of converting chemical information intouseful analytical signal, generally based on the principle of molecular recognition.Molecular recognition is the core of supramolecular chemistry research, which haddivided into anion recognition, cationic and neutral molecular recognition. Mercurypollution always has threaten human health, and in the past few decades, more andmore people began to take attention into the studies of Hg²⁺recognition. The designof supramolecular. Sensing process had completed by sensor molecules and Hg²⁺through the role of the non-covalent bond, such as electrostatic interactions,coordination effect, hydrogen bonding, etc. But since the interaction of thisnon-covalent is often reversible, the selectivity of the system is not high. The reactivechemical sensor worked by detecting the change of fluorescence or the color of thesystem due to the irreversible reactions occurring between the sensor elements and theobject being detected. Obviously, because of advantages such as high selectivity andhigh sensitivity caused by the high stability of the system before and after reaction.,high selectivity and high sensitivity, etc. So the chemical sensors receives more andmore attention of domestic and foreign researchers.The first chapter is the introduction. After introduceing the prospects of thedevelopment and application of chemical sensors, it focuses on the broad applicationprospects of reaction-based chemosensor in the field of environmental monitoring andlife sciences. This review focuses on the latest reported reaction-based sensors foranions, cations and neutral molecules in recent years. The mechanism of sensing andinteresting results are summarized. Reaction-based chemosensor system has beenattracted consid erable attentions due to its high selectivity and sensi-tivity towardssubstrates.More and more attention is contributed to the development ofanalytespecific Reaction-based opitical chemosensors.At last, the progress that hasbeen achieved for the reaction-based opitical chemosensors of Hg²⁺is reviewed.Thispaper follows a classification of the sensing systems based on chemical reactions.Itcomprises of mercury-promoted desulfurization and thiol elimination reactions， mercury-promoted intramolecular cyclization by desulfhydrylation，oxymercuration，mercuration reaction，etc. Contrast supramolecular chemistry sensing Hg²⁺sensors,sensing of Hg²⁺reaction-based chemosensors have stability, loyal, sensitivity, simpleand practical, and many other advantages.In second chapter, on the basis of reviewing the relevant literature, takenp-methoxybenzaldehyde as raw material, we had synthesized ring-opening ligand Lby a four-step reaction. By characterization of¹H-NMR,¹³C-NMR, the structures ofthe intermediate product and the ligand L were recognized. Experiments show thatwhen the measurement of reaction between the sensor molecule L and Hg²⁺were1:1,the sensor molecule L could have the good identification of Hg²⁺, UV andfluorescence spectra of the sensing system confirmed that it had specific selectivityand high sensitivity, and could avoid interference from other metal ions, in theaqueous phase and within a wide range of pH values （pH=3to11） the sensor canalso be good foridentification of Hg²⁺.The third chapter is about the synthesis of several functionalized long-chaincarboxyl group-containing organic ligands, the structures of the intermediate productand the ligand product recognized by¹H-NMR characterization. Since thecoordination of these organic ligands and metal encountered problems, it can not beused as predetermined idea about the research of Hg²⁺sensing.