Design, Preparation And Properties Of Organic Fluorescent Sensor Based On The Mechanism Of ICT

Fluorescent chemosensors have a broad prospects in the detection field due to itsrapid identification, high sensitivity, good selectivity and simple synthesis process. Inthis paper, based on the mechanism of ICT, we synthesisd a variety of fluorescentchemosensors for the detection of cyanide and hydrazine using the phenothiazines andanthracene fluorophores. All the spectral properties and biological applications werestudied. TD-DFT calculations suggested the sensing mechanism too. The maincontents are as follows.1．A new high selective and sensitive fluorescent sensor for the detectionof cyanide was developed based on the nucleophilic attack of CN-with a colorchange from purple to colourless. Phc was highly reactive and selective to CN-,with a short responding time (1min), low detection limit (6.67*108M), huge colorchanging and not bad water-solubility. Moreover, Phc had an excellent biocompatibleability, and can indeed visualize the changes of intracellular cyanid in living cells andliving fish. Up to now, this fluorescence experiment was the first time for the sensorsof cyanide to be used in the living animals. TD-DFT calculations suggested thesensing mechanism.The chemosensor was used for fabrication of test strips thatcan detect cyanide in aqueous samples. We envisage this new sensor an extensiveapplication in tracing and adsorbing CN-in the future work.2．A new high selective and sensitive fluorescent sensor for the detection ofcyanide-Anc was developed based on the conjugated of anthracene and hemicyanine.By the nucleophilic attacking of CN-to the indolenium C-2atom of the sensor, theICT progress was blocked with color changed and fluorescence enhanced, and thedetection limit was5.885*108M. The live cell fluorescent experiments demonstratedthe value of the sensor in tracing the CN-in biological systems. Short responding time (less than1second) and excellent water-soluble ability (only20%organic solventsneeded in the detection) provided a broader application prospect in the practicalapplication. The sensing mechanism was well rationalized with the aid of TD-DFT(time-dependent density functional theory) calculations.3．Hydrazine as a very important industrial chemical exhibits a hightoxicity to the human beings. We here developed a new ICT-based fluorescencesensor by the reaction between arylidenemalononitrile and phenothiazine with agood solubility in aqueous media. The sensor Phn displayed high sensitivityand selectivity for the hydrazine, with a color change from orange to colorlessfor the―naked-eye‖detection. TD-DFT calculations suggested that thecolorimetric and ratiometric sensing behavior was due to the interrupt of theICT progress by the inducing of hydrazine. Moreover, Phn has an excellentbiocompatible ability, and can indeed visualize the changes of intracellularhydrazine in live cells and especially in live fish. Dipsticks were alsomanufactured for the convenient detection. We expect our sensor a prospect in arange of chemical and biological applications.4．Novel nanofibrous film with the sensor for cyanide was prepared byelectrospinning. The fluorescent film showed high sensitivities for cyanide due to thehigh surface area-to-volume ratio of the nanofibrous film structures. The fluorescencespectra of the nanofibrous film verified the ability of the film for the detection ofcyanide. The huge color-changing ensure this nanomaterials an extensive practicalapplication in the future.