Synthesis And Properties Of Receptor Recognition For Cyanide

It is well known that CN– is one of the high toxicity anions which is great harmful in biology and environment.The cyanide ion can influence internal secretion,metabolic system in our bodies when people inhale it,in addtion including eyes,blood vessel,central nervous system,heart,and so on,leading to vomit,convulsion,even die.However the cyanide ion is wildly used in the synthesis of organic compounds,metallurgy,electroplate and other industries.So it is very important to design easy,highly selective and sensitive chemosensors for detecting CN–.In view of this,we designed and synthesized several sensors,which could selectively detect cyanide ion.So,we studied its ion recognition performance by some spectrum technologies.The paper including the following four parts:Chapter one:IntroductionThis chapter introduces the mechanism and research value of ions recognition,and the meaning of cyanide recognition.It mainly elaborated the current situation of cyanide anion recognition.And we focus on the following six types of cyanide sensors:(1)deprotonation based ion sensors;(2)hydrogen bonds based ion sensors;(3)addition based ionsensors;(4)metathesis with the atom complexes based sensors;(5)coordination with the atom complexes based sensors;(6)other recognition mechanism.Chapter two: Synthesis and properties of a based sensor for CN– based on salicylaldehyde hydrazone groupIn this chapter,we have designed and synthesized a new,simple,selective chemosensor S1 with diphenyl diketone and salicylaldehyde hydrazone for detectin g CN-.When solutions of other anions such as F-,Cl-,Br-,I-,AcO-,H2PO4-,HSO4-,ClO4-and SCN– were gradually added to the host solution,only the addition of cyanide displayed noticeable color changes from colorless to yellow could be distinguished by naked eyes and showed a bathochromic-shift in UV–vis spectra.In the fluorescence spectra,when CN-was added to the solution,chemosensor produced a significant enhancement of fluorescence intensity,and other anions did not cause any significant changes in the fluorescence color and emission intensity.The data of single crystal indicated the existence of hydrogen bonding.The mechanism of this process was verified by spectroscopic methods including 1H NMR,and mass spectrometry.The addition of cyanide generated deprotonation of-NH and-OH causing the break of the hydrogen bonding.The detection limit on fluorescence response of the sensor to CN-is down to 6.17 × 10-8 mol/L.Test strips based on S1 were obtain,which could be used as a convenient and efficient CN-test kit to detect CN-in aqueous solution.Chapter three: Synthesis and properties of CN– chemosensor based on isoniazide groupIn this work,we have designed and synthesized a simple chemosensor S2 based on the acylhydrazone group as binding site.In the H2O/DMSO(3:7,v/v)solution,the sensor could effectively,rapidly detect CN– by fluorescence and colorimetric dual channel.The gradual addition of cyanide anion displayed expected color change from pale yellow to yellow,and the rendered a remarkable “turn-on” fluorescence response.The other anions such as F-,Cl-,Br-,I-,AcO-,H2PO4-,HSO4-,ClO4-and SCN– revealed a negligible change in the colors and spectra.The detection limit on fluorescence response of the sensor to CN– is down to 5.12×10–8 mol/L,which are far lower than the WHO guideline of 1.9×10-6 mol/L.The 1H NMR titration and Job plot was implemented,demonstrating a 2:1 stoichiometry.The detection can work well in the pH range 9.0–13.0.Test strips based on S2 were obtained,which could be used as a convenient and efficient CN– test kit to detect CN– in aqueous solution.Chapter four: Synthesis and properties of CN– chemosensor based on benzothiazole group.In this work,we have designed and synthesized a onium salt compound S3 based on benzothiazole group.The anions recognition experiments were performed according to the UV–vis and fluorescence spectrum.The results indicated that the highly selective and sensitive sensor molecular could recognize the CN– in DMSO/H2O(3:2,v/v),which showed colorimetric and fluorescence turn-on response.This response was not interfered by other anions such as F-,Cl-,Br-,I-,AcO-,H2PO4-,HSO4-,ClO4-and SCN–.1H NMR and mass spectrometry showed the the spectrum changes were caused by nucleophilic reaction mechanism.In addition,test strips based on S3 were obtained,which could be used as a potential application value to observe the changes bynaked-eyes and UV-vis lamp after adding CN–.