Synthesis And Applications Of A Colorimetric And Fluorescent Probe For Detection Of Cyanide Ion/hydrogen Cyanide

Cyanide is highly toxic,but it is extensively used in the industrial production,such as gold mining,petrochemical industries,electroplating,and metallurgy.Cyanide exists in two forms:cyanide ion and hydrogen cyanide gas.Cyanide anions(CN-)are extremely toxic to physiological systems by inhalation or skin absorption.Cyanide in the bloodstream of humans can bind to the active site of cytochrome oxidase to form a stable complex and subsequent inhibition of the mitochondrial respiratory chain,leading to cytotoxic hypoxia and cellular asphyxiation,and then resulting anaerobic metabolism cases accumulation of lactate in the blood.Finally,the combined effects of hypoxia and lactate acidosis disturb the central nervous systems,leading to respiratory arrest and death.Moreover,hydrogen cyanide(HCN)gas was used in the World War II as a weapon of mass destruction and is categorized as a chemical warfare agent under the class of blood agents(AC).The leakage in industrial production or used as a terrorist attack weapon of cyanide will cause serious damage to the environment and the human body.Therefore,it is very important to develop a rapid and effective method to detect cyanide ion and hydrogen cyanide gas.This article focuses on the designed and synthesis of cyanide/hydrogen cyanide fluorescent probe,more specially:In the chapter 1,we introduced the source and toxicity of cyanide,and summarized the cyanide ion probe designed by our predecessors.At present,the cyanide ion probes are designed based on these four reaction mechanism:1.cyanide ion nucleophilic attack double bond and form C-C bond;2.cyanide ion attack the positive charge boron atom to form a C-B bond;3.cyanide ion deprives the probe hydrogen of the-NH2 or-OH,and the hydrogen proton transfer occurs;4.The strong complexing ability of the cyanide ion and the metal ions is used to seize the metal ions of the probe,and enhance the fluorescence of solutions.In the chapter 2,we designed and synthesized four cyanide ion probes based on the mechanism of intramolecular charge transfer(ICT)with the structure of 6-diethylamino-2-vinyl quinoline.The probe molecules are constructed with quinoline as chromophore,diethylamino as electron donating group and the 2-vinyl substituent as both electron withdrawing group and reaction site.After the nucleophilic addition with CN-at the vinyl ?-carbon,the electron-withdrawing group converts to the pyridine ring,the ICT process becomes weak,and the UV-Vis and fluorescence spectrum of probe molecule changes eventually.Depending on the electron-withdrawing ability of the substituents at the vinyl group,the variation of ICT before and after the reaction are different,that is,the sensing properties are different,and we choose the best one to do further research finally.We verify the reaction mechanism by NMR and mass spectrometry analysis.With the support of the data calculated by Gaussian software,we found that the stronger electron-withdrawing ability of the substituents on the vinyl group,the higher positive charge density of the vinyl ?-carbon,and the stronger reactivity of the reaction.In previously published articles,few probes were used to detect hydrogen cyanide gas.Therefore,in the chapter 3,the chosen probe was loaded in the polymer film for equivalent test and selectivity measurement.These experimental results show that the chosen probe has good potential applications in the detection of cyanide ion and hydrogen cyanide gas.