Synthesis And Properties Of Anionic And Cation Recognition Receptors Based On Functionalized Schiff Base Compounds

Anions and cations play an extremely important role in the normal physiological function of the human body.Excessive or small amount of ions will cause different degrees of harm to human body.At the same time,anions and cations are closely related to people's production and life which widely used in electroplating,mining,metallurgy,medicine and pesticide production,causing serious pollution to the environment.Therefore,it is significant to design and synthesize a probe with simple structure,high selectivity,high specificity and high sensitivity for detecting environment,food,medicine and other aspects.In this work,several probe molecules with recognition functions for specific anions and cations were designed and synthesized,and recognition performance was studied in detail.The thesis consists of four parts:Chapter one:IntroductionThe concept and development of supramolecular chemistry,the significance of ion recognition and the latest research progress of ion recognition are introduced.Five types of ion probes are summarized according to the different recognition mechanisms:?1?Deprotonation-type ion probes;?2?Hydrogen bonding type ion probe;?3?Special reaction type ion probe;?4?Coordination ion probe;?5?Ion probes based on other principles.Chapter two:Synthesis and Properties of Double Schiff Base Probe N1 Based on2-Hydroxypyridinecarboxaldehyde GroupIn this chapter,we designed and synthesized a colorimetric and fluorescent chemical probe N1 with a simple Schiff base structure using pyridinaldehyde and o-benzidine as raw materials.It is used for the colorimetric and fluorescent response of cyanide ions in aqueous solutions with high selectivity and high sensitivity.After the addition of CN^-,the color of the probe was observed to change from yellow to colorless by the naked eye;under fluorescent light,the yellow fluorescence was significantly quenched.The minimum detection limit of the probe for CN^-fluorescence response is 4.43×10^-77 mol/L.In addition,we successfully used the probe N1 to qualitatively detect CN^-in bitter almonds.At the same time,the test strip of N1was prepared which can more conveniently and effectively detect CN^-in aqueous solution.Chapter three:Synthesis and Properties of Schiff Base Probe N2 Based on5-nitro-2-hydroxyaniline GroupIn this chapter,a colorimetric and fluorescent dual-channel chemical probe N2 with a simple Schiff base structure was designed and synthesized to identify cyanide ions in aqueous solution with high selectivity and high sensitivity.After the addition of CN^-,the color of the probe was observed to change from colorless to brown by the naked eye;under ultraviolet light,the fluorescence change from colorless to pale yellow.ICT effect between probe N2 and CN^-was confirmed by ¹H NMR titration and the stoichiometric ratio of reaction was 1:2.The minimum detection limit of the probe for CN^-fluorescence response was 4.31×10^-77 mol/L.In addition,we successfully used the probe N2 to qualitatively detect cyanide in bitter almonds.Chapter four:Synthesis and Properties of Double Schiff Base Probe N3 Based on N,N-Diethylamino Salicylaldehyde GroupIn this chapter,we designed and synthesized a new Fe³⁺chemical probe N3 using N,N-diethylaminosalicylaldehyde and o-benzaldehyde which can recognize Fe³⁺in both ultraviolet and fluorescent channels in DMSO/H₂O?7:3,v/v?solution.Moreover,the results of the anti-interference experiment revealed that all potentially competitive cations(Hg²⁺?Ag⁺?Ca²⁺?Cu²⁺?Co²⁺?Ni²⁺?Cd²⁺?Pb²⁺?Zn²⁺?Cr³⁺?Mg²⁺)exerted no or little influence on the UV–vis and fluorescence detection of Fe³⁺.The 1:1 stoichiometry of N3 and Fe³⁺was confirmed by the Job's plot.the IR and MS prove that the coordination of N3 and Fe³⁺caused the change of the ultraviolet and optical properties of the host molecule to reach the purpose of identifying Fe³⁺.In addition,the detection limit of the probe for Fe³⁺recognition was6.97×10^-77 mol/L.Most importantly,test strips containing the host N3 were prepared to quickly determine Fe³⁺in the solution.Based on these advantages,we believe that probe N3has certain potential application value.