Synthesis Of Functionalized Pillar[5]Arene And Their Modification And Application To Gold And Silver Nanoparticles

Pillar[5]arene was successfully synthesized in 2008 for the first time,it has attracted much attention due to their unique molecular structure and recognition properties.As the fourth generation of macrocyclic supramolecular compounds,pillar[5]arene has good application in host-guest recognition,self-assembly,drug delivery and release,etc.When it was used in Catalysis,Raman,Electrochemistry,the material s propertities can be improved obviously.In this paper,we have synthesized two types of pillar[5]arene and used them as the capping agent to modify the gold and silver nanaoparticles,then explored the application of the pillar[5]arene-modified nanaoparticles in Raman and Modified electrodes.The work was systematic developed and mainly divided into the following three aspects:1.The synthesis of Amphiphilic pillar[5]arene and the preliminary application for modifying gold nanoparticlesFirstly,Amphiphilic pillar[5]arene(AP5)was synthesized according to the modified literature method.Then,the as-prepared AP5 were used as protective agents to prepare gold nanoparticles(AuNPs)by the ascorbic acid(AA)as reducing agents.In order to get the insight into the AP5 concentration-dependent effect on as-prepared gold nanoparticles,the concentration of AP5 was changed during this process.It is found that ratio(AP5/HAuCj4)-dependent experiments were conducted,demonstrating gold nanoparticles with uniform morphology and good dispersion could be prepared at the ratio of AP5/HAuCl4 is 30:l(NaBH4 as reducing reagent).In order to investigate the symmetrically impact of reducing agents,ratio,concentration on the as-prepared gold nanoparticles,ascorbic acid(AA)was used to replace NaBH4 as a reducing agent to monitor the reaction process.It is found that the well-dispersed gold nanoparticles can be formed at the ratio of AA and HAuCl4 is 1:1.Subsequently,the as-prepared AuNPs was applied to the Raman-assisted detection field,about acetaminophen and preliminary results were provided in this part.2.Carboxylated-pillar[5]arene modified-silver nanaoparticles to the Raman-assisted detection of Amino acidBased on the first part,in order to get more interesting results,we try to do something change on the pillar[5]arene structure and then find new application of pillar[5]arene.Thus,carboxylated-pillar[5]arene(CP5)was synthesized.The host-guest interaction between CP5 and a series amino acids were studied.It is found that only Tyr shows the interaction with CP5,which demonstrated by UV-vis,fluorescence,and NMR.Then,CP5 was used as modified agent,and NaBH4 was used as a reducing agent,silver nanoparticles(AgNPs)could be prepared in this condition.Well-defined silver nanoparticle with good dispersive properties could be obtained at the ratio of CP5/AgNO3 was 1:1.Based on above results,as-prepared CP5-AgNPs was applied for the detecting Tyr by Raman enhancing technology,the detect limit is 1.0 × 10-5 M.3.Carboxylated-pillar[5]arene modified silver nanoparticles functioned GO to the detection of Paraquat by Electrochemistry.Paraquat(PQ)is a widely used water-soluble herbicide in our daily life.Once it was eaten by mistake,it is harmful to human.Thus,it is particularly important to analyze and detect PQ in the environment.Benefit from the cavity size of pillar,pillar[5]arene and paraquat have strong host-guest recognition,so pillar[5]arene and their composites can be used to analyze and detect paraquat.Here,firstly,the carboxylated pillar[5]arene(CP5)modified silver nanoparticles were used as the substrates for Raman enhanced detection of paraquat.The experimental results showed that the detection limit of paraquat was 1.0×10-5 M based on CP5-AgNPs.In order to broaden the detection range of paraquat and improve the detection limit and sensitivity,CP5-AgNPs and graphene oxide(GO)were combined to prepare ternary composite CP5-AgNPs/GO.Subsequently,the composites were characterized by Transmission electron microscope(TEM),Fourier transform infrared spectroscopy(IR)and AC impedance.It was proved that CP5-AgNPs were modified on GO surface by our experiments.Thus,CP5-AgNPs/GO modified glassy carbon electrode was further constructed.Cyclic voltammetry and pulse voltammetry were used to detect PQ.The optimum pH of modified electrode is 10.0,the detection range is 1.0 ×10-8?1.0 × 10.5 M,2.0 × 10-5?7.0×10-5 M,and the detection sensitivity is as high as 78.8 mA mmol-1 L cm-2.The synergistic catalysis of AgNPs and GO,as well as the host-guest recognition and enrichment of CP5 on paraquat,improving the detection range and detection limit of the modified electrode remarkably.