Study On The Preparation Of The Nanocomposites Based On Macrocyclic Surpermolecular Hosts And Their Applications

Over the past few decades,nanomaterials,different from their macro dimensions,have attracted the interest of the scientists in the field of fundamental research and applied research due to their unique physical and chemical properties.At the same time,the macrocyclic hosts is the important basis for the development of supramolecular chemistry.Currently,nanohybrids is the hot topics in nanotechnology.To introduce the macrocyclic hosts to the field of nanomaterials for preparing organic-inorganic nanocomposites and to exploit their new functions and potential applications are of great scientific significance.This thesis bases on the nanohybrids of macrocyclic hosts and carbon,metal,and metallic oxide nanomaterials.The macrocyclic hosts of cyclodextrin,calixarene,and pillararene are grafted to the surface of carbon,metal,and metallic oxide nanomaterials via non-covalent interactions to construct a series of nanohybrids.Subsequently,the integration of macrocyclic hosts and carbon,metal,and metallic oxide nanomaterials was studied for the application in the field of electrochemical sensing,fluorescent sensing,and catalysis.In the first part,(a)in this study,uniform,monodispersed 4.5nm Au NPs were anchored onto carboxylic graphene nanosheets(CGS)using a green approach.The P-CD functionalized Au@CGS(?-CD-Au@CGS)nanohybrid was successfully fabricated by subsequent conjugation of ?-CD with the aid of thiol and carboxyl groups.The nanohybrid was characterized by TEM,FTIR,and TGA.Electrochemical sensing platform was constructed by using the P-CD-Au@CGS nanohybrid.The electrochemical behaviors of hydroquinone(HQ)and ?-nitrophenol(PNP)were studied by the using the sensing platform.Simultaneous determination of HQ and PNP using the electrochemical sensor was conducted.(b)Uniform and monodispersed-5.0 nm Au NPs were anchored on the SiC-NH2 surface via a chemical reduction process by using polyethylene glycol and sodium citrate as dispersant and stabilizing agent.CM-(3-CD was covalently bound on Au@SiC by combining the amine group of SiC-NH2 with the carboxyl group of CM-?-CD with the aid of EDC/NHS coupling agent.SH-P-CD could tightly attach to the surface of Au@SiC by the strong coordinating capability between Au and thiol.The obtained nanohybrid was characterized by TEM,XRD,FTIR,and TGA.By using the obtained ?-CD-Au@SiC-NH2 nanohybrid as electrode material,a novel electrochemical sensing platform was developed for the sensitive determination of tadanafil.The proposed electrochemical sensing platform was successfully used to determine tadalafil in spiked human serum samples.In the second part,(a)p-sulfonated calix[6]arene functionalized reduced graphene oxide(SCX6-RGO)nanohybrid was prepared by a wet-chemical method in aqueous solution and characterized by FTIR,TGA,and Raman.The host-guest interaction between cholesterol and SCX6 was studied by absorbance and fluorescence titration.The SCX6/cholesterol inclusion complex was investigated by molecular modeling calculations,suggesting that hydrogen bonding,electrostatic interactions,and hydrophobic interactions should be the predominant driving forces for the formation of the inclusion complex.A novel electrochemical sensing platform has been developed towards cholesterol detection based on competitive host-guest interaction by selecting methylene blue(MB)and SCX6-RGO as the "reporter pair".Upon the presence of cholesterol to the performed SCX6-RGO.MB complex,the MB molecules are displaced by cholesterol,leading to a "switch off" electrochemical response.The proposed competitive electrochemical sensing platform was successfully used to determine cholesterol in human serum samples,(b)p-sulfonated calix[8]arene functionalized single-walled carbon nanohoms(SCX8-SWCNHs)was prepared by an ultrasonic-assisted method and characterized by TEM,FTIR,TGA,and zeta-potential.The host-guest interaction between aconitine and SCX8 was studied by fluorescence titration.A dual-signalling electrochemical approach has been developed towards aconitine based on competitive host-guest interaction by selecting MB and SCX8-SWCNHs as the "reporter pair".Upon the presence of aconitine to the performed SCX8-SWCNHs· MB complex,the MB molecules are displaced by aconitine.This results in a decreased oxidation peak current of MB and the appearance of an oxidation peak of aconitine.This dual-signalling sensing platform can provide more sensitive target recognition and will have important applications in the sensitive and selective detection of aconitine.In the third part,(a)p-sulfonated calix[6]arene-graphene(SCX6-Gra)nanohybrid was prepared by a wet-chemical method in aqueous solution.The obtained SCX6-Gra nanohybrid was characterized by TEM,FTIR,TGA,AFM,and zeta-potential.The inclusion complex of tadalafil and SCX6 was studied by fluorescence titrations and molecular docking.A competitive fluorescence sensing platform towards tadalafil detection has been developed based on host-guest recognition by selecting rhodamine B(RhB)and p-sulfonated calix[6]arene functionalized graphene(SCX6-Gra)as the"reporter pair".The fluorescence of RhB was quenched by Gra when it was included in the host of SCX6.Upon the presence of tadalafil to the performed SCX6-Gra-RhB complex,the RhB molecules are displaced by tadalafil,leading to a "switch-on"fluorescence signal.The proposed competitive fluorescence sensing platform was successfully used to determine tadalafil in spiked human serum samples,(b)SCX8-RGO was prepared by a green wet-chemical route and characterized by AFM,FTIR,TGA,and zeta-potential.The inclusion complex of SCX8/aconitine was studied by fluorescence titrations,molecular docking,and molecular dynamics simulation,which indicated that the phenyl ester group of the aconitine molecule was included into the SCX8 cavity.And the binding mode analysis demonstrated that the hydrogen bonding interactions,?—? interaction,T shaped ?-? interaction,?-anion interaction,and hydrophobic interaction made the contribution for the formation of such inclusion complex.A novel method for the determination of aconitine through the competitive host-guest interaction between SCX8 and signal probe/target molecules by using SCX8-RGO as a receptor.Three dyes(ST,RhB,BRB)and aconitine were selected as the probe and target molecules,respectively.The formation of SCX8-RGO-ST,SCX8-RGO·RhB,and SCX8-RGO-BRB complexes greatly decreases the fluorescence emission of ST,RhB,and BRB.The aconitine/SCX8 complex possesses a higher binding constant than ST/SCX8,RhB/SCX8,and BRB/SCX8 complexes,thus the dye in the SCX8 cavity can be replaced by aconitine to revert the fluorescence emission of SCX8-RGO·dye,leading to a "switch-on"fluorescence response.The proposed fluorescence sensing platform was successfully used to determine aconitine in human serum samples.In the fourth part,(a)we report a facile and green route for the synthesis of nanostructured MnO2 with morphologies of nanoflakes and nanocluster-aggregates in aqueous solution at room temperate within 30 min without the need for any organic solvent or high temperature via direct reduction of KMnO4 by macrocyclic host p-sulfonated calix[4,6,8]arene.To the best of our knowledge,this is the first time to report that macrocyclic supramolecules are used to mediate and control the synthesis of nanostructured MnO2 nanomaterials.The obtained MnO2 nanomaterial were characterized by TEM,AFM,XRD,EDX,elemental mapping,and XPS.The mechanism for the formation of the MnO2 nanomaterials was speculated.The catalytic activity of the MnO2 nanomaterials toward MB reduction was studied.The results indicated that the MnO2 nanomaterials showed high catalytic activity for the reduction of MB.(b)Water soluble pillar[5]arene(WP5)with ten amino groups(-NH3+)was used to control the synthesis of ultra-small Pd and Pt nanoparticles.At the same time,the Pd and Pt NPs were supported on molybdenum disulfide-carbon nanosphere(MoS2-CNS)to obtain the Pd-MoS2-CNS and Pt-MoS2-CNS nanohybrids.The Pd-MoS2-CNS and Pt-MoS2-CNS nanohybrid were characterized by TEM,XRD,EDX,elemental mapping,and XPS.The catalytic activity of the Pd-MoS2-CNS and Pt-MoS2-CNS nanohybirds toward MB and 4-NP reduction was studied.The results indicated that the Pd-MoS2-CNS and Pt-MoS2-CNS nanocatalysts showed high catalytic activity.In a word,by combining the merits of macrocyclic hosts and nanomaterials,a series of functional nanocomposites based on macrocyclic hosts were prepared.These nanocomposites were used for application in the field of electrochemical/fluorescence sensing and catalysis.The results provide new insights for the preparation and application of nanocomposite.