Studies On The Preparation And Properties Of Calixarene Liquid Crystals And Calixarene(Pillararene)-Hybeid Carbon Nanomaterials

Macrocyclic chemistry is an important branch of functional organic molecules.The development of calixarene and pillararene has greatly enriched the research of macrocyclic chemistry,and continuously promoted the rapid development of organic supramolecular chemistry.With the rapid development of liquid crystal materials,the synthesis of host-guest supramolecular liquid crystal system has drawn widespread attention.In particular,the synthesis of discotic columnar liquid crystal with a wide range of mesogenic temperatures,stable and highly ordered liquid crystalline phases is the hot studying field now.On the other hand,carbon nanomaterials are the most active and widely used nanomaterials in the past decade.The carbon nanocomposite materials possess the synergistic effects among its components and show the special function which is obviously superior to the parent building blocks.Therefore,the preparation of the supramolecular carbon nanocomposite has become a new research field,attracting extensive attention of many scholars over the world..In this thesis,calixarene and pillarareneare used as the research platform to combine with liquid crystal materials,carbon nanomaterials,click reaction,or supramolecular polymers,which can be divided into the following five parts.PART 1:The novel calixarene-triphenylene derivatives(5a and 5b)with 1,3-cone conformations were synthesized via click chemistry..The liquid crystalline behaviors of compounds 5a and 5b before and after complexation with silver/sodium metal ions were studied by using polarized light microscopy(POM),differential scanning calorimetry(DSC)and X-ray diffraction(XRD)techniques.The results suggested that the pure compounds(5a and 5b)showed the liquid crystalline behaviors,with triphenylene as a column and calixarene as a side chain..However,the liquid crystalline properties disappeared when the compounds 5a and 5b were complexed with sodium/silver cations.This research innovatively combined the liquid crystalline properties with the guest recognition performance,and found that the liquid crystalline behavior of triphenylene-calixarene can be tuneed by guest ion recognition.This research established a new strategy to develop the supramolecular liquid crystal and study the transformation behaviors of the liquid crystal adjusted by guest recognition.PART 2:The novel calixarene-modified multi-walled carbon nanotubes composites were designed and synthesized by the bridging of covalent bonds.The adsorption properties for the dyes over these composites were systematically investigated by kinetics and thermodynamics.It was found that the composite has good adsorption properties for four dyes of Orange G(OG),Bright Spring Red 5R(BP),Neutral Red(NR),and Methylene Blue(MB).The adsorption process was spontaneous and exothermic,and it followed the quasi-second-order kinetic equation and conformed to the basic trend of the Langmuir adsorption isotherm.PART 3:Based on the covalent bonds,calix[4]arene,thiacalix[4]arene,and calix[6]arene were grafted onto the graphene surface to obtain three examples of calixarene-graphene composites,respectively.They were loaded onto the surface of glassy carbon electrode,and their electrochemical response to bioactive molecules were systematically studied by cyclic voltammetry and differential pulse voltammetry.The influence of cavity size on host-guest inclusion capacity was discussed.The results indicated that the molecular recognition mechanism between the host and the guest was related to the size of the cavity of the host molecule as well as the geometry and size of the guest molecule.Additionally,the composites had good electrochemical selectivity for dopamine.PART 4:A graphene-pillararene composite material was obtained by covalently bonding pillararene to graphene surface via "click chemistry".The results suggested that triazole ring could expand the conjugated region of the system,and the synergistic and additive effects of the interaction between graphene and pillararene were observed among the whole supramolecular system.Cyclic voltammetry and differential pulse voltammetry were used to systematically study the electrochemical response of glassy carbon electrode modified with the composite to bioactive molecules.The results indicated that the composites also had good electrochemical selectivity for dopamine.PART 5:The cross-linked covalent pillararene polymers was designed and prepared based on"click chemistry".The polymers was used to modify carbon electrodes and their recognition performance of bioactive molecules was examined.The results showed that the inclusion ability of host for guest might be influenced by the molecular size of the host and the guest as well as the charge properties of the guest molecules.This pillararene polymer had good electrochemical recognition ability for both dopamine and methylene blue.