Construction And Application Of Conjugated Macrocycle Polymers Based On Pillar[5]arene

Porous organic polymers（POPs）represent a series of covalently linked two-dimensional（2D）orthree-dimensional（3D）networks-basednovel macromolecular materials that are fabricated from small organic building blocks through specific organic reactions,and normally possess highly cross-linked frameworks and micropores or mesopores structures.Based on the differences in preparation conditions,connection mechanisms and product structures,POPs could be further classified into crystalline covalent organic frameworks（COFs）,covalent triazine polymers or frameworks（CTPs or CTFs）,amorphous hyper-cross-linked polymers（HCPs）and polymers of intrinsic microporosity（PIMs）,conjugated microporous polymers and porous aromatic frameworks（PAFs）.Benefited from the high specific surface area,physical or chemical stabilities,easily modifiable performance,extensive and various reactants,one could adjust the length and rigidity of their building units as well as various modifications and topology,and apply POPs in various fields including gas adsorption and separation,optoelectronic devices,chemosensors and heterogeneous catalysis.The development and use of supramolecular host compounds are the hot topic in supramolecular chemistry.Crown ethers,cyclodextrins,calixarenes and cucurbiturils are the representative four generation of macrocyclic hosts,and pillararenes are regarded as a relatively new generation of this family.Owing to the modifiable side groups,symmetric?-rich cavities and stably rigid frameworks,pillararenes have gained close attention.The rational functionalization of pillararenes could yield specific rigid building units that could be used to construct metal organic frameworks（MOsF）or POPs based on covalently-linked pillararenes.In this thesis,we used pillararenes to fabricate a novel class of POP materials.Different from the traditional POPs constructed by simple organic molecules,our conjugated frameworks are derived from macrocyclic compounds like pillararenes,therefore we named them conjugated macrocycle polymer（CMP）.CMP could also be endowed with special optical,electronic and catalytic properties through the choice of linker units.The resultant CMPs combined the thermostability,insolubility,ease of fabrication and reusability of traditional POPs with the selectively guest recognition and adsorption properties of macrocyclic hosts.The specific properties of the supramolecular?-rich cavities of pillararenes could also be imparted into the frameworks,leading to novel characteristics and function of the CMP materials.The main research works of this thesis are divided into the following two parts:In the first section,we first constructed a luminescent CMP material（P[5]-TPE-CMP）with strong fluorescence property,from ditriflate functionalized pillar[5]arene and a 1,1,2,2-tetrakis（4-ethynylphenyl）ethylene（TPE）linker through Sonogashira-Hagihara cross-coupling reaction.Significantly,in sharp contrast with the corresponding conjugated microporous polymer without synthetic macrocycles,P[5]-TPE-CMP showed an outstanding stability against photobleaching,large Stokes shifts,and exhibited highly selective cation sensing capability towards Fe³⁺.Meanwhile,its fluorescence could also be sufficiently quenched by 4-amino azobenzene,a frequently used organic dye that has been certified to be carcinogenic,as compared with a group of common organic compounds.This work paves a new way for enhancing the properties of POPs and expanding the POP family through the introduction of supramolecular macrocycles like macrocyclic arenes,and may lead into a broad and far-reaching significance.In the second section,a new CMP,namely DMP[5]-TPP-CMP,was synthesized via the copolymerization of pyrrole and a dibenzaldehyde-functionalized pillar[5]arene.Two representative types of macrocyclic compounds,i.e.,pillararene and porphyrin,were integrated as alternating strut/node components into the skeleton of CMP microparticles with a diameter of ca.10μm.We found that this material possesses excellent thermostability and high resistance to solvents,acids and bases,and could bear with oxidation and the treatment of strong corrosive compounds like BBr₃.CMP microparticles containing p-benzoquinone or hydroquinone with better hydrophilicity were obtained with further reaction of pillararenes in the frameworks.Upon coordination with metal ions including Pd（II）by the porphyrin entities in the frameworks of CMPs,a heterogeneous catalytic system,Pd@DMP[5]-TPP-CMP,could be facilely constructed in organic solvents under ambient conditions,owing to the robustness of DMP[5]-TPP-CMP and the formation of metalloporphyrins.Benefiting from the intrinsic cavities of the macrocycles and the extrinsic porous structures of the networks,these CMP microparticles hold great potentials in cargo storage and separation,and organic catalysis.