Design And Synthesis Of Novel Bridged Pillar[5]arene Oligomers And Construction Of Their Supramolecular Polymers

Pillar[5]arene was discovered by Ogoshi in 2008 as a new generation of macrocyclic host molecule.Owing to its unique rigid,symmetrical pillar architecture,and easy modification properties,pillar[5]arene has attracted significant attention and has been widely used in many fields,such as drug delivery,organic solar cells,OLED,etc.Recently the construction of bridged pillar[5]arene oligomers starts receiving more attention to fabricate various functional supramolecular polymeric materials.However,some issues are still challenging for supramolecular scientists,such as developing dynamic bridged pillar[5]arene oligomers by non-covalent bond,and the introduction of photo-responsive or chiral properties into pillar[5]arene based supramolecular system,which might bring some new fascinating features,like new optical properties,and environmental responsiveness.Thus in this thesis,different strategies are applied to generate a series of pillar[5]arene oligomers such as dimers,trimers,tetramers and then their construction of functional supramolecular polymers were studied via different self-assembling mechanisms.The contents and results are as following:(1)To incorporate photo-responsive fluorescent properties into pillar[5]arene based supramolecular polymer system,a new cyanostilbene bridged pillar[5]arene dimer was synthesized through Knoevenagel condensation of pillar[5]arene-substituted phenylacetonitrile with pillar[5]arene-substituted benzaldehyde.Then,the supramolecular polymerization was confirmed by introducing neutral guest G1 through host-guest interaction,and its photo-responsive properties were further characterized by UV-Vis spectroscopy,fluorescence spectroscopy,~1H NMR,DOSY NMR,SEM,and viscosity measurements.(2)To introduce chiral and morphological transition properties into pillar[5]arene based supramolecular polymer system,a new pillar[5]arene trimer was designed and synthesized with the aid of benzene-1,3,5-tricarboxamide(BTAs)as the bridge.Furthermore,the introduction of different guests G1 and G2,the hyperbranched supramolecular polymers and different morphology transition were successfully obtained by different self-assembly mechanisms.The morphology transitions and hyperbranched supramolecular polymers formation were further characterized by H NMR,CD,DOSY NMR,SEM,and viscosity measurements.(3)Finally,in order to introduce more dynamic properties into pillar[5]arene based supramolecular polymer system,a novel bridged pillar[5]arene tetramer based on non-covalent interaction was designed and synthesized by two different pillar[5]arene dimers decorated with naphthalene diimide bridged pillar[5]arene(NDI-P),and naphthalene bridged pillar[5]arene(NAP-P),respectively.These different pillar[5]arene can be assembled via X-type charge transfer interactions.Furthermore,the introduction of a di-topic neutral guest into the new pillar[5]arene tetramer gave cross-linked supramolecular polymeric gel through host-guest interactions.The cross-linked polymers were confirmed by concentration-dependent 1H NMR spectroscopy,DOSY NMR,UV-vis,SEM,and viscosity measurements.