Macrocycle-based Functional Materials And Their Applications In Adsorption And Separation

Macrocyclic receptors are not only an important tool of supramolecular chemistry but also a great motive force for the development of supramolecular chemistry.In the past,several generations of classical macrocycles such as crown ether,cyclodextrin,calixarene and cucurbituril,have been discovered one after another,and have been investigated in variety of areas,including host-guest chemistry,self-assembly,biomedicine,and material science.Pillar[n]arenes,as a new type of macrocyclic host reported for the first time in 2008,have become a hot topic in recent years due to their symmetrically rigid structure and good host-guest properties.In 2015,our group developed a new macrocycle namely biphen[n]arene and investigated their host-guest behaviors.In this dissertation,we mainly focused on the applications of functional solid materials based on pillar[n]arenes and extended biphen[n]arenes in adsorption and separation,which mainly includes the following parts:In the first part,we studied the capture of chemical weapon of sulfur mustard(SM)by activated per-ethylated pillar[5]arene(Et P5)crystal materials.First,we systematically investigated the host-guest complexation behaviors between Et P5 with SM and its simulants not only in solution but also in the solid state.The results indicated that the association constant between SM and Et P5 was determined to be(6.2±0.6)×10³ M^-1 in o-xylene-d₁₀.Single crystal structure of SM@Et P5 showed that SM was fully engulfed by Et P5 cavity to form a 1:1 inclusion complex,which was driven by multiple C–H···?/Cl/S hydrogen bonds and S···?interactions.In addition,activated crystal materials of Et P5(Et P5?)could effectively adsorb SM simulants at solid-vapor phase;powder X-ray diffraction patterns and host-guest crystal structures indicated that the uptake of guest molecules triggered a solid-state structural transformation.More interestingly,the captured guest molecules could be stably contained in Et P5?for at least 6 months in air at room temperature.In the second part,we studied the separation of industrially important cis/trans-1,2-dichloroethylene(cis/trans-DCE)isomers by activated Et P5 crystals.Et P5 can selectively bind trans-DCE over cis-DCE isomer forming inclusion complexes both in solution and in the solid state.The selectivity comes from the suitability of size/shape between Et P5 and trans-DCE.In addition,we utilized activated Et P5 crystals(Et P5?)to low-energy-consuming separate trans-DCE from a cis/trans-isomer equimolar mixture with a 94.94%selectivity.Powder and single crystal X-ray diffraction analyses reveal that the vapor adsorption induce crystalline structure transformation from Et P5?to trans-DCE@Et P5 crystals.In the third part,we reported that the marriage of macrocycle chemistry and co-crystal engineering provided a smart strategy to build vapochromic materials.The macrocycle co-crystals have been constructed by?-electron rich pillar[5]arene(P5)and an electron-deficient pyromellitic diimide derivative(PDI).P5-PDI are in red color due to the formation of charge-transfer(CT)complex.After removing solvent,a white crystalline solid with a new structure(P5-PDI?)is yielded,which exhibits selective vapochromic responses to volatile organic compounds(VOCs)of haloalkanes,accompanied by color changes from white to red or orange.Powder and single crystal X-ray diffraction analyses reveal that the color changes are attributed to the vapor-triggered solid-state structural transformation to form CT co-crystals.In the fourth part,we investigated the self-assemble into supramolecular gels,and iodine capture of terphen[n]arenes(TPns)(n=3-6)and quaterphen[n]arenes(QPns)(n=3-6).We found cyclic pentamers and hexamers could easily form supramolecular organogels(G-TP5,G-TP6,G-QP5,G-QP6)in dichloromethane/hexane solution.The gelation process presumably occurs due to self-assembly between macrocyclic molecules through?···?stacking interactions.More interestingly,the xerogels were found to act as novel adsorbent materials for iodine capture not only in aqueous solution(<10 ppm)but also in the vapor phase(0.67 g g^-1),and could be recycled multiple times without obvious performance loss.