The Fabrication Of Several Novel Supramolecular Host Compounds-based Crystalline Materials For Applications

The creation and development of various macrocyclic receptors with specifically tailored structures and excellent host-guest properties are always one of the cutting-edge research topics along with the rapid development of host-guest and supramolecular chemistry,and also played a vital role in prompting the rapid advancement in supramolecular functional materials.In retrospect,five generations of prevalent macrocyclic compounds,i.e.,crown ethers,cyclodextrins,calixarenes,cucurbiturils,and pillararenes,are the most representative examples.Function-directed derivatizations endow them great contribution to different research fields,including but not limited to molecular recognition,nanomaterials,molecular machinery,drug delivery,highly sensitive sensors,extraction and separation,complicated architectures construction,stimuli responsive materials and biomimetics.This dissertation is mainly focused on the design and synthesis of several novel macrocyclic/acyclic supramolecular receptors,and their applications in construction of crystalline materials for molecular adsorption and separation,which can be summed up as the following six parts:In the first part,a new version of macrocyclic arenes,namely leaning pillar[6]arenes(LP6),has been designed and synthesized for the first time.It can be treated as a tilted version of a pillar[6]arene with two unsubstituted phenylene subunits.In comparison with traditional pillar[6]arene,more flexible skeleton,lower in-cavity ? electron density,and stronger polarization effect along the rims strongly affected the cavity adaptability and binding properties of LP6.Furthermore,this study also provides a more simple and intuitive explanation for the ability of pillar[6]arene to maintain its pillar-like and rigid structure.In addition,a series of LP6 derivatives were successfully designed and synthesized,resulting in a water-soluble macrocyclic host based on a leaning pillar[6]arene(CWLP6).The presence of eight positive charges made the molecule an effective anionic naphthalenesulfonate receptor.Above all,based on the novel structure,multiple functionalized modification sites,and excellent host-guest properties,we are confident that leaning pillar[6]arenes will find a wide range of applications in supramolecular energy materials,biomimetics,crystal engineering,and other related research fields.In the second part,we describe the first fabrication of NACs based on perethylated leaning pillar[6]arene(referred to as Et LP6-NAC).Et LP6-NAC could selectively uptake 1-bromoalkane isomers over their 2-positional isomers by simple solid-vapor adsorption.Single-crystal structure analysis in conjunction with thermoanalysis suggest that the selectivity is derived from the different host–guest binding modes and the relative stabilities between the Et LP6 crystalloids loaded with1-and 2-bromoalkane isomers.Significantly,the 1-bromoalkane–adsorbed assemblies are highly stable at room temperature and Et LP6-NAC can be reused many times without any decrease in performance.In the third part,we first describe the successful use of Et LP6-NAC in the highly efficient separation of n-hexane(n Hex)and methylcyclopentane(Mcp).Et LP6-NAC could selectively separate n Hex from an equimolar mixture of n Hex-Mcp with a purity of about 97%,by the methods of both lossless solid-vapor phase adsorption and high speed solid-liquid phase adsorption.Meanwhile,we have further proved that the high selectivity in capturing n Hex is still remained in relatively complicated C6 alkanes/cyclanes mixed systems,suggesting the great potential of Et LT6-NAC in practical industrial hexane production.In the fourth part,a new version of acyclic receptor,namely molecular clip(MC),has been successfully designed and synthesized via a facile one-pot Friedel-Crafts alkylation reaction.Single crystal diffraction data provide an intuitive and straightforward explanation,not only for its well-preorganized conformation but also for its tunable and selective guest-binding capability.Moreover,we have demonstrated that MC could construct a variable-speed cyclic adsorption system for iodine solution uptake,where facile switching among the high-,middle-,and low-speed adsorption rate was achieved as a result of the crystalline phase manual control.Importantly,our results led to a new concept of molecular crystal gearshift,where such an organic small molecule can be employed as an adsorbent in pollutant disposal with a specified range of operating rates.In the fifth part,we presented a new kind of macrocyclic arene,namely geminiarene(GA),which was vividly designated according to its hybrid para-and meta-positional connection mode,two different but interconvertible molecular configurations and symmetries in the crystalline state.Besides,different conformations of GA exhibited opposite binding capability and selectivity toward the same guest species,and different guests also can accurately induce GA to form different conformations and host-guest assemblies.Finally,adsorptive separation of chlorobenzene and chlorocyclohexane mixture with intriguing single or dual selectivity could be achieved by constructing and using crystalline materials of GA.In the sixth part,we presented a skeleton-enlarged version of geminiarene,namely elongated-geminiarene(El GA for short),by the replacement of xylylene units with biphenylene units in geminiarene.El GA shows great features including easy and scalable synthesis,nanometer-sized cavity,rich blend of conformational features,and excellent solid-state host–guest properties.Moreover,we found that the functional crystalline materials of El GA have great application potentials in the separation of aromatics and cyclic aliphatics mixtures.