Synthesis And Properties Of Novel Hybrid Urea/silicon Macrocycles

Macrocycles usually have unique geometries,pre-organized recognition cavities,and tunable guest-binding abilities,allowing for a wide range of applications in molecular recognition,self-assembly,catalysis,and transmembrane transport.However,the development of macrocyclic compounds with diverse structures and functions has become one of the important topics in the field of supramolecular chemistry.This thesis describes the efficient synthesis and properties of novel functional macrocyclic compounds.The maintext includes three parts:In the first part,the development of supramolecular chemistry is firstly overviewed,followed by the brief introduction of anion recognition in supramolecular chemistry,the structural characteristics of anions and the principles of anion recognition,as well as the anion receptors.Next,recent advances in urea-containing macrocyclic anion receptors is discussed in greater details.Finally,the research progress of silicon-based macrocycles in recent decades is also summarized.In the second part,through literature research and rational design,we started to synthesize a diarylamine intermediate（II-3）.Then,a series of urea-containing macrocyclic compounds（II-4a～II-4c）with C₂ symmetry were obtained by triphosgene in one-pot synthesis.The structures of these macrocyclic compounds were fully characterized by ¹H NMR,¹³C NMR and HRMS（ESI）.Besides,the structure of II-4c was further charaterized by single crystal X-ray diffraction analysis.Further NMR spectroscopic analysis and UV spectroscopy titration experiments indicated that II-4a～II-4c show weak or no binding to Cl^–,Br^–,I^–,NO₃^–,SCN^–,HSO₄^–and SO₄^2–.In contrast,all three macrocyclic receptors showed strong binding of H₂PO₄^–ions（log KII-4a=3.86;log KII-4b=5.01;log KII-4c=5.98）.This allows us to conclude that II-4a～II-4c also have elegant selectivity toward H₂PO₄^–ion.In addition,macrocycle II-4c was also examplifed to bind two H₂PO₄^–but not one or two HSO₄–alone.However,II-4c was found capable of selectively binding hybrid binary oxoanions（i.e.,one H₂PO₄^–and one HSO₄^–）to form a heterodianionic complex（H₂PO₄^–·HSO₄^–）?II-4c.To the best of our knowledge,this is the first report for a synthetic macrocyclic anion receptor to selectively and simultaneously bind hybrid dianions,that’s H₂PO₄^–·HSO₄^–.In the third part,we have developed an efficient synthesis method for a class of silicon-based macrocycles.Firstly,three novel silicon-based macrocycles（II-5～II-7）featuring good crystallinity were synthesised in 40%-50%yields using aromatic diphenols（hydroquinone,bisphenol A）and dichlorosilanes（diphenyldichlorosilane,dichlorodimethylsilane）in a"one-pot"reaction.The advantages of these reactions are the availability of inexpensive raw materials,the short reaction route,the simplicity of the experiments,the good crystallinity of the products and the ability to achieve gram-scale preparation（no need for high dilution concentration）.All the macrocycles were characterized by ¹H NMR,¹³C NMR and single crystal X-ray diffraction analysis.In addition,further NMR spectroscopy and powder X-ray diffraction（PXRD）analysis indicated that macrocycles II-5 and II-7 could be used for the adsorption of dichloromethane and benzene vapour,respectively,based on the unique structure of the macrocycle per se.