Design,Synthesis And Properties Of Fluorene Polycatenar,Azo-Ferrocene And Diphenyl Sulfone Dendrimer Molecules

Liquid crystal is one of the excellent representative in the self-assembly systems.It is the mesophase state between liquid and crystal,which has both the fluidity of liquid and the periodicity of crystal.It has anisotropic physical properties and is easy to respond to external stimuli such as forces,magnetic fields and electric fields,so it is widely used in displays,sensors,and life sciences.Introducing heterocyclic aromatic hydrocarbons into the liquid crystalline molecular skeleton through various C-C coupling reactions can give liquid crystalline molecules a complex liquid crystal phase and excellent photoelectric properties,thereby obtaining functional materials with excellent performance.The first chapter is about the design,synthesis and properties of D-A-D type polycatenar molecules based on 9-fluorenone and 9-dicyanomethylenefluorene.Firstly,the definition and research status of polycatenar molecules are introduced.Secondly,the research status of compounds containing 9-fluorenone and thiophene are introduced.Thirdly,we introduce the research status of 9-dicyanomethylenefluorene derivatives Finally,the research progress on self-assembly of fluorenone and9-dicyanomethylenefluorene derivatives is summarized.Related background research shows that the research of 9-fluorenone and 9-dicyanomethylenefluorene derivatives is mainly focused on organic optoelectronic materials,and there are few reports on liquid crystalline self-assembly and gel self-assembly.But usually the self-assembled structure of the materials can determine their properties,therefore,we have designed D-A-D type polycatenar molecules FOTE³/m and FMTE³/m,which containing 9-fluorenone or9-dicyanomethylenefluorene as electron-accepting unit and thiophene as electron-donating unit.The liquid crystalline assembly property,photoelectric property,ion recognition property and gel assembly property of these compounds were studied.With the change of the alkyl chain,all compounds self-assembled into a columnar phase except FMTE³/10*and FOTE³/17*.Small angle X-ray scattering studies have demonstrated that the compounds FOTE³/16 and FMTE³/16 can self-assemble into a Col_hex/p6mm phase.After the carbonyl group in FOTE³/m converting to dicyanovinyl,the FMTE³/m compounds’UV-visible absorption peaks have a significant red shift,and the energy gap of the thin film is reduced,which makes it as a potential organic semiconductor material.In addition,the compound FMTE³/16 can selectively detect CN^-in THF solution,and the compound FMTE³/10*can self-assembled into a 3D network gel with helical structure in ethyl acetate.This multifunctional material has broad application prospects in liquid crystalline displays,organic optoelectronic materials,ion sensors and gel materials.The second chapter is about the design,synthesis and properties of molecules containing azobenzene and ferrocene.Firstly,the structure and application fields of azobenzene and ferrocene groups are introduced.Secondly,the research status of low molecular compounds containing azobenzene and ferrocene are introduced.Finally,we introduce the research status of polymers containing azobenzene and ferrocene.Related background research shows that azobenzene group has good photoresponse and ferrocene group has good electroresponse.Combining the two groups into the same molecule functional materials with multiple stimulus responses could be obtained.In this chapter,we designed and synthesized the azo-ferrocene compounds Azo-Fc-m by Click reaction and studied the thermotropic property,photoelectric property and gel assembly property of these compounds.Our studies have shown that due to the poor coplanarity of the molecule and the large steric hindrance of the ferrocene group,theπ-πstacking effect between the molecules is inhibited,and the compounds have no liquid crystalline property.The compound Azo-Fc-14 has good photoresponse in solution,and the energy gap of thin film is 3.58 e V.The Compound Azo-Fc-14 can also self-assembled into a 3D network gel in a solution of ethyl acetate:ethanol=5:1.This versatile material has broad application prospects in optical switches,organic optoelectronic materials and gel materials.The third chapter is about the design,synthesis and properties of diphenyl sulfone dendrimer.First,we introduce the research status of dendrimers,and then introduce the research status of diphenyl sulfone derivatives.In this chapter,we designed and synthesized the second-generation diphenyl sulfone amide compound IIA⁴/10 by Click reaction and studied the thermogenic assembly property,gel assembly property and ion recognition property of this compound.We also compared these properties with the first-generation diphenyl sulfone amide compounds and the second-generation diphenyl sulfone ether compound synthesized by our research group.Studies have shown that the compound IIA⁴/10 has no liquid crystalline property,but it has higher melting point and crystallizing point than the first-generation amide compounds and the second-generation ether compound.Notably for amide compounds,the gels of the compounds which have less dendrons usually showed more ordered structures.In addition,the compound IIA⁴/10 can selectively detect Cu²⁺in a mixed solution of CH₃CN:CH₂Cl₂=2:1,indicating that it has potential for application as a highly sensitive fluorescent chemical sensor.The fourth chapter is the summary and outlook of this thesis.The fifth chapter is about the detailed synthesis steps and spectrum data.