Synthesis And Characterization Of Aggregation-induced Emission Liquid Crystal Material-C₃ Symmetry Dendritic Molecules Derivative

In this thesis,we successfully synthesized two series of liquid crystal compounds with“aggregation-induced emission”?AIE?effects,which are derivatives with triphenyl triazine as the core and triphenyl benzene as the core,respectively.Their molecular structures,luminescent properties and liquid crystal phase structure were characterized by nuclear magnetic resonance?NMR?,fluorescence spectrum?PL?,UV-vis spectrum,polarizing optical microscope?POM?,differential scanning calorimetry?DSC?and thermogravimetric analysis?TGA?and X-ray diffraction?1D/2D-WAXD?.The main contents of this thesis are as follows:In the first chapter,the discovery,development history,research status and application prospect of liquid crystal are summarized.Traditional liquid crystal do not emit fluorescence,and belong to passively display.The concept of AIE was applied to the design of liquid molecules,in order to obtain the luminescent liquid crystal.Therefore,the concept,molecular structure and luminescent mechanism of AIE were introduced.The characteristics and research progress of liquid crystal molecules with C₃ symmetry structure are introduced.Finally,the molecular design concept of AIE-liquid crystal is summarized.In the second chapter,the reagents instruments and various characterization methods used in this thesis were summarized.In the third chapter,a series of AIE-liquid crystal based on triphenyl triazine derivative were designed and synthesis.They are QHC6,QHC12,DHC6 and DHC12,respectively.UV-vis absorption and fluorescence spectra show that QHC6 and QHC12 have the properties of aggregation-induced emission?AIE?,but DHC6 and DHC12 do not.The liquid crystalline phase behavior was analyzed by DSC and POM,the results show that they all have liquid crystalline properties and exhibit different liquid crystalline phase structures.Therefor,the QHC6 and QHC12 after grinding can show blue emitting and almost no emitting at the synthesized state.The crystal structure and liquid crystalline structure of QHC6 and QHC12 dendritic molecules derivative were studied by one-dimensional and two-dimensional X-ray diffraction.The preliminary results of DHC6 and DHC12 indicate that both yellow and green light are emitted in crystalline and liquid crystalline state.In the fourth chapter,a series of AIE-liquid crystal based on triphenyl benzene derivative were designed and synthesis.They are BHC6,BHC12.UV-vis absorption and fluorescence spectra show that BHC6 and BHC12 have the properties of aggregation-induced emission?AIE?.The liquid crystalline phase behavior was analyzed by DSC and POM,the results show that they all have liquid crystalline properties and exhibit different liquid crystalline phase structures.BHC6 and BHC12 exhibit typical force chromism behavior,synthesized BHC6and BHC12 emit green fluorescence while they emit blue fluorescence after grinding.