Synthesis And Properties Of A Novel Luminescent Liquid Crystal Based On Cyanostilbene

Compared with non-light-emitting liquid crystals,light-emitting liquid crystals show great advantages in simplifying device design,low energy consumption,high brightness and contrast.The discovery of AIE（Aggregation-induced Emission）has greatly promoted the development of the organic field,and is now also widely used in the field of fluorescent imaging of living cells,fluorescent probes,and the like.However,conventional fluorophores and highly ordered molecules in crystals can cause fluorescence quenching.These shortcomings limit their applications in the fields of optoelectronics,biomedicine,and other fields.Introducing the AIE concept into liquid crystals can overcome the shortcomings of liquid crystal compounds themselves,so as to obtain a special liquid crystal material that emits light efficiently under high concentration or solid film.AIE LCD’s provides a valuable strategy for developing liquid crystal devices with simplified structures and low energy consumption.Whether it is a discotic liquid crystal that can form a special columnar stack through self-assembly,or a bowl-shaped liquid crystal with a rigid planar structure,or an ionic liquid crystal that has a large difference from the characteristics of conventional liquid crystals due to its ionic characteristics,The field of light-emitting devices shows broad application prospects.Therefore,in this article we combine the latest research trends,Derivatives with AIE properties were synthesized with cyanodistilbene molecules as the core,and liquid crystal materials with special properties were synthesized with the skeletons of cyclotrisveratene,calix[4]arene,porphyrin,and 1-methylimidazole.details as follows:1.Designed and synthesized different numbers of flexible tricyclic resveratrol and calix[4]arene bowl liquid crystals.The photophysical properties and liquid crystal properties of the target compound indicate that different flexible chains will affect their fluorescence and liquid crystal properties.The more alkyl chains,the larger the liquid crystal range.2.AIE ionic liquid crystal derivatives with 1 and 2 flexible chains were explored and synthesized.And replace its complex anions.It was found that changing the anion would affect the aggregate fluorescence intensity of the compound(Fl_{（iodide ion）}>Fl_{（p-toluenesulfonate ion）}>Fl_{（trifluoroacetate ion）}).The liquid crystal temperature range will change with the change of anions and show Tl（trifluoroacetate ion）>Tl（p-toluenesulfonate ion）>Tl（iodine ion）.Compounds with two long alkyl chains have an overall mesogenic temperature range greater than compounds with only one long alkyl chain.3.Prepared AIE ionic liquid crystal derivatives with chiral flexible chain lengths.The investigation found that the longer the alkyl chain,the larger the mesogenic temperature range.The capacitance current increases with the increase of the scanning rate,showing a good stability of the electrolyte.And proved that it has circular polarization fluorescence performance,forming a left-handed structure.4.Designed and synthesized of porphyrin derivatives with chiral AIE units.It is proved that there is a strong AIE-FRET effect between stilbene molecules and porphyrin units.The target compound showed a hexagonal columnar liquid crystal morphology,which proved to have good liquid crystal performance.CPL proved that it has circularly polarized fluorescence performance,a g_lum value of-1.36×10^-3,and formed a left-handed structure.