Synthesis And Performance Study Of [6] Helicene Of An Organic Small-molecule Fluorescent Material

Organic luminescent materials have the advantages of clear structure and rich variety,and have potential application value in the fields of information storage and processing,chip devices,optical pseudodiscrimination protection and molecular optical switching.In recent decade,spironenes organic small molecule compounds due to the inherent helical chirality and good optical properties,rapid development in a variety of fields,however,due to the fluorescence performance of spironene compounds itself is generally poor,asymmetric luminescence factor is smaller,luminescence efficiency is low,and the synthesis method of spironene is limited,often need to use expensive chiral column or high performance liquid chromatography split,high cost,is limited in the practical application in the field of organic luminescent materials.Therefore,we envisage introducing different substituents and oxanthenene(PXX)structures in the molecular structure of spironenes,and further designing novel spironenoid organic fluorescent materials with high asymmetry factors and high fluorescence properties.Taking chiral naphthol as the starting material,the [6]helicene preolefin was synthesized through a series of simple and safe reactions,and then bromine hexacolenes were synthesized by photoring off reaction,resulting in a pair of high purity diastereoisomers with a ratio of about 1:2.The diastereoisomers could be isolated and purified by column chromatography.Then,three different substituted groups,styrene,methoxy and cyanyl,were introduced to enhance the fluorescence intensity of hexaspirenenes,and six pairs of [6]helicene compounds were obtained,all of which had good fluorescence properties.Then,the synthesized compounds were characterized and various optical properties were tested.The results show that the [6]helicene compounds produced all blue fluorescence in solution and light yellow fluorescence in solid state.Compared with the [6]helicene without any substituent,the fluorescence performance and fluorescence quantum yield were greatly improved with any substituent.At the same time,according to the literature can know the fluorescence performance of four compared to four ene is enhanced a lot,but four spirenene olefin compounds is almost no chirality,we synthesized six spirenene alkene compounds than rotation is very high,at the same time has a strong CPL signal and high asymmetric light factor,for the development of spirenoid circular polarization luminescent material provides a new way of thinking.In addition,according to the relevant literature synthesis of styrene replaced[6]helicene,get a pair of diastereoisomers,product ratio of about 1:1,also through column chromatography separation can purification,yield is high,and then under the action of catalyst oxidation buckle into a [6]helicene(PXX)structure.Through nuclear magnetic and mass spectrometry to confirm its structure,finally for ultraviolet absorption,fluorescence emission,optical optical performance test.The results show that the synthesis of PXX spirene compound and without spironenes,the fluorescence intensity is enhanced,and the wavelength of redshift,at the same time PXX structure compound synthesis method is very limited,combining PXX structure and spironene for the synthesis of spironene derivatives and research is a great innovation and breakthrough.