Synthesis And Characterization Of Trinuclear C-HBC Bis[7]helicene

Organic optoelectronic materials have great application potential in solar cells,flexible displays,carbon-based chips and other fields.The performance of organic optoelectronic materials is determined by the overall assembly of organic moieties,and the properties of these aggregated states are affected not only by the individual molecules themselves,but also by different molecular packing patterns.Therefore,controlling molecular packing is a key issue to obtain optimal optical and electronic properties,which is also a great challenge.Helicene is a star molecule in organic optoelectronic materials.It is a class of aromatic compounds formed by ortho-fused aromatic rings.Due to its inherent helical chirality,unique molecular structure and extended ?-conjugation properties,spiroenes have been widely used in recent years.Helicene molecules are roughly divided into three types.One is simple helicene,which is only composed of pure helicene units and is customarily named [n] helicene,that is,n benzene rings are fused at the ortho position;another is ? expansion,which is the extension of the ? plane on the basis of the helicene unit;the third is multiple helicene,which is generally formed by condensing multiple helicene units.The unique helical-twisted structure of helicene yields a series of excellent mechanical,electronic and optical properties,making helicenes useful in molecular springs,chiral optical materials,biomedicine and other fields.Hexabenzocoronene(c-HBC)is a six-fold [4] helicene,which has 13 benzene rings fused together.The center of c-HBC is a coronene plane fused by 7 benzene rings,and the other 6 benzene rings are alternately fused up and down with the coronene plane to form a twisted fused-ring aromatic hydrocarbon.Based on a single c-HBC molecule,this paper explores the design and synthesis of a C12-HBC-trimer molecule with a trinuclear c-HBC,bis[7]helicene structure and its ring-closed precursor molecule,which is predicted to have double helix complementary structure similar to that of DNA.The structural combination of trinuclear c-HBC and bis[7]helicene is expected to have excellent chiral optical properties,high asymmetry factor and high quantum yield,and it is expected to be used in 3D display,molecular machines and biomedicine in the future.