Research On The Design, Synthesis And Application Of Chiral AIE Molecules Based On Binaphthol

Chiral fluorescent materials have important application value in the frontier fields of optoelectronic devices,asymmetric catalysis,information storage,biocoding,etc.,and have received extensive attention from researchers in recent years.The chiral naphthol(BINOL)is one of the most commonly used chiral optical frameworks,but the chiral molecule based on the BINOL backbone exhibit an abnormal aggregation-annihilation CD(AACD)phenomenon.,which limits the application of CD in the aggregate state.In this paper,different lengths of bridging alkyl chains were embedded in 3,3-dicyanomethylidene functionalized BINOL,and a series of chiral aggregation-induced luminescence(AIE)fluorescent molecules were obtained(BINB-n,n?1?8).As the length of the bridging alkyl chain changes,the twist angles of the two naphthalene rings of the BINOL skeleton gradually change,thereby realizing the transition of the CD signal from AACD to retention(APCD)during aggregation.In order to study whether the introduction of different sterically hindered protecting groups can also regulate CD signals during aggregation,this paper introduces different sterically hindered protecting groups(methyl,tert-butyldimethylsilane,tert-butyldiphenylsilane).In the 3,3-dicyanomethylene functionalized BINOL,the results show that the CD signal is significantly weakened during the aggregation process,that is,the presence of AACD,indicating that BINOL without embedded bridging alkyl chain has certain flexibility.Can not effectively inhibit the CD quenching effect.Since the compound BINB-6 has a significant AIE effect,different donors(4-(trifluoromethyl)phenyl,phenyl,4-methoxyphenyl,5-methyl-2-thiophenyl,4-(Diphenylamino)phenyl)was introduced into BINB-6 to construct a series of chiral AIE molecules with adjustable spectra(BINB-6A?BINB-6E).The solid-state emission wavelength covers 522?623 nm.Importantly,due to the strong signal of BINB-6,the influence of the introduced electron-donating group on the CD signal is negligible,that the CD signal is maintained in the aggregate state.Since BINB-6 derivatives have a typical AIE effect,we have studied their solid-state circularly polarized light(CPL).Self-assemblies of BINB-6 derivatives were prepared by slowly evaporating the solvent.Except for the compound BINB-6E,the self-assemblies of other chiral AIE molecules have significant CPL spectra.The asymmetric factor(glum)of the compound BINB-6D can reach 1×10-2.It is expected to be used in the fields of fluorescence sensing,biomarkers,and information storage.