Synthesis And Properties Of Organic Fluorophores Based On Naphthalimide Group With Circularly Polarized Luminescence

Circularly polarized luminescence(CPL),as the emission analogue of circular dichroism(CD),which can be assigned as selective emission from left-or right-handed circularly polarized light of chiral fluorescence molecules,has become one of the most useful tools to investigate the excited state properties of chiral chromophores.Recently,the design and syntheses of novel CPL materials have attracted considerable attentions due to their potential application for bio-sensors,liquid crystal lasers,optical storage devices and 3D optical displays.More and more attention of CPL materials has been focused on chiral organic chromophores on view of their high emission quantum yields,easy processing and so on.Therefore,it is of great significance to develop excellent CPL materials of chiral organic chromophores with high glum value.In this dissertation,the studies focused on the design and synthesis of new CPL materials based on 1,8-naphthalimide,which was connected with different chirality sources such as chiral BINOL and chiral alanine.The main works of this dissertation are as follows:1.Two pairs of chiral 1,8-naphthalimide-based enantiomers incorporating D/L-alanine and pyrene fluorophore moieties have been designed and synthesized.The fluorescence emission gradually changes from bright-yellow to red when the fraction of the poor solvent methanol increases from 0 to 99 vol%.No obvious circular dichroism(CD)and circularly polarized luminescence(CPL)signals could be observed in the CHCl3 solution.Interestingly,D/L-1 can exhibit stronger red color CPL response signal than D/L-2 at fm=99%in the aggregate state due to the formation of regular and orderly self-assembly nano networks in the aggregate state via intermolecular ?-?interactions,and the optical anisotropy factor(glum)can reach as high as 0.013.In THF-H2O mixtuires,D/L-1 can show opposite CD and CPL singals compared with CHCl3-MeOH mixtures,of which the optical anisotropy factor(glum)can reach as high as 0.062.This phenomenon proved the effect of solvent effect on optical properties.2.Chiral BINOL-based 1,8-naphthalimide molecules exhibited aggregation-induced emission properties.They can show CD effects both in the THF and THF/H2O solution.Interestingly,they only show obvious circularly polarized luminescence signals in the THF/H2O mixed solution without reversal CPL signals,which could be attributed to the special intramolecular ?-? stack.R/S-BNDI can show CPL effects in both KBr pellet-dispersed solid state and spin-coating film state.the optical anisotropy factor(glum)of R/S-BNDI in the spin-coating film state can reach 0.034,higher than most common organic fluophores.