Synthesis And Properties Of Aryl-Substituted Pyrrole Derivatives With Chiral Functional Group

Considering that the number of chiral pendants should influence the photophysical properties,the optical activity and the self-assembling behaviours of the AEE-active molecules,two pairs of enantiomers and their raceme by introducing three or two chiral/achiral 1-phenylethylamine attachments to the central conjugated pentaphenylpyrrole moiety were designed and synthesized,their structures were characterized and verified by¹H NMR,IR,MS and Elemental Analysis.The pair of enantiomers（S）-P5P-3AM,（R）-P5P-3AM,which with three chiral1-phenylethylaime substituents,and their raceme rac-P5P-3AM exhibit obvious AEE features,while the enantiomers（S）-P5P-2AM,（R）-P5P-2AM,which with two chiral1-phenylethylaime substituents,and their raceme rac-P5P-2AM exhibit very weak AEE properties.The chirality of the chial attachments have little effects on the AEE behaviours when comparing the photoluminescence properties of the enantiomers with their racemes.Both the two pairs of enantiomers,（S）-/（R）-P5P-3AM and（S）-/（R）-P5P-2AM exhibit distinct aggregation-induced circular dichroism（AICD）with mirror-image Cotton effects upon aggregation.And the chiral compounds（S）-P5P-3AM,（R）-P5P-3AM exhibit chiral-polarized luminescence（CPL）properties with emission dissymmetry factor(g_em)in0.5×10^-35×10^-3 for（S）-P5P-3AM and-1×10^-3-6×10^-3 for（R）-P5P-3AM in DMSO-water mixture with water fraction of 40%.The chiral compounds（S）-/（R）-P5P-3AM tended to form larger orderly aligned nanofibers,which tightly heaped together and formed nanofibers aggregations,and the（S）-/（R）-P5P-2AM could self-assemble into helical nanofibers,but their raceme rac-P5P-3AM and rac-P5P-2AM only form nanoparticles blocks,suggesting the chiral induction effect on the molecular self-assembling.