The Fixed Propeller-Like Conformation of Tetraphenylethylene that Reveals Aggregation-Induced Emission Effect, Chiral Recognition, and Enhanced Chiroptical Property

The propeller-like conformation of
tetraphenylethylene (TPE) with
aggregation-induced emission (AIE) effect was partially and completely
fixed by intramolecular cyclization for the first time. The immobilization
of propeller-like conformation was found to show great advantages
in determining the enantiomer purity, identifying the chiral amines.
The completely fixed conformers are resolved into M- and P-enantiomer, which showed mirror imaged CD
and almost quantitative fluorescence quantum yield. Furthermore, it
also showed a mirror and large circularly polarized luminescence dissymmetric
factor, depending on the helicity of the enantiomer. The result provides
the most direct and persuasive evidence for AIE via the restriction
of intramolecular rotation and finds the new insight of the compounds
in chiroptical property.