Boosting Circularly Polarized Luminescence from Alkyl-Locked Axial Chirality Scaffold by Restriction of Molecular Motions

Abstract

Boosting the circularly polarized luminescence of small organic molecules has been a stubborn challenge because of weak structure rigidity and dynamic molecular motions. To investigate and eliminate these factors, here, we carried out the struc-ture-property relationship studies on a newly-developed axial chiral scaffold of bidibenzo[b,d]furan. The molecular rigidity was finely tuned by gradually reducing the alkyl-chain length. The environmental factors were considered in solution, crystal, and polymer matrix at different temperatures. As a result, a significant amplification of the dissymmetry factor glum from 10-4 to 10-1 with a 146-fold magnification was achieved, corresponding to the situation from (R)-4C in solution to (R)-1C in polymer film at room temperature. A synergistic strategy of increasing the intramolecular rigidity and enhancing the inter-molecular interaction to restrict the molecular motions was thus proposed to improve circularly polarized luminescence. The though-out demonstrated relationship will be of great importance for the development of high-performance small organic chiroptical systems in the future.

Initialing Circularly Polarized Room-Temperature Phosphorescence from Purely Organic Luminophore Aggregate

“…Therefore, our group systematically studied its influence on the dissymmetry factor of circularly polarized emission through molecular design and environmental regulation in an axial chiral system (Scheme 3c). 23 The results showed that molecular motions could be effectively suppressed by increasing the molecular rigidity and the intermolecular interactions. Furthermore, a photothermally activated PVA film was applied to achieve CR-RTP with stimuli-responsive amplification in the dissymmetry factor.…”