Synergistically Boosting the Circularly Polarized Luminescence of Functionalized Pillar[5]arenes by Polymerization and Aggregation

Abstract

Supramolecular polymers based on chiral macrocycles have attracted increasing attention in the field of circularly polarized luminescence (CPL) owing to their unique properties. However, the construction of macrocyclic supramolecular polymers with highly efficient CPL properties in aggregate states still remains challenging. Herein, w e constructed a class of macrocycle-based coordination polymers by combining the planar chiral properties of pillar[5]arene with the excellent fluorescence properties of aggregation-induced emission luminogens. The formation of polymers enhances both the fluorescence and chiral properties, resulting in chiral supramolecular polymers with remarkable CPL properties. Increasing the aggregation degree of the polymers can further improve their CPL properties, as evidenced by a 21-fold increase in the dissymmetry factor and an over 25-fold increase in the fluorescence quantum yield in the aggregate state compared to the solution state. Such a synergistic effect of polymerization- and aggregation-enhanced CPL can be explained by the restriction of intramolecular motions and aggregation-induced conformation confinement. This work provides a promising method for developing highly efficient CPL supramolecular polymers.