Uniform Spherical Chiral Polyrotaxane with Steerable Circularly Polarized Luminescence

Abstract

Spherical chiral polyrotaxane (CPR) with steerable circularly polarized luminescence (CPL) are intriguing as advanced chiroptical materials but have not been reported to date. Here, we constructed spherical chiral polyrotaxane (CPR) materials with steerable CPL by utilizing cyclodextrins (α-, β-, or γ-CyD) as the chiral wheel. Importantly, the structure and the CPL performance of the CPR materials can be regulated by varying the feeding amount and the type of cyclodextrins (α-, β-, or γ-CyD). It was found that the spherical reticular frame and chiral polyrotaxane structure were indispensable for CPL generation of spherical CPR due to the strengthen of confined chirality transfer by structural and spectral characterization. Remarkably, spherical β-CyD/CPR at Feed(C/B)=4, 8, 16 showed higher quantum yield and longer photoluminescence lifetime in comparison with those of α-CyD/CPR and γ-CyD/CPR. This work demonstrates the example of a CPL-active spherical CPR and provides insight into macrocyclic size-dependent CPL generation through mechanically interlocked strategy and covalent reticular chemistry, which will be helpful for the future design of high-performance CPL materials.