Sequence Engineering in Tuning the Circularly Polarized Luminescence of Aggregation-Induced EmissionActive Hetero[3]rotaxanes

Based on a [2]rotaxane precursor with exchangeable pentafluorophenyl ester stoppers, a new wheelassembling approach has been successfully developed for the precise sequence control of hetero[3] rotaxanes, leading to the facile and efficient synthesis of both sequence isomers of hetero[3]rotaxanes. More importantly, taking advantage of the chirality retention along with the wheel-assembling process, corresponding sequence isomers of chiral AIEgenfunctionalized hetero[3]rotaxanes were further precisely synthesized. Impressively, the resultant hetero[3]rotaxanes revealed remarkable sequencedependent aggregation-induced emission (AIE) behavior and circularly polarized luminescence performance with large dissymmetry factors up to 0.012, highlighting the great power of the newly coined sequence engineering concept in developing novel AIE -active chiroptical materials. This proof-ofconcept study lays the foundation for investigation of the structure-property relationships of heterorotaxanes that can further direct the rational design and precise synthesis of sequence-defined heterorotaxanes with desirable properties for practical applications.