[5]Helicene Based π‐Conjugated Macrocycles with Persistent Figure‐Eight and Möbius Shapes: Efficient Synthesis, Chiral Resolution and Bright Circularly Polarized Luminescence
Qifeng Zhou, Yuan Wei, Yunfei Li, Yi Han, Lintao Bao, Wei Fan, Liuying Jiao, Yanli Zhao, Yong Ni, Ya Zou, Hai‐Bo Yang, Jishan Wu
Abstract
Abstract π‐Conjugated chiral shape‐persistent molecular nanocarbons hold great potential as chiroptical materials, though their synthesis remains a considerable challenge. Here, we present a simple approach using Suzuki coupling of a [5]helicene building block with various aromatic units, enabling the one‐pot synthesis of a series of chiral macrocycles with persistent figure‐eight and Möbius shapes. Single‐crystal structures of 7 compounds were solved, and 22 enantiomers were separated by preparative chiral HPLC. A notable pyrene‐bridged figure‐eight macrocycle, with its rigid, fully π‐conjugated and overcrowded structure, exhibited pure excimer emission and outstanding circularly polarized luminescence (CPL) properties, including a large dissymmetric factor (| g lum |=3.8×10 −2 ) and significant CPL brightness ( B CPL =710.5 M −1 cm −1 ). This method provides a versatile synthetic platform for producing various chiral D 2 ‐symmetric figure‐eight macrocycles and singly or triply twisted Möbius macrocycles with C 2 and D 3 symmetry, offering tunable chiroptical properties for CPL applications.