Tang Xihao, Zhang Kai, Xue Ruxiao, Zheng Yuexin, Chen Simin, Zheng Shengrun, Fan Jun, Zhang Yuwei, Ye Weiping, Zhang Weiguang, Cai Songliang, Liu Yi
GDMPA Key Laboratory for Process Control and Quality Evaluation of Chiral Pharmaceuticals, Guangzhou Key Laboratory of Analytical Chemistry for Biomedicine, School of Chemistry, South China Normal University, 510006, Guangzhou, P. R. China.
SCNU Qingyuan Institute of Science and Technology Innovation Co., Ltd., 511517, Qingyuan, P. R. China.
Angew Chem Int Ed Engl. 2024 Dec 9;63(50):e202413171. doi: 10.1002/anie.202413171. Epub 2024 Oct 24.
Exploring self-standing chiral covalent organic framework (COF) thin films with controllable circularly polarized luminescence (CPL) is of paramount significance but remains a challenging task. Herein, we demonstrate the first example of self-standing chiral COF films employing a polymerization-dispersion-filtration strategy. Pristine, low-quality chiral COF films were produced by interfacial polymerization and then re-dispersed into COF colloidal solutions. Via vacuum assisted assembly, these COF colloids were densely stacked and assembled into self-standing, pure chiral COF films (L-/D-CCOF-F) that were transparent, smooth, crack-free and highly crystalline. These films were tunable in thicknesses, areas, and roughness, along with strong diffuse reflectance circular dichroism (DRCD) and cyan CPL signals, showing an intrinsic luminescence asymmetric factor (g) of ~4.3×10. Furthermore, these COF films served as host adsorbents to load various achiral organic dye guests through adsorption. The effective chiral transfer and energy transfer between CCOF-F and achiral fluorescent dyes endowed the dyes with strong chirality and tunable DRCD, resulting in intense, full-color-tunable solid-state CPL. Notably, the ordered arrangement of dye guest molecules within the preferentially oriented chiral pores of CCOF-F contributed to an amplified |g| factor of up to 7.2×10, which is state-of-the-art for COF-based CPL materials. This work provides new insights into the design and fabrication of self-standing chiral COF films, demonstrating their great potential for chiroptical applications.
探索具有可控圆偏振发光（CPL）的自支撑手性共价有机框架（COF）薄膜具有至关重要的意义，但仍然是一项具有挑战性的任务。在此，我们展示了采用聚合-分散-过滤策略制备自支撑手性COF薄膜的首个实例。通过界面聚合制备出原始的、质量较差的手性COF薄膜，然后将其重新分散到COF胶体溶液中。通过真空辅助组装，这些COF胶体被密集堆叠并组装成自支撑的、纯手性COF薄膜（L-/D-CCOF-F），该薄膜透明、光滑、无裂纹且具有高度结晶性。这些薄膜在厚度、面积和粗糙度方面具有可调性，同时具有强烈的漫反射圆二色性（DRCD）和青色CPL信号，其固有发光不对称因子（g）约为4.3×10⁻³。此外，这些COF薄膜作为主体吸附剂，通过吸附作用负载各种非手性有机染料客体。CCOF-F与非手性荧光染料之间有效的手性转移和能量转移赋予了染料强大的手性和可调的DRCD，从而产生强烈的、全色可调的固态CPL。值得注意的是，染料客体分子在CCOF-F优先取向的手性孔内的有序排列导致|g|因子放大至高达7.2×10⁻³，这是基于COF的CPL材料中的最高水平。这项工作为自支撑手性COF薄膜的设计和制备提供了新的见解，展示了它们在旋光应用中的巨大潜力。
