Yang Xue-Xian, Li Na, Li Chong, Jin Zhi-Bin, Ma Zhi-Zhou, Gu Zhi-Gang, Zhang Jian
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou Fujian 350002, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
J Am Chem Soc. 2024 Jun 12;146(23):16213-16221. doi: 10.1021/jacs.4c04125. Epub 2024 May 30.
Combining metal-organic frameworks (MOFs) with liquid crystals to construct liquid crystalline MOFs (LCMOF) offers the advantage of endowing and enhancing their functionality, yet it remains a challenging task. Herein, we report chiral liquid crystalline MOF (CLCMOF) thin films by cross-linking the chiral liquid crystals (CLC) with MOF thin films to realize highly circular polarization luminescence (CPL) performance with photo and thermal switching. By layer by layer cross-linking stilbene-containing CLC with stilbene-based MOF (CLC/MOF) thin film, the CLCMOF thin films were successfully obtained after UV irradiation due to the abundant [2 + 2] photocycloaddition. The resulted CLCMOF thin films have strong chirality, obvious photochromic fluorescent, and strong CPL performance (the asymmetry factor reaches to 0.4). Furthermore, due to the photochromic fluorescent MOF and thermotropic CLC, the CPL can be reversed and red-shifted after heating and UV irradiation treatment, showing photo- and thermal CPL switching. Such MOF-based CPL thin films with photo/thermal CPL switching were prepared to patterns and codes for the demonstration of potential application in advanced information anticounterfeit and encryption. This study not only opens a strategy for developing chiral thin films combining MOFs and liquid crystals but also offers a new route to achieve CPL switching in optical applications.
将金属有机框架（MOF）与液晶相结合以构建液晶MOF（LCMOF）具有赋予并增强其功能的优势，但这仍然是一项具有挑战性的任务。在此，我们报道了通过将手性液晶（CLC）与MOF薄膜交联来制备手性液晶MOF（CLCMOF）薄膜，以实现具有光和热开关功能的高度圆偏振发光（CPL）性能。通过将含芪的CLC与基于芪的MOF（CLC/MOF）薄膜逐层交联，由于丰富的[2 + 2]光环加成反应，在紫外线照射后成功获得了CLCMOF薄膜。所得的CLCMOF薄膜具有强手性、明显的光致变色荧光和强CPL性能（不对称因子达到0.4）。此外，由于光致变色荧光MOF和热致液晶CLC，在加热和紫外线照射处理后，CPL可以反转并红移，显示出光和热CPL开关特性。制备了具有光/热CPL开关的这种基于MOF的CPL薄膜图案和代码，以展示其在先进信息防伪和加密中的潜在应用。这项研究不仅为开发结合MOF和液晶的手性薄膜开辟了一种策略，而且为在光学应用中实现CPL开关提供了一条新途径。
