Covalent Organic Frameworks with Tunable Chirality for Chiral-Induced Spin Selectivity

作者：Xing Han, Chao Jiang, Bang Hou, Yan Liu, Yong Cui · 发表于：Journal of the American Chemical Society · 年份：2024 · DOI：10.1021/jacs.3c13032 · 被引用次数：63 · 研究领域：Covalent Organic Framework Applications、Metal-Organic Frameworks: Synthesis and Applications、Perovskite Materials and Applications

Chiral covalent organic frameworks (CCOFs) have attracted extensive interest for their potential applications in various enantioselective processes. However, the exploitation of chirality-induced spin selectivity (CISS) that enables a new technology for the injection of spin polarized current without the need for a permanent magnetic layer within CCOFs remains a largely untapped area of research. Here, we demonstrate that, for the first time, COFs can be an attractive platform to develop spin filter materials with efficient CISS. This facilitates the design and synthesis of a new family of Zn(salen)-based 2D CCOFs, namely, CCOFs-9–12, by imine condensation of chiral 1,2-diaminocyclohexane and tri- or tetra(salicylaldehyde) derivatives. CCOF-9, distinguished by its unique C 2 symmetric “armchair” tetrasubstituted pyrene conformation, exhibits the most pronounced chirality among these materials and serves as a solid-state host, enabling the enantioselective adsorption of racemic drugs with an enantiomeric excess (ee) of up to 97%. After substituting diamagnetic zinc(II) ions for paramagnetic cobalt(II), the resulting CCOF-9-Co not only retains its high crystallinity, porosity, and exceptional chirality but also exhibits enhanced conductivity, a crucial factor for the effective observation of CISS. Magnetic conductive atomic force microscopy showed that CCOF-9-Co exhibited a remarkable CISS effect with up to an 88–94% spin polarization ratio. This phenomenon is further confirmed...