Kitano Tomoki, Goto Syunto, Wang Xiaohan, Kamihara Takayuki, Sei Yoshihisa, Kondo Yukihito, Sannomiya Takumi, Uekusa Hidehiro, Murakami Yoichi
Laboratory for Zero-Carbon Energy, Institute of Integrated Research, Institute of Science Tokyo, Tokyo, Japan.
Department of Mechanical Engineering, Institute of Science Tokyo, Tokyo, Japan.
Nat Commun. 2025 Jan 2;16(1):280. doi: 10.1038/s41467-024-55729-2.
Covalently bonded crystalline substances with micropores have broad applications. Covalent organic frameworks (COFs) are representative of such substances. They have so far been classified into two-dimensional (2D) and three-dimensional (3D) COFs. 2D-COFs have planar shapes useful for broad purposes, but obtaining good crystals of 2D-COFs with sizes larger than 10 μm is significantly challenging, whereas yielding 3D-COFs with high crystallinity and larger sizes is easier. Here, we show COFs with 2.5-dimensional (2.5D) skeletons, which are microscopically constructed with 3D bonds but have macroscopically 2D planar shapes. The 2.5D-COFs shown herein achieve large single-crystal sizes above 0.1 mm and ultrahigh-density primary amines regularly allocated on and pointing perpendicular to the covalently-bonded network plane. Owing to the latter nature, the COFs are promising as CO adsorbents that can simultaneously achieve high CO/N selectivity and low heat of adsorption, which are usually in a mutually exclusive relationship. 2.5D-COFs are expected to broaden the frontier and application of covalently bonded microporous crystalline systems.
具有微孔的共价键合晶体物质具有广泛的应用。共价有机框架（COF）是这类物质的代表。到目前为止，它们已被分为二维（2D）和三维（3D）COF。二维COF具有适用于广泛用途的平面形状，但要获得尺寸大于10μm的二维COF的良好晶体具有很大挑战性，而制备具有高结晶度和更大尺寸的三维COF则更容易。在这里，我们展示了具有2.5维（2.5D）骨架的COF，其在微观上由三维键构成，但在宏观上具有二维平面形状。本文展示的2.5D-COF实现了尺寸大于0.1毫米的大单晶尺寸，并且超高密度的伯胺规则地分布在共价键合网络平面上并垂直于该平面指向。由于后一种特性，这些COF有望成为能够同时实现高CO/N选择性和低吸附热的CO吸附剂，而这两个特性通常是相互排斥的。2.5D-COF有望拓宽共价键合微孔晶体系统的前沿领域和应用范围。
