In spite of their great promise for enantioselective processes due to the rich host-guest chemistry, it remains a challenge to construct covalent organic frameworks (COFs) with chiral three-dimensional (3D) structures. Here we report bottom-up synthesis of the first example of 3D chiral COFs by imine condensation of an enantiopure 2-fold symmetric TADDOL-derived tetraaldehyde with a tetrahedral tetra(4-anilyl)methane. After postsynthetic oxidation of imine linkages, the framework is transformed into an amide-linked COF with retention of crystallinity and permanent porosity as well as enhanced chemical stability. The resultant isostructural COFs feature a 4-fold interpenetrated diamondoid open framework with tubular channels decorated with chiral dihydroxy auxiliaries. Both COFs can be used as chiral stationary phases for high performance liquid chromatography to enantioseparate racemic alcohols, and the oxidized COF shows superior separation performance compared to the pristine framework.

中文翻译：

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用于高性能液相色谱对映分离的手性 3D 共价有机骨架

尽管由于丰富的主客体化学性质，它们在对映选择性过程中前景广阔，但构建具有手性三维 (3D) 结构的共价有机框架 (COF) 仍然是一个挑战。在这里，我们报告了第一个 3D 手性 COF 实例的自下而上合成，通过对映体纯 2 倍对称 TADDOL 衍生四醛与四面体四（4-苯胺基）甲烷的亚胺缩合。在亚胺键的合成后氧化后，框架被转化为酰胺连接的 COF，保留了结晶度和永久孔隙率，并增强了化学稳定性。由此产生的等结构 COF 具有 4 倍互穿菱形开放框架，管状通道装饰有手性二羟基助剂。