The transformation of two-dimensional (2D) covalent–organic frameworks (COFs) into three-dimensions (3D) is synthetically challenging, and it is typically addressed through interlayer cross-linking of alkene or alkyne bonds. Here, we report the first example of the chemical reconstruction of a 2D COF to a 3D COF with a complete lattice rearrangement facilitated by base-triggered boron hybridization. This chemical reconstruction involves the conversion of trigonal boronate ester linkages to tetrahedral anionic spiroborate linkages. This transformation reticulates the coplanar, closely stacked square cobalt(II) phthalocyanine (PcCo) units into a 3D perpendicular arrangement. As a result, the pore size of COFs expands from 2.45 nm for the initial 2D square lattice (sql) to 3.02 nm in the 3D noninterpenetrated network (nbo). Mechanistic studies reveal a base-catalyzed boronate ester protodeboronation pathway for the formation of the spiroborate structure.

中文翻译：

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硼连接共价有机框架的 2D 到 3D 重建


将二维 (2D) 共价有机框架 (COF) 转化为三维 (3D) 在综合上具有挑战性，通常通过烯烃或炔键的层间交联来解决。在这里，我们报告了第一个将 2D COF 化学重建为 3D COF 的例子，并通过碱基触发的硼杂化促进了完整的晶格重排。这种化学重构涉及将三方硼酸酯键转变为四面体阴离子螺硼酸酯键。这种转变将共面、紧密堆叠的方形钴 (II) 酞菁 (PcCo) 单元网状排列成 3D 垂直排列。结果，COF 的孔径从初始 2D 方晶格 (sql) 的 2.45 nm 扩展到 3D 非互穿网络 (nbo) 中的 3.02 nm。机理研究揭示了形成螺硼酸酯结构的碱催化硼酸酯原脱硼途径。