Tröger’s base (TB) and its derivatives have been studied extensively due to their unique concave shape stemming from the endomethylene strap. However, the strap-clipped TB chemistry has been largely overlooked in metal–organic framework (MOF) solids, leading to a gap in our knowledge within this field. In this work, we report the in situ strap elimination of a carboxylate-carrying TB in the presence of formic acid, both in solution and in Zr(IV)-based MOFs. In the solution system, the methanodiazocine nucleus can be exclusively transformed into an N,N′-diformyl-decorated phenhomazine derivative, regardless of the solvent used (DMF, DMA, or DEF), as unambiguously uncovered by single crystal X-ray crystallography. In contrast, while in the MOF synthetic system, the degree of derivatization reaction can be effectively controlled to give either the secondary diamine or formyl-decorated diamine, depending on the solvent used (DMF or DEF), resulting in the formation of two Zr-MOFs with 8-connected bcu (NU-1900) and 12-connected fcu (NU-407) topologies, respectively. The derivatization mechanism is proposed to be topology-guided and dependent on the local acid concentration during the MOF formation processes. Moreover, we discovered a novel post-synthetically water-induced in situ linker formylation process in NU-1900 through sequential formic acid elimination, migration, and condensation processes, affording an isostructural framework with the same linker as in NU-407, which further corroborates our proposed mechanism. Additionally, the highly defective NU-1900 with abundant accessible Zr sites was demonstrated to be an outstanding catalyst for the detoxification of a nerve agent simulant with a half-life of less than 1 min.

中文翻译：

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Tröger 在溶液中和基于 Zr(IV) 的金属有机骨架中的基础化学

Tröger 碱 (TB) 及其衍生物由于其源自内亚甲基带的独特凹形而得到广泛研究。然而，金属有机骨架 (MOF) 固体中的带夹 TB 化学在很大程度上被忽视了，导致我们在该领域的知识存在差距。在这项工作中，我们报告了在甲酸存在的情况下，在溶液和基于 Zr(IV) 的 MOF 中原位带消除携带羧酸盐的 TB。在溶液体系中，methanodiazocine nucleus 可以完全转化为N , N'-二甲酰修饰的苯并嗪衍生物，无论使用何种溶剂（DMF、DMA 或 DEF），单晶 X 射线晶体学明确揭示了这一点。相反，在 MOF 合成系统中，可以有效控制衍生化反应的程度，根据使用的溶剂（DMF 或 DEF）生成仲二胺或甲酰基修饰的二胺，从而形成两个 Zr-具有 8 个连接的bcu (NU-1900) 和 12 个连接的fcu的 MOF(NU-407) 拓扑结构，分别。衍生化机制被认为是拓扑引导的，并且取决于 MOF 形成过程中的局部酸浓度。此外，我们通过连续的甲酸消除、迁移和缩合过程在 NU-1900 中发现了一种新的合成后水诱导的原位接头甲酰化过程，提供了与 NU-407 中具有相同接头的同构框架，这进一步证实了我们提议的机制。此外，具有大量可及 Zr 位点的高度缺陷 NU-1900 被证明是半衰期小于 1 分钟的神经毒剂模拟物解毒的杰出催化剂。