Reticular Synthesis of High-Connectivity Metal-Organic Frameworks with Kuratowski-Type Building Blocks

Metal-organic frameworks (MOFs) with Kuratowski-type Zn₅ building blocks represent a class of materials with interesting properties. However, most single-crystalline Zn₅-benzotriazolate-based MOFs are based on ditopic ligands, significantly limiting the spatial arrangement of these nodes within frameworks and therefore restricting functionalities. Herein, we applied state-of-the-art reticular chemistry to the rational assembly of hexatopic benzotriazolate ligands and Kuratowski-type Zn₅ nodes into a high-connectivity single-crystalline MOF, Zn-Tz₆Mes. Zn-Tz₆Mes exhibits the rare node-morphing nia-derived tsb net. Subsequent postsynthetic modification of Zn-Tz₆Mes introduced open Cu(I) sites, yielding Cu^I-Zn-Tz₆Mes. Cu^I-Zn-Tz₆Mes displays markedly enhanced binding affinities toward π-acidic gases such as H₂ and N₂, in comparison to the parent Zn-Tz₆Mes. This work allows the reticular arrangement of Kuratowski-type building blocks within framework crystals with controllable structures and fine-tuned functionalities, paving the way for unlocking the unlimited potential of Kuratowski-type clusters in designed porous materials.