Robust Corrole-Based Metal–Organic Frameworks with Rare 9-Connected Zr/Hf-Oxo Clusters

Abstract

The corrole unit from the porphyrinoid family represents one of the most important ligands in the field of coordination chemistry, which creates a unique environment allowing for the observation of unusual electronic states of bound metal cations and has shown great promise in various applications. Nevertheless, studies that directly and systematically introduce these motifs in porous crystalline materials for targeting further functionalizations are still lacking. Herein, we report for the first time the construction of two robust corrole-based metal-organic frameworks (MOFs), M₆(μ₃-O)₄(μ₃-OH)₄(OH)₃(H₂O)₃(H₃TCPC)₃ (M = Zr for <b>Corrole-MOF-1</b> and M = Hf for <b>Corrole-MOF-2</b>, H₃TCPC = 5,10,15-tris(<i>p</i>-carboxylphenyl)corrole), which are assembled by a custom-designed <i>C</i>_2<i>ν</i>-symmetric corrolic tricarboxylate ligand and the unprecedented <i>D</i>_3<i>d</i>-symmetric 9-connected Zr₆/Hf₆ clusters. The resultant frameworks feature a rare (3,9)-connected <b>gfy</b> net and exhibit high chemical stability in aqueous solutions within a wide range of pH values. Furthermore, we successfully prepared the cationic <b>Corrole-MOF-1(Fe)</b> from the iron corrole ligand, which can serve as an efficient heterogeneous catalyst for [4 + 2] hetero-Diels-Alder reactions between unactivated aldehydes and a simple diene, outperforming both the homogeneous counterpart and the porphyrinic MOF counterpart.