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

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 Corrole-MOF-1 and M = Hf for Corrole-MOF-2, H3TCPC = 5,10,15-tris­(p-carboxylphenyl)­corrole), which are assembled by a custom-designed C2ν-symmetric corrolic
tricarboxylate ligand and the unprecedented D3d-symmetric 9-connected Zr6/Hf6 clusters. The resultant frameworks feature a rare (3,9)-connected gfy net and exhibit high chemical stability in aqueous solutions
within a wide range of pH values. Furthermore, we successfully prepared
the cationic Corrole-MOF-1­(Fe) 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.