Single-Site Cobalt Catalysts at New Zr₁₂(μ₃‑O)₈(μ₃‑OH)₈(μ₂‑OH)₆ Metal–Organic Framework Nodes for Highly Active Hydrogenation of Nitroarenes, Nitriles, and Isocyanides

We report here the synthesis of a robust and porous metal–organic framework (MOF), Zr12-TPDC, constructed from triphenyl­dicarboxylic acid (H2TPDC) and an unprecedented Zr12 secondary building unit (SBU): Zr12(μ3-O)8­(μ3-OH)8­(μ2-OH)6. The Zr12-SBU can be viewed as an inorganic node dimerized from two commonly observed Zr6 clusters via six μ2-OH groups. The metalation of Zr12-TPDC SBUs with CoCl2 followed by treatment with NaBEt3H afforded a highly active and reusable solid Zr12-TPDC-Co catalyst for the hydrogenation of nitroarenes, nitriles, and isocyanides to corresponding amines with excellent activity and selectivity. This work highlights the opportunity in designing novel MOF-supported single-site solid catalysts by tuning the electronic and steric properties of the SBUs.