Single-Site Cobalt Catalysts at New Zr_(12)(μ_3-O)_8(μ_3-OH)_8(μ2-OH)_6 Metal-Organic Framework Nodes for Highly Active Hydrogenation of Nitroarenes, Nitriles, and Isocyanides

摘要

We report here the synthesis of a robust and porous metal-organic framework (MOF), Zr_(12)-TPDC, constructed from triphenyldicarboxylic acid (H_2TPDC) and an unprecedented Zr_(12) secondary building unit (SBU): Zr_(12)(μ_3-O)_8(μ_3-OH)_8(μ_2-OH)_6. The Zr_(12)-SBU can be viewed as an inorganic node dimerized from two commonly observed Zr_6 clusters via six μ_2-OH groups. The metalation of Zr_(12)-TPDC SBUs with CoCl_2 followed by treatment with NaBEt_3H afforded a highly active and reusable solid Zr_(12)-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.