Stable Polyoxometalate-Based Metal-Organic Framework: Synthesis, Modification, and Catalytic Activity

Metal-organic frameworks (MOFs) with polyoxometalates (POMs) as the nodes usually feature a high stability. Those with available space and modifiable groups are expected to serve as a catalytic platform. In this work, a polyoxometalate-based metal-organic framework (POMOF)-bearing channel with a transversal surface of ca. 1.1 × 1.8 nm, [Ni(en)₂]₄H{[Ni₆(tris)(en)₃(SIP)_1.5][B-α-PW₉O₃₄]}₂·32H₂O (1), was resulted by the collaboration of multiple ligands. The channel was lined with abundant amino groups that bonded with water molecules in it via hydrogen bonds. Compound 1 exhibited excellent thermal and chemical stabilities, which was confirmed by immersion experiments, in situ variable temperature powder X-ray diffraction, and reversible dehydration-hydration behavior. Pristine 1 showed remarkable activity in the hydrogen evolution reaction. According to the presence of amino groups in the channel, 1 was modified by Pd species. Resultantly, Pd was loaded into the channel successfully. The yielding material 1-Pd smoothly catalyzed the Suzuki-Miyaura coupling reactions.