Improved Catalytic Activity and Stability of a Palladium Pincer Complex by Incorporation into a Metal–Organic Framework

A porous metal–organic framework Zr₆O₄(OH)₄(L-PdX)₃ (<b>1-X</b>) has been constructed from Pd diphosphinite pincer complexes ([L-PdX]^4– = [(2,6-(OPAr₂)₂C₆H₃)­PdX]^4–, Ar = <i>p</i>-C₆H₄CO₂^–, X = Cl, I). Reaction of <b>1-X</b> with PhI­(O₂CCF₃)₂ facilitates I^–/CF₃CO₂^– ligand exchange to generate <b>1-TFA</b> and I₂ as a soluble byproduct. <b>1-TFA</b> is an active and recyclable catalyst for transfer hydrogenation of benzaldehydes using formic acid as a hydrogen source. In contrast, the homogeneous analogue ^{<b><i>t</i></b>}<b>Bu­(L-PdTFA)</b> is an ineffective catalyst owing to decomposition under the catalytic conditions, highlighting the beneficial effects of immobilization