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