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 (t)Bu(L-PdTFA) is an ineffective catalyst owing to decomposition under the catalytic conditions, highlighting the beneficial effects of immobilization.

A Zr metal–organic framework (MOF) 1-CoCl3 has been synthesized by solvothermal reaction of ZrCl4 with a carboxylic acid-functionalized CoIII-PNNNP pincer complex H4(L-CoCl3) ([L-CoCl3]4– = [(2,6-(NHPAr2)2C6H3)­CoCl3]4–, Ar = p-C6H4CO2 –). The structure of 1-CoCl3 has been determined by X-ray powder diffraction and exhibits a csq topology that differs from previously reported ftw-net Zr MOFs assembled from related PdII- and PtII-PNNNP pincer complexes. The Co-PNNNP pincer species readily demetallate upon reduction of CoIII to CoII, allowing for transmetalation with late second and third row transition metals in both the homogeneous complex and 1-CoCl3 . Reaction of 1-CoCl3 with [Rh­(nbd)­Cl]2 (nbd = 2,5-nobornadiene) results in complete Rh/Co metal exchange at the supported diphosphine pincer complexes to generate 1-RhCl, which has been inaccessible by direct solvothermal synthesis. Treating 1-CoCl3 with PtCl2(SMe2)2 in the presence of the mild reductant NEt3 resulted in nearly complete Co substitution by Pt. In addition, a mixed metal pincer MOF, 1-PtRh, was generated by sequential substitution of Co with Pt followed by Rh.

NOBF4 enables efficient oxidative ligand exchange in a Pd pincer MOF, generating a highly active and recyclable Lewis acid catalyst.