Postsynthetic Metal Exchange in a Metal–Organic Framework Assembled from Co(III) Diphosphine Pincer Complexes

Abstract

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.

Controlled Synthesis of Large Single Crystals of Metal‐Organic Framework CPO‐27‐Ni Prepared by a Modulation Approach: In situ Single‐Crystal X‐ray Diffraction Studies

“…The almost infinite combination of various linkers and metal clusters unlocks a range of functionalities in these frameworks. Porosity paired with functionality opens a wide field of potential applications for MOFs, including battery materials, [3–5] catalysis, [6–9] gas separation [10–14] and storage, [15–19] as well as biomedical applications [20–24] . The majority of these applications rely on guest‐host interactions.…”

Zn(II)-to-Cu(II) Transmetalation in an Amide Functionalized Complex and Catalytic Applications in Styrene Oxidation and Nitroaldol Coupling

“…Several metal-organic frameworks (MOFs) have been employed in transmetalation to synthesize novel materials which would otherwise be difficult to obtain [12][13][14][15]. The role of ligands in the process cannot be ruled out.…”

Catalytic Activity of a Zr MOF Containing POCOP-Pd Pincer Complexes

“…Diphosphine pincer ligands are widely used in homogeneous catalysis owing to their stability and versatility. − Recently, we and others have been interested in immobilizing diphosphine pincer complexes in MOFs and other porous materials to investigate the effects of site isolation and heterogenization on catalytic activity, stability, and recyclability. − For example, Byers and Tsung have shown that encapsulation of PNP-Ru complexes in UiO-66 improves their activity toward CO 2 hydrogenation and offers protection from thiol poisoning . P O C O P-Ir complexes have also been immobilized at the Zr 6 metal nodes of NU-1000 using a solvent-assisted ligand-incorporation approach, and the resulting material was found to catalyze gas-phase hydrogenation of ethylene to ethane .…”

“…P O C O P-Ir complexes have also been immobilized at the Zr 6 metal nodes of NU-1000 using a solvent-assisted ligand-incorporation approach, and the resulting material was found to catalyze gas-phase hydrogenation of ethylene to ethane . We have recently reported the synthesis and characterization of Zr MOFs assembled from linkers based on Co, Ru, Pd, and Pt diphosphine pincer complexes. − Several of these pincer MOFs have shown improved catalytic activity or selectivity compared to homogeneous counterparts, and the differences in reactivity could be attributed to site isolation and secondary environment effects provided by the rigid MOF scaffold.…”