Unveiling reactive metal sites in a Pd pincer MOF: insights into Lewis acid and pore selective catalysis

Abstract

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

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

“…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.…”

“…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 .…”

“…This material showed a dramatic increase in catalytic activity for transfer hydrogenation of aldehydes compared to both the parent MOF, 1-PdX , and the homogeneous analogue, t Bu 4 P O C O P-PdTFA. NOBF 4 was found to facilitate I – /BF 4 – oxidative ligand exchange at P N N N P-PdI linkers in 2-PdI to cleanly generate 2-PdBF 4 . The latter showed superior catalytic activity for the intramolecular cyclization of o -alkynyl anilines compared to the TFA-exchanged analogue 2-PdTFA .…”

Engineering Nanoscale Metal‐Organic Frameworks for Heterogeneous Catalysis

“…The pores with specific category show distinct absorption capacity for small molecules and then affect the catalytic performance of active centers. [ 127–130 ] Carefully designed cages allow for facilitating the production of fine chemicals with purposefully high selectivity. Loading active species into the channels not only enhances their stability but also provides additional chances to regulate the catalytic performance.…”

Restricting Polyoxometalate Movement Within Metal-Organic Frameworks to Assess the Role of Residual Water in Catalytic Thioether Oxidation Using These Dynamic Composites

“…The active sites in catalysts are often sensitive to their surrounding environments. Consequently, active site engineering has been developed to allow the modulation of a catalyst environment to exploit or inhibit activity (Pikus et al, 1997;Garce et al, 2009;Nasalevich et al, 2014;Liu et al, 2018;Reiner et al, 2019); however, tuning of the solid support, as in single-site heterogeneous catalyst systems, is often difficult to achieve. For this reason, metal-organic frameworks (MOFs) with a high degree of tunability are attractive support materials (Vermoortele et al, 2012;Vandichel et al, 2015;Liu et al, 2018;Palmer et al, 2018).…”