Tailoring the structure, pH sensitivity and catalytic performance in Suzuki–Miyaura cross-couplings of Ln/Pd MOFs based on the 1,1′-di(p-carboxybenzyl)-2,2′-diimidazole linker

Abstract

An array of heterobimetallic Pd/Ln MOFs (1-4) with Sm, Eu, Tb, Dy as preferred metal nodes and 1,1'-di(p-carboxybenzyl)-2,2'-diimidazole (H2L) as a fairly suitable bifunctional organic linker have been synthesized, fully characterized and tested as catalysts in cross-coupling reactions. These robust MOFs, ensuring a uniform distribution of Pd, showed excellent stability in air and high catalytic activity in Suzuki-Miyaura reactions conducted in neat water, neat ethanol as well as water-ethanol mixture. Depending on the solvent, complex 1 could be effectively recycled 4-8 times without significant loss of catalytic activity. Importantly, this complex was found to be pH responsive in a reversible way, enabling convenient recovery from acidic aqueous solutions, indicating good recyclability as well as environment-friendly separation of the metal residues after the reaction.

Engineering Metal–Organic Framework Catalysts for C−C and C−X Coupling Reactions: Advances in Reticular Approaches from 2014–2018

“…As eries of heterobimetallic lanthanide MOFs was synthesized by Youa nd co-workers [196] forS uzuki-Miyaura coupling. Figure 57.…”

“…A series of heterobimetallic lanthanide MOFs was synthesized by You and co‐workers for Suzuki–Miyaura coupling. The MOFs were synthesized from the nitrate salts of Sm, Eu, Tb, and Dy, 1,1′‐di( p ‐carboxybenzyl)‐2,2′‐diimidazole, and K 2 PdCl 4 .…”

Efficient Suzuki–Miyaura C-C Cross-Couplings Induced by Novel Heterodinuclear Pd-bpydc-Ln Scaffolds

“…The heteronuclear bimetallic palladium compounds 1 – 3 have been synthesized in a one-pot procedure, according to the previously published methodology [88,89,90]. A mixture of K 2 PdCl 4 (0.29 mmol), 2,2′-bipyridine-5,5′-dicarboxylic acid (0.29 mmol), Ln(NO 3 ) 3 ·6H 2 O (0.18 mmol) and water (10 mL) was stirred for 20 min in open air.…”

“…In both chemical transformations, the new class of complexes displayed an excellent catalytic activity (yields of 99% in Heck reaction and 98% in Suzuki–Miyaura reaction) as compared to state of the art. Applying an alternative metallolig and strategy for MOF construction [86,87], a new set of heterobimetallic Pd/Ln MOFs with Sm, Eu, Tb, Dy, as lanthanide nodes, interconnected by a distinct bifunctional organic linker, 1,1′-di( p -carboxybenzyl)-2,2′-diimidazole, has been prepared [88]. This novel class of MOFs showed excellent stability in air and water and displayed high catalytic activity in Suzuki–Miyaura reactions conducted both homogeneously and heterogeneously, in neat water, ethanol or water–ethanol.…”

Microflowers formed by complexation-driven self-assembly between palladium(ii) and bis-theophyllines: immortal catalyst for C–C cross-coupling reactions

“…[21][22][23] Robust MOF with a uniform distribution of Pd shows excellent stability in air and high catalytic activity in Suzuki-Miyaura reaction, and thus Pd-MOF showed good performance in recyclability with easy-handing separation. [24][25][26] N-heterocyclic carbene (NHC) complexes like imidazolium-based complexes have strong sigma donor capability and electron-richness which is similar to tertiary phosphine ligands activating the oxidative addition step in the catalytic cycle of cross-coupling reactions. [27][28][29][30] As extension of NHC catalytic system, magnetic and silica-supported NHC heterogeneous catalysts were also reported.…”