Facile synthesis of NHC-stabilized Ni nanoparticles and their catalytic application in the Z-selective hydrogenation of alkynes

Abstract

Well defined Ni nanoparticles (NiNPs) stabilized with N-heterocyclic carbenes (NHCs) have been synthesized through a new methodology involving the decarboxylation of a zwitterionic CO adduct. Their catalytic performance was tested in the partial hydrogenation of alkynes into (Z)-alkenes under very mild reaction conditions (50 °C and 5 bar H pressure), providing excellent activities and selectivities.

Direct Synthesis of N‐Heterocyclic Carbene‐Stabilized Copper Nanoparticles from an N‐Heterocyclic Carbene–Borane

“…[3,4] Although metallicn anoparticles (NPs) have ap romising range of applications,d epending on the physical and chemical properties of the metal, examples of NHC-stabilized nanoparticles are still limited to few metals (Scheme 1, left). [4,5] Common strategies fort heir preparation rely on the reductiono fa no rganometallic precursor (isolated or generated in situ) [6][7][8][9][10][11] or ligand exchange. [11][12][13] In spite of numerousw orks concerningt heir syntheses anda pplications, [14] Cu NPs are still challenging to prepare as ac olloidal solution that is resistant to aggregation over time and with a metals urfacet hat is neither oxidized nor hydroxylated as long as it is kept under inert atmosphere.…”

Nickel Nanoparticles Stabilized by Trisimidazolium Salts: Synthesis, Characterization and Application as Recyclable Catalysts for the Reduction of Nitroarenes

“…Moreover, dispersions of Ni NPs in different types of ionic‐liquids have been obtained by auto‐decomposition, or microwave‐induced decomposition of Ni(COD) 2 (COD=1,5‐cyclooctadiene). This zero‐valent organometallic complex has also been used as starting compound for the production of Ni NPs following the Chaudret's organometallic approach,, consisting in the reduction and subsequent displacement of a ligand from a metal(0) organometallic precursor.…”

“…Most of these reported nickel nanocatalysts are stabilized/immobilized on a variety of polymers, matrices or supports (doped graphenes, or reduced graphene oxide, polyethylene, chitosan, SiO 2 , Fe 3 O 4 ‐SiO 2 ‐P4VP, layered double hydroxide(LDH)/layered double oxide (LDO), polyamidoamine‐polyvinylamine/SBA‐15, polyacrylamides, Fe 3 O 4 , carboxymethyl cellulose, poly(vinylpyrrolidone), NiFe 2 O 4 /carbon nanofiber), or are naked Ni NPs, generated in situ from a nickel(II) source and Li‐arene. The incorporation of N ‐heterocyclic carbenes (NHC) into the matrix or the use of these ligands for the stabilization of Ni NPs in solution have been described. Also imidazolium‐based ionic liquids,,, and poly(ionic liquids) have been employed to prepare dispersions of Ni NPs.…”

Organometallic Nanoparticles Ligated by NHCs: Synthesis, Surface Chemistry and Ligand Effects

“…In fact, following this new methodology, a great number of new NHC-stabilized organometallic NPs have been prepared, including various metals such as, Ru, Pt, Ni and Ir, and numerous non-isolable NHCs with different structures and morphologies, such as chiral [20], longchain [13,23] or hydrosoluble [48] NHCs (Figure 4). A third methodology based in the decarboxylation of a zwitterionic CO2 adduct has been recently reported by Claver et al [49]. Here, 1,3-dialkylimidazolium-2-carboxylate, of general formula R2Im-CO2, was used as a carbene precursor for the formation of NHC-stabilized organometallic NPs.…”