N-Heterocyclic Carbene (NHC)-Stabilized Ru0 Nanoparticles: In Situ Generation of an Efficient Transfer Hydrogenation Catalyst

Kathuria, L and Din Reshi, NU and Samuelson, AG (2020) N-Heterocyclic Carbene (NHC)-Stabilized Ru0 Nanoparticles: In Situ Generation of an Efficient Transfer Hydrogenation Catalyst. In: Chemistry - A European Journal, 26 (34). pp. 7622-7630.

PDF Che_Eur_Jou_26_34_ 7622-7630_2020.pdf - Published Version Restricted to Registered users only Download (1MB) | Request a copy

Abstract

Tethered and untethered ruthenium half-sandwich complexes were synthesized and characterized spectroscopically. X-ray crystallographic analysis of three untethered and two tethered Ru N-heterocyclic carbene (NHC) complexes were also carried out. These RuNHC complexes catalyze transfer hydrogenation of aromatic ketones in 2-propanol under reflux, optimally in the presence of (25 mol %) KOH. Under these conditions, the formation of 2–3 nm-sized Ru0 nanoparticles was detected by TEM measurements. A solid-state NMR investigation of the nanoparticles suggested that the NHC ligands were bound to the surface of the Ru nanoparticles (NPs). This base-promoted route to NHC-stabilized ruthenium nanoparticles directly from arene-tethered ruthenium–NHC complexes and from untethered ruthenium–NHC complexes is more convenient than previously known routes to NHC-stabilized Ru nanocatalysts. Similar catalytically active RuNPs were also generated from the reaction of a mixture of [RuCl2(p-cymene)]2 and the NHC precursor with KOH in isopropanol under reflux. The transfer hydrogenation catalyzed by these NHC-stabilized RuNPs possess a high turnover number. The catalytic efficiency was significantly reduced if nanoparticles were exposed to air or allowed to aggregate and precipitate by cooling the reaction mixtures during the reaction.

Item Type:	Journal Article
Publication:	Chemistry - A European Journal
Publisher:	Wiley-VCH Verlag
Additional Information:	The copyright for this article belongs to Wiley-VCH Verlag.
Keywords:	Chlorine compounds; Hydrogenation; Ketones; Mixtures; Nanocatalysts; Nanoparticles; Nuclear magnetic resonance spectroscopy; Potassium hydroxide; Ruthenium compounds; X ray crystallography, Aromatic ketones; Catalytic efficiencies; Half-sandwich complexes; N-heterocyclic carbenes; Ru nanoparticles; Ruthenium Nanoparticles; Transfer hydrogenations; X-ray crystallographic analysis, Synthesis (chemical)
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	06 Feb 2023 07:12
Last Modified:	06 Feb 2023 07:12
URI:	https://eprints.iisc.ac.in/id/eprint/79868

Actions (login required)

View Item