Atomically Precise Single Metal Oxide Cluster Catalyst with Oxygen‐Controlled Activity

Abstract

Single cluster catalysts (SCCs) consisting of atomically precise metal nanoclusters dispersed on supports represent a new frontier of heterogeneous catalysis. However, the ability to synthesize SCCs with high loading and to precisely introduce non‐metal atoms to further tune their catalytic activity and reaction scope of SCCs have been longstanding challenges. Here, a new interface confinement strategy is developed for the synthesis of a high density of atomically precise Ru oxide nanoclusters (Ru3O2) on reduced graphene oxide (rGO), attributed to the suppression of diffusion‐induced metal cluster aggregation. Ru3O2/rGO exhibits a significantly enhanced activity for oxidative dehydrogenation of 1,2,3,4‐tetrahydroquinoline (THQ) to quinoline with a high yield (≈86%) and selectivity (≈99%), superior to Ru and RuO2 nanoparticles, and homogeneous single/multiple‐site Ru catalysts. In addition, Ru3O2/rGO is also capable of efficiently catalyzing more complex oxidative reactions involving three reactants. The theoretical calculations reveal that the presence of two oxygen atoms in the Ru3O2 motif not only leads to a weak hydrogen bonding interaction between the THQ reactant and the active site, but also dramatically depletes the density of states near the Fermi level, which is attributed to the increased positive valence state of Ru and the enhanced oxidative activity of the Ru3O2 cluster for hydrogen abstraction.

Atom-Precise Low-Nuclearity Cluster Catalysis: Opportunities and Challenges

“…(a) Schematic illustration for the fabrication of Ru 3 O 2 /rGO catalysts by choosing Ru 3 (CO) 12 molecules as metal precursors. Reproduced with permission from ref , Copyright 2022 Wiley-VCH GmbH. (b) Utilize strong interactions and confinement of precursors for fabricating dual-atom iron catalysts on a carbon layer.…”

Engineering Single Atom Catalysts for Flow Production: From Catalyst Design to Reactor Understandings

“…9 A higher isolated yield (47%) was obtained via a Ru 3 O 2 /rGO-catalyzed Friedlander synthesis under the optimized condition. 10 Likewise, Chen et al developed a phosphorus-coordinated Rh 1 SAC for the hydroformylation of olefins using synthesis gas (H 2 and CO) with high conversion (>99%) and high regioselectivity toward the branched aldehyde (>90%, or a branched to linear ratio of 13.3). This allowed a step-and atom-economical synthesis of ibuprofen and fendiline in high yields.…”

“…The chemical orthogonality (a subset of independent chemoselectivity) of SACs enables the replication of molecular catalysis for the synthesis of complex molecules. , Traditionally, this proceeds through a single-site mechanism via sequential, domino, or multicomponent reactions to rapidly introduce molecular complexity. − For instance, we reported a Pt 1 /CeO 2 -promoted E -selective hydrogenation of α-diazoesters to synthesize biologically active 1 H -indazoles and their 15 N-labeled analogues, including anticancer lonidamine, adjudin, granisetron, and building blocks en route to gamendazole and bioactive alkaloids nigellicine and nigeglanine (Figure A) . The multifunctional indomethacin, an FDA-approved anti-inflammatory drug, can be successfully transformed to its long-chain aromatic ester derivative in 84% yield through sequential esterification and Suzuki coupling in the presence of Pd 1 –N 3 C 1 SAC .…”

“…A cavosonstat derivative and its 4-deuterated analogue (treatment of the F508del-CFTR mutation) were successfully synthesized through a one-step, Fe 1 -catalyzed cyclization (35% yield) instead of traditional Pd-catalyzed Suzuki coupling (46% in five-step) . A higher isolated yield (47%) was obtained via a Ru 3 O 2 /rGO-catalyzed Friedländer synthesis under the optimized condition . Likewise, Chen et al developed a phosphorus-coordinated Rh 1 SAC for the hydroformylation of olefins using synthesis gas (H 2 and CO) with high conversion (>99%) and high regioselectivity toward the branched aldehyde (>90%, or a branched to linear ratio of 13.3).…”

“…SACs have also demonstrated usefulness in complex reactions, although these reactions lack generic applicability so far. These include the diboration and hydroboration of alkynes and alkenes, hydroformylation, oxidative cyclization, and olefin isomerization–hydrosilylation, to produce a variety of valuable building blocks (e.g., boronic acid derivatives). , The unique properties of SACs in promoting such complex reactions pave the way for the synthesis and late-stage functionalization of pharmaceutical drugs, including lonidamine, Tamiflu, cavosonstat, , indomethacin, buclizine, ibuprofen, fendiline, cinacalcet hydrochloride, and many others − that are traditionally produced via homogeneous processes (Figure A).…”