The oligomeric ruthenium-based water oxidation catalyst, Ru(bda), is known to be experimentally anchored on graphitic surfaces through CH-π stacking interactions between the auxiliary bda ([2,2'-bipyridine]-6,6'-dicarboxylate) ligand bonded to ruthenium and the hexagonal rings of the surface. This anchoring provides control over their molecular coverage and enables efficient catalysis of water oxidation to dioxygen. The oligomeric nature of the molecule offers multiple anchoring sites at the surface, greatly enhancing the overall stability of the hybrid catalyst-graphitic surface anode through dynamic bonding. However, the impact of this dynamic anchoring on the overall catalytic mechanism is still a topic of debate. In this study, a crucial proton-coupled electron transfer event in the catalytic cycle is investigated using DFT-based molecular dynamics simulations plus metadynamics. The CH-π stacking anchoring plays a critical role not only in stabilizing this hybrid system but also in facilitating the proton-coupled electron transfer event with possible vibronic couplings between the anchoring bonds motion and charge fluctuations at the catalyst - graphitic surface interface. Furthermore, this computational investigation displays the presence of a quartet spin state intermediate that can lead to the experimentally observed and thermodynamically more stable doublet spin state.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1002/cplu.202400082 | DOI Listing |
J Am Chem Soc
January 2025
Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1, 8093 Zürich, Switzerland.
Organic redox systems that can undergo oxidative and reductive (ambipolar) electron transfer are elusive yet attractive for applications across synthetic chemistry and energy science. Specifically, the use of ambipolar redox systems in proton-coupled electron transfer (PCET) reactions is largely unexplored but could enable "switchable" reactivity wherein the uptake and release of hydrogen atoms are controlled using a redox stimulus. Here, we describe the synthesis and characterization of an ambipolar functionalized terthiophene (TTH) bearing methyl thioether and phosphine oxide groups that exhibits switchable PCET reactivity.
View Article and Find Full Text PDFACS Phys Chem Au
January 2025
University of Duisburg-Essen, Faculty of Chemistry, Theoretical Catalysis and Electrochemistry, Universitätsstraße 5, Essen 45141, Germany.
The direct conversion of dinitrogen to nitrate is a dream reaction to combine the Haber-Bosch and Ostwald processes as well as steam reforming using electrochemistry in a single process. Regrettably, the corresponding nitrogen oxidation (NOR) reaction is hampered by a selectivity problem, since the oxygen evolution reaction (OER) is both thermodynamically and kinetically favored in the same potential range. This opens the search for the identification of active and selective NOR catalysts to enable nitrate production under anodic reaction conditions.
View Article and Find Full Text PDFACS Cent Sci
January 2025
College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China.
Multicomponent reactions (MCRs), highly sought-after methods to produce atom-, step-, and energy-economic organic syntheses, have been developed extensively. However, catalytic asymmetric MCRs, especially those involving radical species, remain largely unexplored owing to the difficulty in stereoselectively regulating the extraordinarily high reactivity of open-shell radical species. Herein, we report a conceptually novel catalytic asymmetric three-component radical cascade reaction of readily accessible glycine esters, α-bromo carbonyl compounds and 2-vinylcyclopropyl ketones via synergistic photoredox/Brønsted acid catalysis, in which three sequential C-C (σ/π/σ) bond-forming events occurred through a radical addition/ring-opening/radical-radical coupling protocol, affording an array of valuable enantioenriched unnatural α-amino acid derivatives bearing two contiguous stereogenic centers and an alkene moiety in moderate to good yield with high diastereoselectivity, excellent enantioselectivity and good -dominated geometry under mild reaction conditions.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea.
A series of Ni complexes bearing a redox and acid-base noninnocent tetraamido macrocyclic ligand, H-(TAML-4) {H-(TAML-4) = 15,15-dimethyl-5,8,13,17-tetrahydro-5,8,13,17-tetraaza-dibenzo[]cyclotridecene-6,7,14,16-tetraone}, with formal oxidation states of Ni, Ni, and Ni were synthesized and characterized structurally and spectroscopically. The X-ray crystallographic analysis of the Ni complexes revealed a square planar geometry, and the [Ni(TAML-4)] complex with the formal oxidation state of Ni was characterized to be [Ni(TAML-4)] with the oxidation state of the Ni ion and the one-electron oxidized TAML-4 ligand, TAML-4. The Ni oxidation state and the TAML-4 radical cation ligand, TAML-4, were supported by X-ray absorption spectroscopy and density functional theory calculations.
View Article and Find Full Text PDFSmall
January 2025
College of Materials Science and Engineering, Sichuan University, Chengdu, 610065, China.
The transition metal single atoms (SAs)-based catalysts with M-N coordination environment have shown excellent performance in electrocatalytic reduction of CO, and they have received extensive attention in recent years. However, the presence of SAs makes it very difficult to efficiently improve the coordination environment. In this paper, a method of direct high-temperature pyrolysis carbonization of ZIF-8 adsorbed with Ni and Fe ions is reported for the synthesis of Ni SAs and FeN nanoparticles (NPs) supported by the N-doped carbon (NC) hollow nanododecahedras (HNDs) with nanotubes (NTs) on the surface (Ni SAs/FeN NPs@NC-HNDs-NTs).
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!