CO2 Reduction to CO on an Iron-Porphyrin Complex with Crown-Ether Appended Cation-Binding Site

Dalton Transactions, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

In this work a novel CO 2 reduction catalyst is discussed that contains an iron-porphyrin complex with K + ion bound in the second coordination sphere, which assists efficient proton delivery.

Language: Английский

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Nonheme Manganese-Catalyzed Oxidative N-Dealkylation of Tertiary Amides: Manganese(IV)-Oxo Aminopyridine Cation Radical Species and Hydride Transfer Mechanism

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: March 19, 2025

The development of efficient and practical N-dealkylation reactions stands as a longstanding objective in synthetic chemistry. Inspired by the oxidative mediated heme nonheme metalloenzymes, we disclose biomimetic catalysis that utilizes manganese complex bearing anthryl-appended aminopyridine ligand hydrogen peroxide (H2O2) terminal oxidant. A variety Weinreb amides cyclic aliphatic amines are efficiently transformed into valuable methyl hydroxamates ω-amino acids through C-N bond cleavage. Mechanistic studies, including density functional theory (DFT) calculations, reveal manganese(IV)-oxo cation radical species, which is formed via bromoacetic acid-assisted heterolytic O-O cleavage presumed manganese(III)-hydroperoxo species subsequent intramolecular electron transfer (ET) from anthryl group to center, active intermediate initiates reactions; this process reminiscent iron(III)-hydroperoxo porphyrin intermediates (Cpd 0) form iron(IV)-oxo π-cation radicals I) responsible for diverse selective oxidation reactions. Moreover, it revealed activation C-H adjacent nitrogen atom proceeds hydride (HT) mechanism, involves concerted asynchronous proton-coupled (PCET), followed an ET process. Thus, study reports first instance catalytic tertiary amides, such amines, Cpd I-like initial HT pathway.

Language: Английский

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Mechanism of the Oxidative Ring-Closure Reaction during Gliotoxin Biosynthesis by Cytochrome P450 GliF

International Journal of Molecular Sciences, Journal Year: 2024, Volume and Issue: 25(16), P. 8567 - 8567

Published: Aug. 6, 2024

During gliotoxin biosynthesis in fungi, the cytochrome P450 GliF enzyme catalyzes an unusual C-N ring-closure step while also aromatic ring is hydroxylated same reaction cycle, which may have relevance to drug synthesis reactions biotechnology. However, as details of mechanism are still controversial, no applications been developed yet. To resolve and gain insight into steps leading ring-closure, we ran a combination molecular dynamics density functional theory calculations on structure reactivity tested range possible mechanisms, pathways models. The show that, rather than hydrogen atom transfer from substrate Compound I, initial proton transition state followed by fast electron en route radical intermediate, hence non-synchronous abstraction takes place. intermediate then reacts OH rebound form biradical through between centers, gives products. Interestingly, energetics mechanisms appear little affected addition polar groups model predict that can be catalyzed other isozymes bind substrate. Alternative pathways, such pathway starting with electrophilic attack arene epoxide, high energy ruled out.

Language: Английский

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Unraveling Chlorite Oxidation Pathways in Equatorially Heteroatom-Substituted Nonheme Iron Complexes

ACS Organic & Inorganic Au, Journal Year: 2024, Volume and Issue: 4(6), P. 673 - 680

Published: Sept. 20, 2024

The first-coordination sphere of catalysts is known to play a crucial role in reaction mechanisms, but details how equatorial ligands influence the reactivity remain unknown. Heteroatom ligated position iron centers nonheme metalloenzymes modulates structure and reactivity. To investigate impact heteroatom substitution on chlorite oxidation, we synthesized characterized three novel mononuclear iron(II) complexes with pentadentate bispidine scaffold. These feature systematic substitutions at ligand framework where pyridine group replaced NMe

Language: Английский

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Heteromultimetallic Platform for Enhanced C–H Bond Activation: Aluminum-Incorporated Dicopper Complex Mimicking Cu-ZSM-5 Structure and Oxidative Reactivity

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(43), P. 29810 - 29823

Published: Oct. 18, 2024

Bimetallic complexes have sparked interest across various chemical disciplines, driving advancements in research. Recent this field shed light on complex reactions metalloenzymes and unveiled new transformations. Two primary types of bimetallic platforms emerged: (1) systems where both metals actively participate reactivity, (2) one metal mediates the reaction while other regulates reactivity. This study introduces a novel multinucleating ligand platform capable integrating systems. To demonstrate significance platform, we synthesized unique dicopper incorporating aluminum its coordination environment. serves as first structural model for active site copper-based zeolites, highlighting role hydrogen atom abstraction Comparative studies oxidative C–H bond activation revealed that inclusion significantly alters thermodynamic force (by −11 kcal mol–1) modifies proton-coupled electron-transfer mechanism, resulting 14-fold rate increase. Both computational experimental data support high modularity offering approach to fine-tune reactivity complexes.

Language: Английский

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Unraveling the Geometry-Driven C═C Epoxidation and C–H Hydroxylation Reactivity of Tetra-Coordinated Nonheme Iron(IV)–Oxo Complexes

Inorganic Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: July 19, 2024

The electronic structure and reactivity of tetra-coordinated nonheme iron(IV)-oxo complexes have remained unexplored for years. recent synthesis a closed-shell complex [(quinisox)Fe

Language: Английский

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