Electrocatalytic Ammonia Oxidation by a Low-Coordinate Copper Complex

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(46), P. 21136 - 21145

Published: Nov. 9, 2022

Molecular catalysts for ammonia oxidation to dinitrogen represent enabling components utilize as a fuel and/or source of hydrogen. Ammonia requires not only the breaking multiple strong N-H bonds but also controlled N-N bond formation. We report novel β-diketiminato copper complex [iPr2NNF6]CuI-NH3 ([CuI]-NH3 (2)) robust electrocatalyst NH3 in acetonitrile under homogeneous conditions. Complex 2 operates at moderate overpotential (η = 700 mV) with TOFmax 940 h-1 determined from CV data 1.3 M NH3-MeCN solvent. Prolonged (>5 h) potential electrolysis (CPE) reveals stability and robustness catalyst electrocatalytic Detailed mechanistic investigations indicate that electrochemical [CuI]-NH3 forms {[CuII]-NH3}+ (4), which undergoes deprotonation by excess form reactive copper(II)-amide ([CuII]-NH2, 6) unstable toward formation give dinuclear hydrazine [CuI]2(μ-N2H4). Electrochemical studies reveal diammine [CuI](NH3)2 (7) high concentration part {[CuII](NH3)2}+/[CuI](NH3)2 redox couple is electrocatalytically inactive. DFT analysis much higher thermodynamic barrier four-coordinate {[CuII](NH3)2}+ (8) copper(II) amide [CuII](NH2)(NH3) (9) (ΔG 31.7 kcal/mol) compared three-coordinate provide parent [CuII]-NH2 18.1 susceptible coupling [CuI]2(μ-N2H4) -11.8 kcal/mol).

Language: Английский

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Oxidative Substitution of Organocopper(II) by a Carbon-Centered Radical

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(33), P. 23555 - 23565

Published: Aug. 8, 2024

Copper-catalyzed coupling reactions of alkyl halides are believed to prominently involve copper(II) species and radicals as pivotal intermediates, with their exact interaction mechanism being the subject considerable debate. In this study, a visible light-responsive fluoroalkylcopper(III) complex, [(terpy)Cu(CF3)2(CH2CO2tBu)] Trans-1, was designed explore mechanism. Upon exposure blue LED irradiation, Trans-1 undergoes copper–carbon bond homolysis, generating Cu(II) carbon-centered radicals, where radical then recombines intermediate, resulting in formation Cis-1, Cis isomer Trans-1. Beyond this, well-defined fluoroalkylcopper(II) intermediate ligated sterically hindered ligand isolated underwent full characterization electronic structure studies. The collective experimental, computational, spectroscopic findings work strongly suggest that organocopper(II) engages via an "oxidative substitution" mechanism, which is likely operational pathway for copper-catalyzed C–H trifluoromethylation reactions.

Language: Английский

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Unified approaches in transition metal catalyzed C(sp³)–H functionalization: recent advances and mechanistic aspects

Chemical Society Reviews, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

Direct alteration of unactivated C–H bonds organic building blocks.

Language: Английский

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Recent Advances in Theoretical Studies on Cu-Mediated Bond Formation Mechanisms Involving Radicals

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(4), P. 2429 - 2454

Published: Feb. 1, 2024

Copper-catalyzed radical transformations establish a powerful toolkit to construct versatile complex organic compounds. The copper-mediated bond formation step of radicals plays critical role in controlling chemo- and stereoselectivity copper-catalyzed transformation reactions. This involves three possible pathways: ion-type formation, substitution, reductive elimination. review highlights the recent advances theoretical studies on mechanisms models selectivity Cu-mediated radical-involved providing general mechanistic comprehension this key elementary copper catalysis.

Language: Английский

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Three Component syn‐1,2‐Arylmethylation of Internal Alkynes**

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(12)

Published: Jan. 26, 2023

A Pd-catalyzed three-component syn-1,2-arylmethylation of internal alkynes (ynamides/yne-acetates/alkynes) is described. The readily available and bench stable coupling partners iodo-arenes, methyl boronic acid are successfully used in this strategy to access the methyl-containing tetra-substituted olefins; scope broad showing excellent functional-group tolerance. Notably, transformation regio- as well stereoselective. biologically relevant motifs (BRM) bearing iodo-arenes ynamides also for late-stage alkynes. Aryl-alkylation, aryl-trideuteriomethylation, alkynyl-methylation, alkenyl-methylation presented. Me-substituted alkenes further transformed into synthetically important β-amino-indenones α-fluoro-α'-methyl ketones.

Language: Английский

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Cross‐selective Deoxygenative Coupling of Aliphatic Alcohols: Installation of Methyl Groups including Isotopic Labels by Nickel Catalysis

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(24)

Published: April 12, 2024

Abstract Nickel‐catalyzed cross‐electrophile coupling reactions of two aliphatic alcohol derivatives remain a challenge. Herein, we report nickel‐catalyzed reductive methylation reaction mesylates with methyl tosylate. This provides straightforward access to compounds bearing groups from alkyl derivatives. Isotopically labelled substrates and reagents can be employed in the provide perdeuterated 13 C‐labelled products. transformation achieved by employing stoichiometric Mn reductant or electrochemically. Additionally, mechanistic experiments show that iodides are key intermediates which undergo stereoablative via radical intermediates.

Language: Английский

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Catalytic undirected methylation of unactivated C(sp3)−H bonds suitable for complex molecules

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: Sept. 27, 2024

Language: Английский

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“tert-Butyl peroxybenzoate (TBPB)-mediated copper-catalyzed C(sp3)-H methylation of 4-thiazolidinone”

Tetrahedron, Journal Year: 2025, Volume and Issue: unknown, P. 134590 - 134590

Published: March 1, 2025

Language: Английский

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Cu/photoredox-catalyzed decarboxylative radical C(sp3)-C(sp3) cross-coupling reactions

Science China Chemistry, Journal Year: 2023, Volume and Issue: 66(10), P. 2858 - 2862

Published: Sept. 7, 2023

Language: Английский

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Selective Radical Transfer in a Series of Nonheme Iron(III) Complexes

Inorganic Chemistry, Journal Year: 2023, Volume and Issue: 62(43), P. 17830 - 17842

Published: Oct. 19, 2023

A series of nonheme iron complexes, FeIII(BNPAPh2O)(Lax)(Leq) (Lax/eq = N3–, NCS–, NCO–, and Cl–) have been synthesized using the previously reported BNPAPh2O– ligand. The ferrous analogs FeII(BNPAPh2O)(Lax) (Lax NCO–) were also prepared. complexes structurally characterized single crystal X-ray diffraction, which shows that all FeIII are six-coordinate, with one anionic ligand (Lax) in H-bonding axial site other (Leq) equatorial plane, cis to Lax reaction FeIII(BNPAPh2O–)(Lax)(Leq) Ph3C• is selectively transferred each case. selectivity trend emerges •N3 most favored for transfer case carbon radical, whereas Cl• least favored. NCO NCS ligands showed an intermediate propensity radical transfer, > NCO. overall order N3 Cl. In addition, we demonstrated has a small effect on governing product by non-H-bonded (DPAPh2O–). This study demonstrates inherent nonhydroxo-ligated iron(III) could be useful efforts synthetic (bio)catalytic C–H functionalization.

Language: Английский

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