First-Row Transition Metal (De)Hydrogenation Catalysis Based On Functional Pincer Ligands

Chemical Reviews, Journal Year: 2018, Volume and Issue: 119(4), P. 2681 - 2751

Published: Dec. 31, 2018

The use of 3d metals in de/hydrogenation catalysis has emerged as a competitive field with respect to "traditional" precious metal catalyzed transformations. introduction functional pincer ligands that can store protons and/or electrons expressed by metal-ligand cooperativity and ligand redox-activity strongly stimulated this development conceptual starting point for rational catalyst design. This review aims at providing comprehensive picture the utilization first-row transition hydrogenation dehydrogenation related synthetic concepts relying on these such hydrogen borrowing methodology. Particular emphasis is put implementation relevance cooperating redox-active within mechanistic scenarios.

Language: Английский

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Strategies and mechanisms of metal–ligand cooperativity in first-row transition metal complex catalysts

Chemical Society Reviews, Journal Year: 2020, Volume and Issue: 49(24), P. 8933 - 8987

Published: Jan. 1, 2020

The use of metal–ligand cooperation (MLC) by transition metal bifunctional catalysts has emerged at the forefront homogeneous catalysis science.

Language: Английский

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Homogeneous manganese-catalyzed hydrogenation and dehydrogenation reactions

Chem, Journal Year: 2020, Volume and Issue: 7(5), P. 1180 - 1223

Published: Dec. 9, 2020

Language: Английский

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Homogeneous and heterogeneous catalytic reduction of amides and related compounds using molecular hydrogen

Nature Communications, Journal Year: 2020, Volume and Issue: 11(1)

Published: Aug. 4, 2020

Abstract Catalytic hydrogenation of amides is great interest for chemists working in organic synthesis, as the resulting amines are widely featured natural products, drugs, agrochemicals, dyes, etc. Compared to traditional reduction using (over)stoichiometric reductants, direct molecular hydrogen represents a greener approach. Furthermore, amide highly versatile transformation, since not only higher (obtained by C–O cleavage), but also lower and alcohols, or amino alcohols C–N cleavage) can be selectively accessed fine tuning reaction conditions. This review describes most recent advances area H 2 exclusively molecularly defined homogeneous well nano-structured heterogeneous catalysts, with special focus on catalyst development synthetic applications.

Language: Английский

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Manganese-catalyzed hydrogenation, dehydrogenation, and hydroelementation reactions

Chemical Society Reviews, Journal Year: 2022, Volume and Issue: 51(11), P. 4386 - 4464

Published: Jan. 1, 2022

The emerging field of organometallic catalysis has shifted towards research on Earth-abundant transition metals due to their ready availability, economic advantage, and novel properties. In this case, manganese, the third most abundant transition-metal in Earth's crust, emerged as one leading competitors. Accordingly, a large number molecularly-defined Mn-complexes been synthesized employed for hydrogenation, dehydrogenation, hydroelementation reactions. regard, catalyst design is based three pillars, namely, metal-ligand bifunctionality, ligand hemilability, redox activity. Indeed, developed catalysts not only differ chelating atoms they possess but also working principles, thereby different turnover numbers product molecules. Hence, critical assessment molecularly defined manganese terms atoms, reaction conditions, mechanistic pathway, significant. Herein, we analyze complexes catalytic activity, versatility allow multiple transformations routes convert substrates target This article will be helpful get significant insight into design, aiding design.

Language: Английский

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Robust and efficient hydrogenation of carbonyl compounds catalysed by mixed donor Mn(I) pincer complexes

Nature Communications, Journal Year: 2021, Volume and Issue: 12(1)

Published: Jan. 4, 2021

Abstract Any catalyst should be efficient and stable to implemented in practice. This requirement is particularly valid for manganese hydrogenation catalysts. While representing a more sustainable alternative conventional noble metal-based systems, catalysts are prone degrade under catalytic conditions once operation temperatures high. Herein, we report highly Mn(I)-CNP pre-catalyst which gives rise the excellent productivity (TOF° up 41 000 h −1 ) stability (TON 200 000) catalysis. system enables near-quantitative of ketones, imines, aldehydes formate esters at loadings as low 5–200 p.p.m. Our analysis points crucial role activation step performance system. employing alkoxide bases can ultimately provide catalytically competent species hydrogen atmosphere, Mn(I) with hydride donor promoters, e.g. KHBEt 3 , dramatically improves eliminates induction times associated slow activation.

Language: Английский

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Low pressure amide hydrogenation enabled by magnetocatalysis

Nature Communications, Journal Year: 2025, Volume and Issue: 16(1)

Published: April 11, 2025

Language: Английский

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Mechanistic Studies of Hydride Transfer to Imines from a Highly Active and Chemoselective Manganate Catalyst

Journal of the American Chemical Society, Journal Year: 2019, Volume and Issue: 141(29), P. 11677 - 11685

Published: June 28, 2019

We introduce a highly active and chemoselective manganese catalyst for the hydrogenation of imines. The has large scope, can reduce aldimines ketimines, tolerates variety functional groups, among them sensitive examples such as an olefin, ketone, nitriles, nitro aryl iodo substituent or benzyl ether. could investigate transfer step between imines hydride complex in detail. found that double deprotonation ligand is essential excess base does not lead to higher rate step. identified actual K–Mn-bimetallic species obtain structure K–Mn formed after by X-ray analysis. NMR experiments indicate well-defined reaction, which first order imine, bimetallic (K–Mn) hydride, independent from concentration potassium base. propose outer-sphere mechanism protons do seem be involved rate-determining step, leading transiently negatively charged nitrogen atom substrate reacts rapidly with HOtBu (2-methylpropan-2-ol) produce amine. This based on several observations, no dependency reaction concentration, observable amide complex, high constant conducted Hammett study. Furthermore, hydrogen catalytic cycle was experimentally probed monitored subsequent quantitative regeneration H2.

Language: Английский

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Manganese Catalyzed Hydrogenation of Carbamates and Urea Derivatives

Journal of the American Chemical Society, Journal Year: 2019, Volume and Issue: 141(33), P. 12962 - 12966

Published: July 31, 2019

We report the hydrogenation of carbamates and urea derivatives, two most challenging carbonyl compounds to be hydrogenated, catalyzed for first time by a complex an earth-abundant metal. The reaction these CO2-derived compounds, manganese pincer complex, yields methanol in addition amine alcohol, which makes this methodology sustainable alternative route conversion CO2 methanol, involving base-metal catalyst. Moreover, proceeds under mild pressure (20 bar). Our observations support mechanism Mn–H complex. A plausible catalytic cycle is proposed based on informative mechanistic experiments.

Language: Английский

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Phosphine-Free Well-Defined Mn(I) Complex-Catalyzed Synthesis of Amine, Imine, and 2,3-Dihydro-1H-perimidine via Hydrogen Autotransfer or Acceptorless Dehydrogenative Coupling of Amine and Alcohol

Organometallics, Journal Year: 2019, Volume and Issue: 38(8), P. 1815 - 1825

Published: April 12, 2019

The application of nontoxic, earth-abundant transition metals in place costly noble is a paramount goal catalysis and especially interesting if the air- moisture-stable ligand scaffold used. Herein, we report synthesis amines/imines directly from alcohol amines via hydrogen autotransfer or acceptorless dehydrogenation catalyzed by well-defined phosphine-free Mn complexes. Both imines can be obtained same set alcohols using catalyst, only tuning reaction conditions. amount nature base are found to highly important aspect for observed selectivity. primary secondary have been employed as substrates N-alkylation reaction. As highlight, showed chemoselective resveratrol derivatives. Furthermore, Mn-catalyzed dehydrogenative structurally 2,3-dihydro-1H-perimidines has also demonstrated. Density functional theory calculations were carried out model path calculate profile.

Language: Английский

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