Manganese Alkyl Carbonyl Complexes: From Iconic Stoichiometric Textbook Reactions to Catalytic Applications

Accounts of Chemical Research, Год журнала: 2022, Номер 55(18), С. 2740 - 2751

Опубликована: Сен. 8, 2022

ConspectusThe activation of weakly polarized bonds represents a challenging, yet highly valuable process. In this context, precious metal catalysts have been used as reliable compounds for the rather inert last several decades. Nevertheless, base-metal complexes including cobalt, iron, or nickel are currently promising candidates substitution noble metals in order to develop more sustainable processes. past few years, manganese(I)-based were heavily employed efficient (de)hydrogenation reactions. However, vast majority these operate via metal–ligand bifunctionality already well implemented decades ago. Although high reactivity can be achieved various reactions, concept is often not applicable certain transformations due outer-sphere mechanisms. Account, we outline potential alkylated Mn(I)-carbonyl nonpolar and moderately polar E–H (E = H, B, C, Si) disclose our successful approach utilization field homogeneous catalysis. This involves rational design manganese hydrogenation reactions involving ketones, nitriles, carbon dioxide, alkynes. addition that, reduction alkenes by dihydrogen could series well-defined which was possible before. Furthermore, elucidate Mn-based hydrofunctionalization carbon–carbon multiple bonds. Our investigations unveiled novel insights into reaction pathways dehydrogenative silylation trans-1,2-diboration terminal alkynes, reported transition metals. Due catalyst design, under mild conditions. Delightfully, all bench-stable compounds. We took advantage fact that Mn(I) alkyl known undergo migratory insertion group CO ligand, yielding an unsaturated acyl intermediate. Hydrogen atom abstraction ligand then paves way active species variety catalytic proceed inner-sphere textbook well-known decades, application still its infancy. A brief historical overview manganese(I)–carbonyl provided, covering synthesis especially iconic stoichiometric transformations, e.g., carbonylation, intensively examined Calderazzo, Moss, others. An future applications defined will given, may inspire researchers development (base-)metal catalysts.

Язык: Английский

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Bis(N‐Heterocyclic Carbene) Manganese(I) Complexes: Efficient and Simple Hydrogenation Catalysts

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(35)

Опубликована: Июль 3, 2023

The use of bis(NHC) manganese(I) complexes 3 as catalysts for the hydrogenation esters was investigated. For that purpose, a series has been synthesized via an improved two step procedure utilizing bis(NHC)-BEt3 adducts. By applying with KHBEt3 additive, various aromatic and aliphatic were hydrogenated successfully at mild temperatures low catalyst loadings, highlighting efficiency novel catalytic system. versatility developed system further demonstrated by other substrate classes like ketones, nitriles, N-heteroarenes alkenes. Mechanistic experiments DFT calculations indicate inner sphere mechanism loss one CO ligand reveal role BEt3 cocatalyst.

Язык: Английский

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Hydrogenation of Esters Catalyzed by Bis(N-Heterocyclic Carbene) Molybdenum Complexes

ACS Catalysis, Год журнала: 2024, Номер 14(6), С. 4082 - 4092

Опубликована: Март 1, 2024

A series of Mo complexes bearing inexpensive bidentate bis(NHC) ligands have been synthesized and characterized by NMR IR spectroscopy as well single crystal XRD analysis. These proved to be efficient for the catalytic hydrogenation aliphatic aromatic esters (>35 examples) operating at low catalyst loadings (0.5–2 mol %) temperatures (80–120 °C). Various functional groups, e.g., C═C double bonds, nitriles, alcohols, tertiary amines, halides, acetals, heteroaromatic substrates, lactones, diesters, are tolerated optimal system. Based on spectroscopic investigations, control experiments DFT computations a non-bifunctional outer-sphere mechanism is proposed.

Язык: Английский

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Homogeneous Manganese-Catalyzed Hydrofunctionalizations of Alkenes and Alkynes: Catalytic and Mechanistic Tendencies

ACS Omega, Год журнала: 2022, Номер 7(42), С. 37008 - 37038

Опубликована: Окт. 11, 2022

In recent years, many manganese-based homogeneous catalytic precursors have been developed as powerful alternatives in organic synthesis. Among these, the hydrofunctionalizations of unsaturated C–C bonds correspond to outstanding ways afford compounds with more versatile functional groups, which are commonly used building blocks production fine chemicals and feedstock for industrial field. Herein, we present an account Mn-catalyzed alkenes alkynes main objective finding mechanistic tendencies that could serve a platform works come.

Язык: Английский

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An Adaptive Rhodium Catalyst to Control the Hydrogenation Network of Nitroarenes

Angewandte Chemie International Edition, Год журнала: 2022, Номер 61(36)

Опубликована: Июнь 27, 2022

An adaptive catalytic system that provides control over the nitroarene hydrogenation network to prepare a wide range of aniline and hydroxylamine derivatives is presented. This takes advantage delicate interplay between rhodium(III) center Lewis acidic borane introduced in secondary coordination sphere metal. The high chemoselectivity catalyst presence various potentially vulnerable functional groups its readiness be deployed at preparative scale illustrate practicality. Mechanistic studies density theory (DFT) methods were used shed light on mode functioning elucidate origin adaptivity. competition for interaction with boron solvent molecule substrate was found crucial When operating THF, reduction stops platform, whereas reaction can directed platform toluene.

Язык: Английский

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Theory-guided development of homogeneous catalysts for the reduction of CO₂to formate, formaldehyde, and methanol derivatives

Chemical Science, Год журнала: 2023, Номер 14(11), С. 2799 - 2807

Опубликована: Янв. 1, 2023

Computational volcano plots are used to predict selectivity in the context of (first-row) transition metal-catalyzed CO 2 reduction. The expected trends were tested experimentally and allowed for systematic improvement catalyst.

Язык: Английский

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Acceptorless Dehydrogenation of Methanol to Carbon Monoxide and Hydrogen using Molecular Catalysts

Angewandte Chemie International Edition, Год журнала: 2021, Номер 60(51), С. 26500 - 26505

Опубликована: Окт. 1, 2021

The acceptorless dehydrogenation of methanol to carbon monoxide and hydrogen was investigated using homogeneous molecular complexes. Complexes ruthenium manganese comprising the MACHO ligand framework showed promising activities for this reaction. complex [RuH(CO)(BH4 )(HN(C2 H4 PPh2 )2 )] (Ru-MACHO-BH) achieved up 3150 turnovers 9230 formation at 150 °C reaching pressures 12 bar when decomposition carried out in a closed vessel. Control experiments affirmed that metal mediates initial fast formaldehyde methyl formate followed by subsequent slow decarbonylation. Depending on catalyst reaction conditions, CO/H2 ratio gas mixture thus varies over broad range from almost pure stoichiometric limit 1:2.

Язык: Английский

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Manganese-Catalyzed Chemoselective Hydrosilylation of Nitroarenes: Sustainable Route to Aromatic Amines

Organic Letters, Год журнала: 2022, Номер 24(50), С. 9179 - 9183

Опубликована: Ноя. 22, 2022

Herein we report efficient catalytic hydrosilylations of nitroarenes to form the corresponding aromatic amines using a well-defined manganese(II)-NNO pincer complex with low catalyst loading (1 mol %) under solvent-free conditions. This base-metal-catalyzed hydrosilylation is an easy and sustainable alternative classical hydrogenation. A large variety bearing various functionalities were selectively transformed into in good yields. The potential utility present protocol was demonstrated by preparation commercial drug molecules.

Язык: Английский

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Air‐Stable Manganese NNS Pincer Complexes Enable Ketone Reduction at Room Temperature

ChemCatChem, Год журнала: 2024, Номер 16(9)

Опубликована: Янв. 22, 2024

Abstract A series of air‐stable Mn complexes bearing NNS pincer ligands have been synthesized and fully characterized. The activity the as (transfer) hydrogenation catalysts was investigated in detail, a variety ketones (>20 examples) were converted to corresponding secondary alcohols at room temperature. synthetic applicability this class is demonstrated by tolerance several functional groups including halides, primary amines, nitriles, esters, nitro‐groups. Moreover, optimal catalytic system 5c displayed high chemoselectivity presence other reducible such alkynes. Competitive experiments with analogous bidentate NN complex 8 indicated decoordination hemilabile thioether‐moiety during formation catalytically active hydrido species.

Язык: Английский

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Hydrogenolysis of Urethanes and Ureas Catalyzed by Manganese Complex Supported by Bidentate PN Ligand

Organometallics, Год журнала: 2024, Номер 43(9), С. 924 - 928

Опубликована: Апрель 18, 2024

Hydrogenolysis of less reactive carbonyl compounds such as urethanes and ureas is a challenging but promising transformation to utilize new chemical feedstocks, plastic waste carbon dioxide fixation products. In these transformations, pincer-type complexes consisting Ru Mn have been intensively investigated catalyst design with bidentate ligand systems has rarely explored. We report here the synthesis complex supported by PN phosphino pyrrolido coordination sites, molecular structure which fully characterized. The catalyzed hydrogenolysis ureas. case 1,3-diphenylurea, formanilide was obtained product. addition, present did not promote hydrogenation carboxamides, showing unique reactivity that preferentially reduces over in contrast general order compounds.

Язык: Английский

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