A Tailored Versatile and Efficient NHC‐Based NNC‐Pincer Manganese Catalyst for Hydrogenation of Polar Unsaturated Compounds

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(23)

Опубликована: Апрель 7, 2023

The reactivity of metal-hydride complexes can be harnessed by the modification ancillary ligands. With aim improving hydride-donor ability key Mn-H intermediate and reducing steric hindrance, we herein report rational design a versatile efficient NHC-based NNC-pincer Mn catalyst for hydrogenation reactions. This newly developed exhibited higher activity than corresponding NNP-pincer owing to its reduced hindrance enhanced σ-bonding orbital energy level through π-antibonding interaction. Using this highly active catalyst, rich array polar unsaturated compounds (>80 examples) including esters, N-heteroarenes, amides, carbonates, urea derivatives, were successfully hydrogenated under relatively mild conditions. work represents rare example general phosphine-free Mn-catalyzed system.

Язык: Английский

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Cobalt-catalyzed dehydrogenative cross-coupling reaction: Selective access to dihydrosiloxanes, hydrosiloxanes and functionalized silsesquioxanes

Journal of Catalysis, Год журнала: 2023, Номер 423, С. 1 - 9

Опубликована: Апрель 27, 2023

Disclosed is a mild, scalable, and chemoselective cross-dehydrogenative functionalization protocol for the construction of Si−O−Si moieties under cobalt catalysis. The reaction has broad scope can be used to synthesize wide range silicon building blocks, including challenging dihydrosiloxanes functionalized silsesquioxanes. Most importantly, results are placed into context by benchmarking with state-of-the-art methods. Remarkably, utilized PNP-Co catalyst enables development further synthetic strategies such as one-pot sequential silanolysis/alcoholysis process or unprecedented dehydrocoupling between germanol hydrosilane.

Язык: Английский

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Hydrogenation of Carboxylic Esters Catalyzed by Phosphine-Free Bis-N-heterocyclic Carbene Manganese Complexes

Organometallics, Год журнала: 2023, Номер 42(14), С. 1832 - 1838

Опубликована: Июнь 5, 2023

As an earth-abundant transition metal, manganese is now recognized as a good candidate for the development of catalysts reduction-type reactions. It often associated with noninnocent tridentate ligand, featuring acidic NH moiety. We report here that simple bidentate and phosphine-free bis-N-heterocyclic ligand in complex [Mn(bis-NHCMes)(CO)3Br] could catalyze hydrogenation carboxylic esters presence KBHEt3 activator at 100–120 °C under 50 bar H2 1 mol % catalyst loading 2-Me-THF.

Язык: Английский

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Understanding the Factors That Influence the Antioxidant Activity of Manganosalen Complexes with Neuroprotective Effects

Antioxidants, Год журнала: 2024, Номер 13(3), С. 265 - 265

Опубликована: Фев. 22, 2024

Manganosalen complexes are a class of catalytic antioxidants with beneficial effects against different neurological disorders according to various in vitro and vivo studies. The interest the factors that determine their antioxidant activity is based on fact they key achieving more efficient models. In this work, we report set new manganosalen complexes, thoroughly characterized solid state solution by techniques. chelating Schiff base ligands used were prepared from condensation substituted hydroxybenzaldehydes 1,2-diaminoethane 1,3-diaminopropane. models was tested through superoxide dismutase catalase probes conjunction studies about neuroprotective human SH-SY5Y neuroblastoma cells an oxidative stress model. ability scavenge excess reactive oxygen species (ROS) varied depending models, which also yielded improvements cell survival. An assessment affect oxidant for these others previously reported, revealed major influence structural versus redox properties complexes.

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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A Phosphine-Oxide Cobalt(II) Complex and Its Catalytic Activity Studies toward Alcohol Dehydrogenation Triggered Direct Synthesis of Imines and Quinolines

Inorganic Chemistry, Год журнала: 2024, Номер 63(21), С. 9786 - 9800

Опубликована: Май 13, 2024

Herein, a new pincer-like amino phosphine donor ligand, H2L1, and its phosphine-oxide analog, H2L2, were synthesized. Subsequently, cobalt(II) complexes 1 2 synthesized by the reaction of anhydrous Co(II)Cl2 with ligands H2L1 respectively. The fully characterized various physicochemical spectroscopic characterization techniques. Finally, identity was confirmed single crystal X-ray structure determination. ligand containing complex converted to oxide in air acetonitrile solution. Both investigated as precatalysts for alcohol dehydrogenation-triggered synthesis imines air. more efficient than 1. A wide array alcohols amines successfully reacted mild condition result good excellent yields. Precatalyst also highly varieties quinolines As H2L2 has side arms that can be deprotonated, we base (KOtBu) promoted deprotonation events studies DFT calculations. These have shown mono amine arm attached pyridine is quite feasible, leads dearomatized pyridyl ring 2a. mechanistic investigations catalytic reaction, combination experimental computational studies, suggested complex, 2a acted an active catalyst. proceeded through hydride transfer pathway. activation barrier this step calculated 26.5 kcal/mol, which consistent temperature under aerobic conditions. Although are explored such reactions, ligand-containing still unexplored.

Язык: Английский

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Manganese catalysed reduction of nitriles with amine boranes

Catalysis Science & Technology, Год журнала: 2024, Номер 14(17), С. 4843 - 4847

Опубликована: Янв. 1, 2024

The room temperature reduction of various nitriles using amine boranes catalysed by a manganese( i ) alkyl complex is described. Based on experimental findings, plausible mechanistic scenario presented.

Язык: Английский

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Base- and Additive-Free Carbon Dioxide Hydroboration to Methoxyboranes Catalyzed by Non-Pincer-Type Mn(I) Complexes

ACS Catalysis, Год журнала: 2023, Номер 13(8), С. 5236 - 5244

Опубликована: Март 31, 2023

Well-defined, bench stable Mn(I) non-pincer-type complexes were tested as earth-abundant transition metal catalysts for the selective reduction of CO2 to boryl-protected MeOH in presence pinacolborane (HBpin). Essentially, quantitative yields obtained under mild reaction conditions (1 bar CO2, 60 °C), without need any base or additives, alkylcarbonyl bis(phosphine) fac-[Mn(CH2CH2CH3)(dippe)(CO)3] [Mn1, dippe = 1,2-bis(diisopropylphosphino)ethane] and [Mn(dippe)(CO)2{(μ-H)2(Bpin)}] (Mn4), that is by bench-stable precatalyst Mn1 with HBpin via elimination butanal. Preliminary mechanistic details a combination NMR experiments monitoring catalytic reactions.

Язык: Английский

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Hydrogenation of Terminal Alkenes Catalyzed by Air‐Stable Mn(I) Complexes Bearing an N‐Heterocyclic Carbene‐Based PCP Pincer Ligand

Chemistry - A European Journal, Год журнала: 2023, Номер 30(4)

Опубликована: Окт. 10, 2023

Efficient hydrogenations of terminal alkenes with molecular hydrogen catalyzed by well-defined bench stable Mn(I) complexes containing an N-heterocyclic carbene-based PCP pincer ligand are described. These reactions environmentally benign and atom economic, implementing inexpensive, earth abundant non-precious metal catalyst. A range aromatic aliphatic were efficiently converted into alkanes in good to excellent yields. The hydrogenation proceeds at 100 °C catalyst loadings 0.25-0.5 mol %, 2.5-5 % base (KO

Язык: Английский

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Recent developments in alkene hydrosilylation utilizing manganese catalysts

Tetrahedron Letters, Год журнала: 2023, Номер 132, С. 154798 - 154798

Опубликована: Окт. 15, 2023

Язык: Английский

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