Half-sandwich complexes of platinum group metals (Ir, Rh, Ru and Os) and some recent biological and catalytic applications

Journal of Organometallic Chemistry, Journal Year: 2018, Volume and Issue: 866, P. 123 - 143

Published: April 16, 2018

Language: Английский

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Effect of Ancillary Ligand in Cyclometalated Ru(II)–NHC-Catalyzed Transfer Hydrogenation of Unsaturated Compounds

Inorganic Chemistry, Journal Year: 2018, Volume and Issue: 57(23), P. 14582 - 14593

Published: Nov. 13, 2018

In an effort to develop efficient Ru(II)–NHC-based catalyst considering their stereoelectronic effect for hydride-transfer reaction, we found that the ancillary NHC ligand can play a significant role in its catalytic performance. This is demonstrated by comparing activity of two different types orthometalated precatalysts general formula [(p-cymene)(NHC)RuII(X)] (NHC = imidazolylidene-based ImNHC, compound 2a–c, or mesoionic triazolylidene-based tzNHC, 4) transfer hydrogenation carbonyl substrates. The electron-rich precatalyst, 2c, containing p-OMe-substituted performed significantly better than both unsubstituted complex 2a and p-CF3 substituted electron-poor 2b ketone reduction. Whereas bulky triazolylidene 4 was be superior aldehyde reduction precatalyst more suitable selective wide range aromatic aldimines amines. To best our knowledge, this first systematic study on tuning Ru(II)-catalyzed hydrogenations various unsaturated compounds with broad substrate scope.

Language: Английский

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Catalyst design for highly efficient carbon dioxide hydrogenation to formic acid under buffering conditions

Journal of Catalysis, Journal Year: 2020, Volume and Issue: 385, P. 1 - 9

Published: March 19, 2020

Language: Английский

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Donor‐Flexible Bis(pyridylidene amide) Ligands for Highly Efficient Ruthenium‐Catalyzed Olefin Oxidation

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 59(23), P. 8932 - 8936

Published: Feb. 26, 2020

An exceptionally efficient ruthenium-based catalyst for olefin oxidation has been designed by exploiting N,N'-bis(pyridylidene)oxalamide (bisPYA) as a donor-flexible ligand. The dynamic donor ability of the bisPYA ligand, imparted variable zwitterionic and neutral resonance structure contributions, paired with redox activity ruthenium provided catalytic Lemieux-Johnson-type oxidative cleavage olefins to efficiently prepare ketones aldehydes. complex significantly outperforms state-of-the-art systems displays extraordinary in this oxidation, reaching turnover frequencies 650 000 h-1 numbers several millions.

Language: Английский

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Cp*Ir complex bearing a flexible bridging and functional 2,2′-methylenebibenzimidazole ligand as an auto-tandem catalyst for the synthesis of N-methyl tertiary amines from imines via transfer hydrogenation/N-methylation with methanol

Journal of Catalysis, Journal Year: 2021, Volume and Issue: 402, P. 325 - 334

Published: Aug. 26, 2021

Language: Английский

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Pyridylidene Amines and Amides: Donor-Flexible Ligands for Catalysis

ACS Catalysis, Journal Year: 2023, Volume and Issue: 13(14), P. 9891 - 9904

Published: July 13, 2023

Ligands with flexible donor properties exhibit the unique ability to transition within continuum of neutral (L-type) and anionic (X-type) metal bonding in response their local electronic environment. This flexibility stabilizes transition-metal complexes unparalleled ways facilitates catalytic turnovers, especially when cycle features active center different oxidation states. Pyridylidene amines (PYEs) pyridylidene amides (PYAs) are examples nitrogen-based donor-flexible ligands. In past decade, application PYE PYA ligands catalysis has been growing, now include reactions such as hydrogen transfer reactions, water oxidation, CO2 utilization, among many others. Here we provide an overview these powerful ligands, including synthesis, properties, particular application─highlighting key ligand that impart high activity, well wide potential this rather underexplored system for diverse applications.

Language: Английский

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Highly β(Z)-Selective Hydrosilylation of Terminal Alkynes Catalyzed by Thiolate-Bridged Dirhodium Complexes

Organic Letters, Journal Year: 2018, Volume and Issue: 20(17), P. 5357 - 5361

Published: Aug. 28, 2018

A series of novel monothiolate-bridged dirhodium complexes, [Cp*Rh(μ-SR)(μ-Cl)2RhCp*][BF4] {Cp* = η5-C5Me5, R tertiary butyl (tBu), 1a; ferrocenyl (Fc), 1b; adamantyl (Ad), 1c} were designed and successfully synthesized, which can smoothly facilitate highly regioselective stereoselective hydrosilylation terminal alkynes to afford β(Z) vinylsilanes with good functional group compatibility. Furthermore, the hydride bridged complex [Cp*Rh(μ-StBu)(μ-Cl)(μ-H)RhCp*][BF4] (5) as a potential intermediate was obtained by reaction 1a excess HSiEt3.

Language: Английский

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Applying Le Chatelier's Principle for a Highly Efficient Catalytic Transfer Hydrogenation with Ethanol as the Hydrogen Source

ChemCatChem, Journal Year: 2018, Volume and Issue: 10(21), P. 4844 - 4848

Published: Sept. 10, 2018

Abstract While isopropanol or formic acid derivatives are mainly applied as hydrogen sources in catalytic transfer hydrogenation reactions, there only a few reports on the use of primary alcohols. In present communication we report that ecologically benign and cheap ethanol can be with ruthenium(II) is completely stable against moisture oxygen. Catalytic an equilibrium reaction. Therefore, rapid removal acetic aldehyde being formed product oxidation key for high conversions. The reaction shows broad substrate scope allows ketones, aldehydes imines.

Language: Английский

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Heteroditopic Ru(II)– and Ir(III)–NHC Complexes with Pendant 1,2,3-Triazole/Triazolylidene Groups: Stereoelectronic Impact on Transfer Hydrogenation of Unsaturated Compounds

Organometallics, Journal Year: 2019, Volume and Issue: 38(13), P. 2610 - 2623

Published: June 26, 2019

Imidazol-2-ylidene (ImNHC) and 1,2,3-traizol-5-ylidene (tzNHC) have been established as important classes of carbene ligands in homogeneous catalysis. To develop Ru(II)/Ir(III) complexes based on these ligand systems considering their electronic well steric profiles for hydride transfer reactions, we employed chelating featuring combinations ImNHC triazole-N or mesoionic tzNHC donors bridged by a CH2 spacer with possible modifications at triazole backbone. In general, synthesized Ru(II) were found to perform significantly better than analogous Ir(III) ketone aldimine reduction. Among the complexes, electron-rich 8/9 general formula [(p-cymene)(ImNHC–CH2–tzNHC)RuII(Cl)]BF4 two different (ImNHC tzNHC) appreciably reduction combination triazole-N-donor ([(p-cymene)(ImNHC–CH2–tz–N)RuII(Cl)]BF4; 4) explaining fine-tuning catalytic systems. No appreciable variation activity was observed between 8 9 having almost similar profiles. However, less bulky complex N-phenyl substituent is more suitable 8, N-3,5-dimethylphenyl that explains influence addition effect process.

Language: Английский

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Transition-Metal-Catalyzed Stereo- and Regioselective Hydrosilylation of Unsymmetrical Alkynes

Synthesis, Journal Year: 2021, Volume and Issue: 54(01), P. 49 - 66

Published: Aug. 23, 2021

Abstract Alkyne hydrosilylation is one of the most efficient methods for synthesis alkenyl silicon derivatives and has been a hot topic research decades. This short review summarizes progress in transition-metal-catalyzed stereo- regioselective unsymmetrical alkynes. Topics are discussed based on different types alkynes selectivities. 1 Introduction 2 Terminal Hydrosilylation 2.1 β-E Selectivity 2.2 β-Z 2.3 α-selectivity 3 Internal 3.1 Aryl–Alkyl Acetylenes 3.2 Alkyl–Alkyl 3.3 Alkynes with Polarized Substituents 4 Summary Outlook

Language: Английский

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