Utilization of ruthenium(0) for σ-bond activation: Formation of organoruthenium complexes and emergence of their catalytic activity via in situ Ru-C bond cleavage

Journal of Organometallic Chemistry, Journal Year: 2025, Volume and Issue: unknown, P. 123567 - 123567

Published: Feb. 1, 2025

Language: Английский

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Highly Efficient N-Heterocyclic Carbene/Ruthenium Catalytic Systems for the Acceptorless Dehydrogenation of Alcohols to Carboxylic Acids: Effects of Ancillary and Additional Ligands

Catalysts, Journal Year: 2019, Volume and Issue: 10(1), P. 10 - 10

Published: Dec. 19, 2019

The transition-metal-catalyzed alcohol dehydrogenation to carboxylic acids has been identified as an atom-economical and attractive process. Among various catalytic systems, Ru-based systems have the most accessed investigated ones. With our growing interest in discovery of new Ru catalysts comprising N-heterocyclic carbene (NHC) ligands for dehydrogenative reactions alcohols, we designed prepared five NHC/Ru complexes ([Ru]-1–[Ru]-5) bearing different ancillary NHC ligands. Moreover, effects additional on with KOH were thoroughly explored, followed by screening other parameters. Accordingly, a highly active system, which is composed [Ru]-5 combined precursor L5, was discovered, affording variety acid products efficient manner. Gratifyingly, extremely low loading (125 ppm) maximum TOF value until now (4800) obtained.

Language: Английский

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Complementing Pyridine‐2,6‐bis(oxazoline) with Cyclometalated N‐Heterocyclic Carbene for Asymmetric Ruthenium Catalysis

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 59(30), P. 12392 - 12395

Published: May 12, 2020

Abstract A strategy for expanding the utility of chiral pyridine‐2,6‐bis(oxazoline) (pybox) ligands asymmetric transition metal catalysis is introduced by adding a bidentate ligand to modulate electronic properties and induction. Specifically, ruthenium(II) pybox fragment combined with cyclometalated N‐heterocyclic carbene (NHC) generate catalysts enantioselective nitrenoid chemistry, including ring contraction 2H‐azirines (up 97 % ee 2000 TON) C(sp 3 )−H aminations 50 TON).

Language: Английский

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Probing Electronic Properties of Triazolylidenes through Mesoionic Selones, Triazolium Salts, and Ir-Carbonyl-Triazolylidene Complexes

Organometallics, Journal Year: 2020, Volume and Issue: 39(24), P. 4557 - 4564

Published: Nov. 23, 2020

Understanding and quantifying the electronic properties of ligands is important both from a fundamental point view also for their applications in various branches chemistry. In this contribution, we present comparative study on donor/acceptor 10 different triazolylidene-type mesoionic carbene (MICs), with aim investigating deciphering effects substituents such MIC ligands. Data 77Se NMR chemical shifts triazoline selones, 1JC-H coupling constants corresponding triazolium salts, Tolman parameters (TEP) Ir-CO complexes are compared contrasted. The data collected work show that spread TEP relatively narrow to be able significantly differentiate between donor MICs. selones other hand broad spread, it principle well-suited understand π-accepting MICs as function substituents. However, method can have complications which discussed work. DFT calculations presented light shifts. Additionally, first example AuI complex class whose utility has remained underexplored transition metal

Language: Английский

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Cyclometalated Ruthenium Pincer Complexes as Catalysts for the α‐Alkylation of Ketones with Alcohols

Chemistry - A European Journal, Journal Year: 2020, Volume and Issue: 26(27), P. 6050 - 6055

Published: Jan. 27, 2020

Ruthenium PNP pincer complexes bearing supplementary cyclometalated C,N-bound ligands have been prepared and fully characterized for the first time. By replacing CO H- as ancillary in such complexes, additional electronic steric modifications of this topical class catalysts are possible. The advantages new demonstrated general α-alkylation ketones with alcohols following a hydrogen autotransfer protocol. Herein, various aliphatic benzylic were applied green alkylating agents aromatic, heteroaromatic or substituents well cyclic ones. Mechanistic investigations revealed that during catalysis, Ru carboxylate predominantly formed whereas neither nor CN ligand released from catalyst significant amounts.

Language: Английский

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Methylene-Linked Bis-NHC Half-Sandwich Ruthenium Complexes: Binding of Small Molecules and Catalysis toward Ketone Transfer Hydrogenation

Organometallics, Journal Year: 2021, Volume and Issue: 40(6), P. 792 - 803

Published: March 9, 2021

The complex [Cp*RuCl(COD)] reacts with LH2Cl2 (L = bis(3-methylimidazol-2-ylidene)) and LiBun in tetrahydrofuran at 65 °C furnishing the bis-carbene derivative [Cp*RuCl(L)] (2). This compound NaBPh4 MeOH under dinitrogen to yield labile dinitrogen-bridged [{Cp*Ru(L)}2(μ-N2)][BPh4]2 (4). ligand 4 is readily replaced by a series of donor molecules leading corresponding cationic complexes [Cp*Ru(X)(L)][BPh4] (X MeCN 3, H2 6, C2H4 8a, CH2CHCOOMe 8b, CHPh 9). Attempts recrystallize from MeNO2/EtOH solutions led isolation nitrosyl [Cp*Ru(NO)(L)][BPh4]2 (5), which was structurally characterized. allenylidene [Cp*Ru═C═C═CPh2(L)][BPh4] (10) also obtained, it prepared reaction 2 HC≡CC(OH)Ph2 60 °C. Complexes 4, 6 are efficient catalyst precursors for transfer hydrogenation broad range ketones. dihydrogen has proven particularly effective, reaching TOF values up 455 h–1 loadings 0.1% mol, high functional group tolerance on reduction scope aryl aliphatic ketones alcohols.

Language: Английский

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Gram-scale synthesis of carboxylic acids via catalytic acceptorless dehydrogenative coupling of alcohols and hydroxides at an ultralow Ru loading

Applied Catalysis A General, Journal Year: 2021, Volume and Issue: 630, P. 118443 - 118443

Published: Nov. 27, 2021

Language: Английский

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Cyclometalated (NNC)Ru(ii) complex catalyzed β-methylation of alcohols using methanol

Dalton Transactions, Journal Year: 2022, Volume and Issue: 51(11), P. 4354 - 4365

Published: Jan. 1, 2022

Indolyl fragment containing phenanthroline based new ligands and their corresponding Ru(II) complexes were synthesized fully characterized by various spectroscopic techniques. The catalytic activity of these newly cyclometalated (NNC)Ru(II) was explored towards the β-methylation alcohols using methanol. Notably, displayed superior reactivity compared to (NNN)Ru(II) complexes. Utilizing this strategy, a wide range primary, secondary, aliphatic straight chain selectively methylated. This protocol further employed for methylation few natural products gram scale synthesis β-methylated alcohols. A series control experiments kinetic studies performed understand plausible reaction mechanism.

Language: Английский

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Recent Advances in the Syntheses and Catalytic Applications of Homonuclear Ru‐, Rh‐, and Ir‐Complexes of C_NHC^C Cyclometalated Ligands

Chemistry - A European Journal, Journal Year: 2021, Volume and Issue: 27(67), P. 16581 - 16600

Published: Sept. 1, 2021

In the past few decades, chemistry of cyclometalated species has gained momentum with increased applications in several areas scientific developments. Cyclometalation reactions result formation stable metallacycles through generation metal-carbon covalent bonds by activating unreactive Csp2 -H or Csp3 bonds. The extra stability enhances their applicability scopes especially area homogeneous catalysis. recent research development this area, NHC ligands (strong σ-donor and generally, weak π-acceptor) have been found to be one most suitable candidates for intramolecular C-H activation process which leads species. growth cyclometalation that started late 20th century is still continuing various examples derived transition metal-based complexes came into picture. As covering all reported literatures (includes mainly metals) will exceed limits minireview, we restricted ourselves (2015 - May 2021) common Ru-, Rh-, Ir-based CNHC ^C catalytic conversions such as transfer hydrogenation, amidation, oxidation alcohols, annulations, so forth.

Language: Английский

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New half-sandwich (η6-p-cymene)ruthenium(II) complexes with benzothiazole hydrazone Schiff base ligand: Synthesis, structural characterization and catalysis in transamidation of carboxamide with primary amines

Journal of Organometallic Chemistry, Journal Year: 2020, Volume and Issue: 929, P. 121555 - 121555

Published: Oct. 7, 2020

Language: Английский

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