Ruthenacycles and Iridacycles as Transfer Hydrogenation Catalysts

Molecules, Год журнала: 2021, Номер 26(13), С. 4076 - 4076

Опубликована: Июль 3, 2021

In this review, we describe the synthesis and use in hydrogen transfer reactions of ruthenacycles iridacycles. The review limits itself to metallacycles where a ligand is bound bidentate fashion either ruthenium or iridium via carbon-metal sigma bond, as well dative bond from heteroatom an N-heterocyclic carbene. Pincer complexes fall outside scope. Described are applications (asymmetric) hydrogenation aldehydes, ketones, imines, reductive aminations. Oxidation reactions, i.e., classical Oppenauer oxidation, which reverse hydrogenation, dehydrogenations oxidations with oxygen, described. Racemizations alcohols secondary amines also catalyzed by

Язык: Английский

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Synthesis and antagonistic evaluation of fluorinated imidazolium salt [1-(2,6-diisopropylphenyl)-3-(2-fluoro-benzyl)-1H-imidazol-3-ium bromide] against significant phytopathogens in agriculture

Journal of Fluorine Chemistry, Год журнала: 2024, Номер 274, С. 110259 - 110259

Опубликована: Фев. 1, 2024

Язык: 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, Год журнала: 2021, Номер 630, С. 118443 - 118443

Опубликована: Ноя. 27, 2021

Язык: Английский

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Zeolitic imidazolate framework-8 as an efficient and facile heterogeneous catalyst for the acceptorless alcohol dehydrogenation to carboxylates

Journal of Catalysis, Год журнала: 2022, Номер 417, С. 202 - 212

Опубликована: Дек. 7, 2022

Язык: Английский

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Acceptorless dehydrogenation of alcohols to carboxylic acids by palladium nanoparticles supported on NiO: delving into metal–support cooperation in catalysis

Dalton Transactions, Год журнала: 2022, Номер 51(25), С. 9922 - 9934

Опубликована: Янв. 1, 2022

In this work, we have developed a simple NiO-supported Pd nanocatalyst (Pd@NiO) for oxidant-free dehydrogenative oxidation of primary alcohols to carboxylic acids along with hydrogen gas as byproduct. The catalyst has been characterized by techniques like XRD, HRTEM, SEM-EDX, XPS and ICP-AES. nanostructured Pd@NiO material showed excellent activity outperformed the free NiO or nanoparticles supported on silica/carbon catalyst, which could be attributed synergistic effect NiO. A diverse range aromatic aliphatic efficiently converted their corresponding carboxylates in high yields loading low 0.08 mol%. Notably, highly challenging biomass derived heterocyclic such furfuryl alcohol piperonyl can also acids. Moreover, our convert benzyl benzoic acid gram scale 89% yield. Interestingly, H2 liberated reaction used substrate hydrogenation 3a 4a 65% is reusable no significant decrease was observed after six cycles. kinetic study revealed that followed first-order kinetics rate constant k = 1.47 × 10-4 s-1, under optimized conditions. extent reactivity different functionalities towards dehydrogenation investigated using Hammett plot showing good linearity.

Язык: 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, Год журнала: 2021, Номер 27(67), С. 16581 - 16600

Опубликована: Сен. 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.

Язык: Английский

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Role of ancillary ligands in selectivity towards acceptorless dehydrogenation versus dehydrogenative coupling of alcohols and amines catalyzed by cationic ruthenium(ii)–CNC pincer complexes

Dalton Transactions, Год журнала: 2023, Номер 52(43), С. 15878 - 15895

Опубликована: Янв. 1, 2023

An unexpected reversal in catalytic activity for acceptorless dehydrogenative coupling compared to alcohol dehydrogenation has been observed using a series of cationic Ru(II)-CNC pincer complexes with different ancillary ligands. In continuation our study 1a-6a, new bulky N-wingtips [Ru(CNCiPr)(CO)(PPh3)Br]PF6 (1b), [Ru(CNCCy)(CO)(PPh3)Cl]PF6 (1c), [Ru(CNCCy)(CO)(PPh3)H]PF6 (2c), [Ru(CNCiPr)(PPh3)2Cl]PF6 (3b), [Ru(CNCCy)(PPh3)2Cl]PF6 (3c), [Ru(CNCiPr)(PPh3)2H]PF6 (4b), [Ru(CNCCy)(PPh3)2H]PF6 (4c), [Ru(CNCiPr)(DMSO)2Cl]PF6 (6b), and [Ru(CNCCy)(DMSO)2Cl]PF6 (6c) [CNCR = 2,6-bis(1-alkylimidazol-2-ylidene)-pyridine] have synthesized the activities their N-methyl analogues transfer hydrogenation cyclohexanone benzyl alcohol. Furthermore, all utilized as catalysts reaction amines. While were found be line previously trend based on ligands (CO > COD DMSO PPh3), reaction, containing PPh3 performed better CO Based NMR mass investigation reactions, plausible mechanism suggested explain difference its during reaction. substrate scope wide range amines explored, including synthesizing some pharmaceutically important imines. All characterized by various spectroscopic techniques, structures 4b 6b confirmed single-crystal X-ray diffraction technique.

Язык: Английский

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Dehydrogenation of primary alcohols to carboxylic acids in water catalyzed by PNHN-manganese(I) carbonyl complexes

Journal of Catalysis, Год журнала: 2024, Номер 436, С. 115601 - 115601

Опубликована: Июнь 12, 2024

Язык: Английский

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Half-Sandwich Iridium Complexes: A Recyclable and Stable Catalyst for Dehydrogenation of Alcohols to Carboxylic Acids

Inorganic Chemistry, Год журнала: 2024, Номер 63(29), С. 13311 - 13320

Опубликована: Июль 8, 2024

A series of acylhydrazone-based

Язык: Английский

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Pd-PEPPSI Catalyzed Dehydrogenative Oxidation of Alcohols to Carboxylic Acids: An Experimental and Theoretical Study

Organometallics, Год журнала: 2024, Номер unknown

Опубликована: Авг. 30, 2024

Herein, we report syntheses of two new PEPPSI-type (PEPPSI: pyridine enhanced precatalyst preparation stabilization and initiation) palladium N-heterocyclic carbene (NHC) complexes, [PdBr2(NHC)Py] (1,2) [NHC = 3-(3,5-dimethoxybenzyl)-1-(4-methoxyphenyl)-1H-imidazol-3-ium-2-ide (L1); 1-(4-methoxyphenyl)-3-(naphthalen-1-ylmethyl)-1H-imidazol-3-ium-2-ide (L2)], explored their catalytic potentials for alcohol dehydrogenation (AD) reactions. The molecular structures the complexes were determined by single-crystal X-ray analysis. Both could catalyze AD reactions; however, under similar conditions, sterically bulky naphthyl-containing complex 2 showed slightly better activity than 3,5-dimethoxy benzyl-containing 1. A range alcohols, including relatively challenging aliphatic biomass-based converted to corresponding carboxylates in moderate-to-excellent yields. Interestingly, our catalyst is also effective gram-scale synthesis benzoic acid with a catalyst-to-substrate ratio 1:3333, exhibiting turnover number (TON) 2466. comprehensive mechanistic investigation using density functional theory (DFT) has been made. Four possible reaction pathways computationally examined: one dissociative pathway where both Py Br– ligands leave coordination site, associative either or ligand leaves another proceeds through intermediary ester formation. calculated energy profile studies revealed that formation most favorable among four pathways.

Язык: Английский

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