Advances in the Synthesis and Applications of N-Heterocyclic Carbene Metal Complexes with a Focus on the Weak Base Route

Organometallics, Journal Year: 2023, Volume and Issue: 42(19), P. 2692 - 2730

Published: Sept. 21, 2023

N-heterocyclic carbene (NHC) ligands have evolved from being simple lab curiosities to tertiary phosphine mimics finally take center stage as unique supporting in organometallic chemistry, homogeneous catalysis, and more recently medicinal chemistry materials science applications. Some of these aspects are presented here a perspective researchers that been fascinated by the area for quite some time.

Language: Английский

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Recent advances of mesoionic N-heterocyclic olefins

Dalton Transactions, Journal Year: 2022, Volume and Issue: 51(24), P. 9191 - 9198

Published: Jan. 1, 2022

This Perspective article highlights the recent development of mesoionic N-heterocyclic olefins (mNHOs), where exo-cyclic olefinic carbon is not bonded to strongly electron-withdrawing groups. The unquenched basicity and nucleophilicity make mNHOs strong σ-donors enable unique reactivity patterns.

Language: Английский

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Visible-Light-Promoted Iridium(III)-Catalyzed Acceptorless Dehydrogenation of N-Heterocycles at Room Temperature

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(10), P. 6238 - 6245

Published: May 10, 2022

An effective visible-light-promoted iridium(III)-catalyzed hydrogen production from N-heterocycles is described. A single iridium complex constitutes the photocatalytic system playing a dual task, harvesting visible-light and facilitating C-H cleavage H2 formation at room temperature without additives. The presence of chelating C-N ligand combining mesoionic carbene along with an amido functionality in IrIII essential to attain transformation. Furthermore, also efficient catalyst for thermal reverse process under mild conditions, positioning itself as proficient candidate liquid organic carrier technologies (LOHCs). Mechanistic studies support light-induced Ir-H intermediate operating mode complex.

Language: Английский

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1,3‐Imidazole‐Based Mesoionic Carbenes and Anionic Dicarbenes: Pushing the Limit of Classical N‐Heterocyclic Carbenes

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(36)

Published: May 3, 2023

Classical N-heterocyclic carbenes (NHCs) featuring the carbene center at C2-position of 1,3-imidazole framework (i.e. C2-carbenes) are well acknowledged as very versatile neutral ligands in molecular materials sciences. The efficiency and success NHCs diverse areas is essentially attributed to their persuasive stereoelectronics, particular potent σ-donor property. with unusual C4 (or C5) position, so-called abnormal (aNHCs) or mesoionic (iMICs), however superior σ-donors than C2-carbenes. Hence, iMICs have substantial potential sustainable synthesis catalysis. main obstacle this direction rather demanding synthetic accessibility iMICs. aim review article highlight recent advances, particularly by author's research group, accessing stable iMICs, quantifying properties, exploring applications In addition, viability use vicinal C4,C5-anionic dicarbenes (ADCs), also based on an framework, presented. As will be apparent following pages, ADCs hold potentials pushing limit classical enabling access conceptually new main-group heterocycles, radicals, catalysts, sets, more.

Language: Английский

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Pushing the Upper Limit of Nucleophilicity Scales by Mesoionic N‐Heterocyclic Olefins

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(40)

Published: Aug. 4, 2023

A series of mesoionic, 1,2,3-triazole-derived N-heterocyclic olefins (mNHOs), which have an extraordinarily electron-rich exocyclic CC-double bond, was synthesized and spectroscopically characterized, in selected cases by X-ray crystallography. The kinetics their reactions with arylidene malonates, ArCH=C(CO2 Et)2 , gave zwitterionic adducts, were investigated photometrically THF at 20 °C. resulting second-order rate constants k2 (20 °C) correlate linearly the reported electrophilicity parameters E malonates (reference electrophiles), thus providing nucleophile-specific N sN mNHOs according to correlation lg °C)=sN (N+E). With 21

Language: Английский

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Application of first-row transition metal complexes bearing 1,2,3-triazolylidene ligands in catalysis and beyond

Chemical Society Reviews, Journal Year: 2024, Volume and Issue: 53(12), P. 6322 - 6344

Published: Jan. 1, 2024

Triazole-derived N-heterocyclic carbenes, available via click reactions, are versatile ligands for first-row transition metals, leading to complexes with attractive photochemical properties and catalytic activity, some defining the state-of-the-art.

Language: Английский

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Palladium(II) Triazolylidene/Phosphine Complex as an Efficient Catalyst for Suzuki–Miyaura Coupling Reactions in Water

ChemistrySelect, Journal Year: 2025, Volume and Issue: 10(15)

Published: April 1, 2025

Abstract Palladium(II) complexes with a combination of mesoionic carbene (MIC) and phosphine ligands have received huge importance in recent times due to their catalytic benefits. Two new mononuclear Pd II pyridine or PPh 3 as ancillary were synthesized starting from the corresponding triazolium salt. These possess bulky Dipp substitution at N1 position bromophenyl C4 triazolylidene moiety. An in‐depth spectroscopic analysis ( 1 H, 13 C{ H}, 2D NMR) has been executed for these complexes. The molecular structure palladium(II) complex having MIC trans‐ each other established single crystal XRD measurement. Both aforementioned utilized highly active precatalysts Suzuki–Miyaura coupling reactions water. findings unequivocally demonstrate supremacy MIC/phosphine over MIC/pyridine complex.

Language: Английский

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Electronic Coupling in 1,2,3-Triazole Bridged Ferrocenes and Its Impact on Reactive Oxygen Species Generation and Deleterious Activity in Cancer Cells

Inorganic Chemistry, Journal Year: 2022, Volume and Issue: 61(25), P. 9650 - 9666

Published: June 14, 2022

Mixed-valence (MV) binuclear ferrocenyl compounds have long been studied as models for testing theories of electron transfer and in attempts to design molecular-scale electronic devices (e.g., molecular wires). In contrary that, far less attention has paid MV ferrocenes anticancer agents. Herein, we discuss the synthesis six 1,2,3-triazole combined (spectro)electrochemical, paramagnetic resonance (EPR), computational, activity studies. Our synthetic approach was based on copper-catalyzed 1,3-dipolar azide–alkyne cycloaddition reaction enabled us obtain one step bearing either one, two, or three entities linked common core. Thus, two series complexes were obtained, which pertain derivatives 3′-azido-3′-deoxythymidine (AZT) 3-azidopropionylferrocene, respectively. Based experimental theoretical data, mono-oxidized species corresponding AZT trinuclear 3-azidopropionylferrocene categorized class II mixed-valence according classification proposed by Robin Day. Of importance is observation that these are more active against human A549 H1975 non-small-cell lung cancer cells than their congeners, do not show characteristics. Moreover, competes surpasses, dependent cell line, reference drugs such cisplatin, tamoxifen, 5-fluorouracil. The most from entire thymidine derivative with lowest IC50 value 5 ± 2 μM cells. major mechanism antiproliferative investigated reactive oxygen generation This hypothesis substantiated EPR spin-trapping experiments decreased presence N-acetyl cysteine (NAC) free-radical scavenger.

Language: Английский

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A naphthalene-based heterobimetallic triazolylidene Ir^III/Pd^II complex: regioselective to regiospecific C–H activation, tandem catalysis and a copper-free Sonogashira reaction

Dalton Transactions, Journal Year: 2023, Volume and Issue: 52(8), P. 2272 - 2281

Published: Jan. 1, 2023

Heterobimetallic complexes featuring mesoionic carbene (MIC) donor ligands are gaining enormous popularity in tandem catalysis owing to the combined action of two different metal centers during catalysis. A rare version heterobimetallic PdII/IrIII complex possessing a cyclometalated ligand is presented along with analogous homodinuclear PdII complex. sterically controlled regiospecific cyclometalation towards formation six-membered ring over five-membered has been performed using naphthalene-based bis-MIC platform. The interplay between regioselective vs. C-H bond activation for synthesis IrIII also demonstrated corresponding naphthyl-derived mono-imidazolylidene ligand. Both and have characterized standard spectroscopic techniques including 1H, 13C{1H}, 2D correlation NMR spectroscopy ESI mass spectrometry. structure established by single crystal XRD. employed as pre-catalyst Suzuki-Miyaura/transfer hydrogenation reaction homobimetallic successfully catalyst both Sonogashira coupling α-arylation 1-methyl-2-oxindole.

Language: Английский

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Investigation of Huisgen's Noble metal catalyst click reaction mechanism for the synthesis of 1,4-disubstituted 1,2,3-triazoles

Molecular Catalysis, Journal Year: 2024, Volume and Issue: 566, P. 114412 - 114412

Published: Aug. 2, 2024

Language: Английский

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