Cu/Fe-Catalyzed Carbon-Carbon and Carbon-Heteroatom Cross-Coupling Reactions

Panda, Niranjan

doi:10.4172/2161-0401.1000130

Cited by 10 publications

(6 citation statements)

References 180 publications

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“…Generally, this reaction is an attractive method for the formation of C-heteroatom and C–C bonds in organic synthesis [38]. This reaction of condensation is usually conducted at temperature as high as 200 °C, often in the presence of stoichiometric amounts of copper(I) catalyst and is reserved only for the active aryl halides [39]. However, a small amount of organic additive (e.g., 1,10-phenanthroline, diamines, aminoacids, diols, etc.)…”

Section: Resultsmentioning

confidence: 99%

Ullmann Reactions of Carbon Nanotubes—Advantageous and Unexplored Functionalization toward Tunable Surface Chemistry

et al. 2019

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We demonstrate Ullmann-type reactions as novel and advantageous functionalization of carbon nanotubes (CNTs) toward tunable surface chemistry. The functionalization routes comprise O-, N-, and C-arylation of chlorinated CNTs. We confirm the versatility and efficiency of the reaction allowing functionalization degrees up to 3.5 mmol g−1 by applying both various nanotube substrates, i.e., single-wall (SWCNTs) and multi-wall CNTs (MWCNTs) of various chirality, geometry, and morphology as well as diverse Ullmann-type reagents: phenol, aniline, and iodobenzene. The reactivity of nanotubes was correlatable with the nanotube diameter and morphology revealing SWCNTs as the most reactive representatives. We have determined the optimized conditions of this two-step synthetic protocol as: (1) chlorination using iodine trichloride (ICl3), and (2) Ullmann-type reaction in the presence of: copper(I) iodide (CuI), 1,10-phenanthroline as chelating agent and caesium carbonate (Cs2CO3) as base. We have analyzed functionalized CNTs using a variety of techniques, i.e., scanning and transmission electron microscopy, energy dispersive spectroscopy, thermogravimetry, comprehensive Raman spectroscopy, and X-ray photoelectron spectroscopy. The analyses confirmed the purely covalent nature of those modifications at all stages. Eventually, we have proved the elaborated protocol as exceptionally tunable since it enabled us: (a) to synthesize superhydrophilic films from—the intrinsically hydrophobic—vertically aligned MWCNT arrays and (b) to produce printable highly electroconductive pastes of enhanced characteristics—as compared for non-modified and otherwise modified MWCNTs—for textronics.

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Section: Resultsmentioning

confidence: 99%

Ullmann Reactions of Carbon Nanotubes—Advantageous and Unexplored Functionalization toward Tunable Surface Chemistry

et al. 2019

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“…Among these, mixed Fe/Cu complexes were proved to be active in a wide range of relevant processes, e.g. in Fischer–Tropsch synthesis, the water-gas shift reaction, semihydrogenation of alkynes, CO 2 reduction, C–H borylation, small-molecule activation, and carbon–carbon and carbon–heteroatom coupling reactions . Keeping in mind the prominent metallic character of germanium itself, one could expect a high catalytic activity of Cu/Fe/Ge complexes.…”

Section: Introductionmentioning

confidence: 99%

“…in Fischer−Tropsch synthesis, 7 water-gas shift reaction, 8 semihydrogenation of alkynes, 9 CO 2 reduction, 10 C−H borylation, 11 small-molecule activation, 12 and carbon−carbon and carbon−heteroatom coupling reactions. 13 Keeping in mind the prominent metallic character of germanium itself, one could expect a high catalytic activity of Cu/Fe/Ge complexes. In accord with this, we were interested in the synthesis of mixed Fe/Cu germsesquioxanes and the application of such products in catalysis.…”

Section: ■ Introductionmentioning

confidence: 99%

Heptanuclear Fe₅Cu₂-Phenylgermsesquioxane containing 2,2′-Bipyridine: Synthesis, Structure, and Catalytic Activity in Oxidation of C–H Compounds

et al. 2017

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A new representative of an unusual family of metallagermaniumsesquioxanes, namely the heterometallic cagelike phenylgermsesquioxane (PhGeO)CuFe(O)OH(PhGe)O(bipy) (2), was synthesized and structurally characterized. Fe(III) ions of the complex are coordinated by oxa ligands: (i) cyclic (PhGeO) and acyclic (PhGeO) germoxanolates and (ii) O and (iii) HO moieties. In turn, Cu(II) ions are coordinated by both oxa (germoxanolates) and aza ligands (2,2'-bipyridines). This "hetero-type" of ligation gives in sum an attractive pagoda-like molecular architecture of the complex 2. Product 2 showed a high catalytic activity in the oxidation of alkanes to the corresponding alkyl hydroperoxides (in yields up to 30%) and alcohols (in yields up to 100%) and in the oxidative formation of benzamides from alcohols (catalyst loading down to 0.4 mol % in Cu/Fe).

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“…A mixture of Fe 2 SO 4 and CuCl 2 catalyzes the oxidation and isomerization of alkene-containing organoperoxides, yielding ketone products, with the postulated mechanism showing the two metal ions participating in tandem . In terms of cooperative catalysis, mixtures of Cu and Fe (in the form of salts, complexes, or nanoparticles) have been used to successfully promote cross-coupling reactions, including those that form new C–C bonds, − C–O bonds, , C–S bonds, and also N-arylation. − In contrast, there is surprisingly little use of mixtures of metals and their complexes in cooperative catalysis for the direct functionalization of hydrocarbon C–H bonds. In one example, amination of an allylic C–H bond was achieved by a palladium acetate catalyst but only when a Cr III catalyst was also present to aminate the palladium allyl intermediate …”

Section: Introductionmentioning

confidence: 99%

Earth-Abundant Mixed-Metal Catalysts for Hydrocarbon Oxygenation

et al. 2018

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The oxygenation of aliphatic and aromatic hydrocarbons using earth-abundant Fe and Cu catalysts and "green" oxidants such as hydrogen peroxide is becoming increasingly important to atom-economical chemical processing. In light of this, we describe that dinuclear Cu complexes of pyrrolic Schiff-base macrocycles, in combination with ferric chloride (FeCl), catalyze the oxygenation of π-activated benzylic substrates with hydroperoxide oxidants at room temperature and low loadings, representing a novel design in oxidation catalysis. Mass spectrometry and extended X-ray absorption fine structure analysis indicate that a cooperative action between Cu and Fe occurs, most likely because of the interaction of FeCl or FeCl with the dinuclear Cu macrocycle. Voltammetric measurements highlight a modulation of both Cu and Fe redox potentials in this adduct, but electron paramagnetic resonance spectroscopy indicates that any Cu-Fe intermetallic interaction is weak. High ketone/alcohol product ratios, a small reaction constant (Hammett analysis), and small kinetic isotope effect for H-atom abstraction point toward a free-radical reaction. However, the lack of reactivity with cyclohexane, oxidation of 9,10-dihydroanthracene, oxygenation by the hydroperoxide MPPH (radical mechanistic probe), and oxygenation in dinitrogen-purge experiments indicate a metal-based reaction. Through detailed reaction monitoring and associated kinetic modeling, a network of oxidation pathways is proposed that includes "well-disguised" radical chemistry via the formation of metal-associated radical intermediates.

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Cu/Fe-Catalyzed Carbon-Carbon and Carbon-Heteroatom Cross-Coupling Reactions

Cited by 10 publications

References 180 publications

Ullmann Reactions of Carbon Nanotubes—Advantageous and Unexplored Functionalization toward Tunable Surface Chemistry

Ullmann Reactions of Carbon Nanotubes—Advantageous and Unexplored Functionalization toward Tunable Surface Chemistry

Heptanuclear Fe₅Cu₂-Phenylgermsesquioxane containing 2,2′-Bipyridine: Synthesis, Structure, and Catalytic Activity in Oxidation of C–H Compounds

Earth-Abundant Mixed-Metal Catalysts for Hydrocarbon Oxygenation

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Cu/Fe-Catalyzed Carbon-Carbon and Carbon-Heteroatom Cross-Coupling Reactions

Cited by 10 publications

References 180 publications

Ullmann Reactions of Carbon Nanotubes—Advantageous and Unexplored Functionalization toward Tunable Surface Chemistry

Ullmann Reactions of Carbon Nanotubes—Advantageous and Unexplored Functionalization toward Tunable Surface Chemistry

Heptanuclear Fe5Cu2-Phenylgermsesquioxane containing 2,2′-Bipyridine: Synthesis, Structure, and Catalytic Activity in Oxidation of C–H Compounds

Earth-Abundant Mixed-Metal Catalysts for Hydrocarbon Oxygenation

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Heptanuclear Fe₅Cu₂-Phenylgermsesquioxane containing 2,2′-Bipyridine: Synthesis, Structure, and Catalytic Activity in Oxidation of C–H Compounds