Presence Of CuCl Research Articles

Oxidation of Alkanes with Dioxygen Induced by Visible Light and Cu(II) and Fe(III) Chlorides.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Selective Synthesis of Fused Cyclooctatetraenes by [4 + 4] Coupling Between Two Different Diene Units.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Oxidation of Alkanes with Dioxygen Induced by Visible Light and Cu(II) and Fe(III) Chlorides

Abstract Cyclohexane and adamantane were oxidized in acetonitrile with dioxygen to the corresponding alcohols and ketones under irradiation of visible light in the presence of CuCl2 or FeCl3 catalyst. Fairly good selectivity of the products was attained with CuCl2: ca. 50% for cyclohexane and 75% for adamantane at over 50% conversion. Alkyl hydroperoxides were detected during the reactions in 10% and 25% amounts of the products at maximum for the cyclohexane oxidation with CuCl2 and FeCl3, respectively. Moreover, the products were overoxidized by the present system at comparable or slower rates than the alkanes. Other features of the reaction, such as the rate of oxygen uptake and carbon dioxide liberation, isotope effect, and radical inhibitor effect, were also investigated.

Copper(I)‐Catalyzed Addition of Trifluoromethylated Benzyl Radicals Derived from Aryltrifluoroethyl Bromides to Terminal Olefins.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Reaction of catalytic olefination of hydrazones with polyhaloalkanes. Investigation of alkene formation chemoselectivity

Hydrazones of carbonyl compounds at treatment with polyhaloalkanes in the presence of CuCl as catalyst are converted into substituted alkenes with formation of a new C=C bond.

Novel efficient synthesis of dibromoalkenes. A first example of catalytic olefination of aliphatic carbonyl compounds.

A new simple and efficient one pot transformation of various aliphatic carbonyl compounds to the corresponding dibromoalkenes is described. A wide range of hydrazones of aldehydes and ketones, prepared in situ, were easily converted into dibromoalkenes by treatment with carbon tetrabromide in the presence of CuCl. The reaction proceeds under mild conditions to give the target products in good to high yields.

Catalytic olefination of carbonyl compounds. Effect of the structure of the carbonyl compound on the reaction

The mechanism of the novel reaction of catalytic olefination of carbonyl compounds was studied. The reaction involves the transformation of hydrazones of aromatic aldehydes and ketones into the corresponding dichloroalkenes and symmetrical azines by the treatment with carbon tetrachloride in the presence of CuCl as a catalyst. The stability of intermediate diazoalkanes is the main factor determining the direction of the reaction. In the case of sufficiently stable diazoalkanes, other products can be formed under the reaction conditions along with the products of catalytic olefination.

Low-temperature growth of carbon nanotubes

Multiwalled carbon nanotubes filled with Cu metal, Cu2O, and CuCl are produced by poly(vinyl alcohol) carbonization in the presence of CuCl or CuCl2 . The structure and composition of the reaction products are analyzed by x-ray photoelectron spectroscopy, transmission electron microscopy, and selected-area electron diffraction. The carbonization products are found to contain, along with carbon nanotubes, carbon-encapsulated spherical metallic nanoparticles and carbon fibers. A simplified mechanism of nanotube growth is proposed which differs from the well-known high-temperature mechanism.

Palladium-Catalyzed Intramolecular Oxidative Alkylation of Unactivated Olefins

Reaction of 5,5-dimethyl-8-nonene-2,4-dione catalyzed by PdCl2(CH3CN)2 (5 mol %) in the presence of CuCl2 (2.5 equiv) at room temperature for 3 h formed 2-acetyl-3,6,6-trimethyl-2-cyclohexenone in 96% isolated yield. Palladium-catalyzed intramolecular oxidative alkylation tolerated a range of substitution and was applicable to the synthesis of spirobicyclic compounds and to the cyclization of zeta-alkenyl beta-keto esters.

Selective synthesis of fused cyclooctatetraenes by [4 + 4] coupling between two different diene units.

In the presence of CuCl and 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone, the [4 + 4] coupling between zirconacyclopentadienes and 1,3-diiodobutadienes fused through an oxygen or nitrogen five-membered ring proceeded at ambient temperature to afford fully substituted polycyclic cyclo-octatetraenes in good yields. The fused ring moiety of the diiodides plays a critical role. The corresponding acyclic diiodide and a cyclohexane-fused analogue gave no coupling product, and a cyclopentane derivative showed only moderate reactivity. Correlation of the structures of the diiodides and their reactivity was established by an X-ray and density functional study.

Synthesis and Characterization of Polymer Brushes of Poly(N,N-dimethylacrylamide) from Polystyrene Latex by Aqueous Atom Transfer Radical Polymerization

Negatively charged polystyrene latex was synthesized, and a copolymer shell of 2-(methyl-2‘-chloropropionato)ethyl acrylate (HEA-Cl) and styrene was added, from which poly(N,N-dimethylacrylamide) (PDMA) was polymerized by atom transfer radical polymerization in aqueous suspension at room temperature. Increasing monomer concentration in the presence of CuCl or CuBr and one of three ligands (N,N,N‘,N‘,N‘ ‘-pentamethyldiethylenetriamine (PMDETA), 1,1,4,7,10,10-hexamethyltriethylenetetramine (HMTETA), and tris[2-(dimethylamino)ethyl]amine (Me6TREN)) produced grafts whose molecular weight increased to over 600 000 and polydispersities in the range of 1.3−1.8, determined from chains recovered following cleavage by base. Hydrodynamic brush thicknesses were 70−800 nm, and average chain separations, calculated from Mn and the mass of polymer recovered per particle, varied from 4.0 to 1.1 nm. Very high grafting densities were achieved with good molecular weight control, the highest densities yet reported for high m...

Selective preparation of pyridines, pyridones, and iminopyridines from two different alkynes via azazirconacycles.

Selective preparation of pyridine derivatives from two different alkynes and a nitrile was achieved by a novel procedure in which an alkyne and a nitrile couple first to give an azazirconacyclopentadiene followed by reaction with the second alkyne in the presence of 1 equiv of NiCl(2)(PPh(3))(2). This procedure gives only single products of pyridine derivatives from two different symmetrical alkynes and a nitrile. Our novel procedure can be used even with two similar alkyl-substituted alkynes such as 3-hexyne and 4-octyne. Two possible pyridine isomers from 3-hexyne, 4-octyne, and acetonitrile could be completely and independently prepared as single products by this method. The origin of the selectivity comes from the addition order of two different alkynes. This method was applied for the formation of pyridones and iminopyridines using isocyanate and carbodiimide derivatives instead of nitriles, respectively. Reaction of an alkyne with Cp(2)ZrEt(2) and an isocyanate or a carbodiimide gives an azazirconacycle. Treatment of the azazirconacycle with the second alkyne in the presence of 1 equiv of NiCl(2)(PPh(3))(2) gave a pyridone or an iminopyridine derivative. The use of two different unsymmetrical alkynes afforded the pyridine with five different substituents when the first alkyne has a trialkylsilyl group and the second alkyne has a phenyl group as functional groups. On the other hand, azazirconacyclopentadienes reacted with propargyl bromide in the presence of CuCl with excellent regioselectivity to give tetrasubstituted pyridine derivatives as single products. With the assistance of the trialkylsilyl groups, pyridines with all different substituents including H were also prepared.

Reactivity of the Carbyne Complexes [W2(μ-COR)(η5-C5H5)2(CO)2(μ-Ph2PCH2PPh2)]+(R = H, Me) toward Diazomethane

Reaction of [W2(μ-COH)Cp2(CO)2(μ-dppm)]BF4 (Cp = η5-C5H5; dppm = Ph2PCH2PPh2) with CH2N2 in the presence of CuCl at −75 °C leads to the methoxycarbyne cluster [CuW2Cl(μ3-COMe)Cp2(CO)2(μ-dppm)]BF4. Copper(I) chloride can be cleanly removed from the latter upon addition of PPh3, thus giving the methoxycarbyne complex [W2(μ-COMe)Cp2(CO)2(μ-dppm)]BF4. In the absence of CuCl, either the hydroxy or the methoxycarbyne ditungsten cations react with CH2N2 to give a mixture of the μ-methylene, μ-alkenyl compound [W2(μ-CH2){μ-η1:η2-C(OMe)CH2}Cp2(CO)2(μ-dppm)]BF4, which has been characterized through an X-ray study, and the μ-alkyne, μ-alkenyl species [W2{μ-η1:η2-C(OMe)CH}{μ-η1:η2-C(OMe)CH2}Cp2(CO)(μ-dppm)]BF4, the latter being the result of the addition of four molecules of CH2N2 to the starting hydroxycarbyne compound. The influence of experimental conditions on the above reactions has been analyzed through separate experiments. For example, the use of tetrahydrofuran as solvent almost suppresses the formation of t...

Microwave assisted Mannich reaction of terminal alkynes on alumina

Terminal alkynes, secondary amines, and formaldehyde undergo a Mannich reaction at room temperature in the presence of CuCl on Al2O3 without any organic solvent as reaction medium. The reaction can be promoted by microwave irradiation and is complete within one minute.

Copper(I)-catalyzed addition of trifluoromethylated benzyl radicals derived from aryltrifluoroethyl bromides to terminal olefins

Relatively unreactive aryltrifluoroethyl bromides were reacted with 1-octene in the presence of CuCl and 2,2′-bipyridyl at high temperatures. Trifluoromethylated benzyl radical was generated, and a diastereomer mixture of radical adducts was obtained with a (60–70):(40–30) diastereomer ratio. Ph3SnH reduction of the adducts gave the corresponding hydrocarbons with an isolated trifluoromethyl group. The reactions with styrene or aromatic and aliphatic silyl enol ethers led to the formation of trifluorodiphenylbutene and β-trifluoromethylated ketones, respectively.

Characterization of catalyst in the synthesis of dimethyl carbonate by gas-phase oxidative carbonylation of methanol

The bulk and surface properties of PdCl 2–CuCl 2–CH 3COOK catalysts supported on activated carbon (a.c.) used in the synthesis of dimethyl carbonate (DMC) by gas-phase oxidative carbonylation of methanol were characterized by XRD and XPS techniques. On the basis of the catalyst characterization and evaluation results, the active species of the catalyst has been suggested, and the reaction mechanism of oxidative carbonylation has been proposed. The interaction between CH 3COOK and PdCl 2 or CuCl 2 on the activated carbon support has been deduced from the formation of KCl, and the partial reduction of CuCl 2–CuCl has been found. Furthermore, the presence of CuCl 2 inhibits the reduction of PdCl 2. The experimental results show that the main reason for catalyst deactivation could be attributed to the loss of chlorine. Fortunately, promoter CH 3COOK could inhibit the loss of chlorine, and improve the electronic environment of PdCl 2–CuCl 2 catalyst, so that the stability and activity of the catalyst PdCl 2–CuCl 2–CH 3COOK/a.c. increase.

Arenediazonium Tetrachlorocuprates(II). Modified Versions of the Meerwein and Sandmeyer Reactions

Chloroarylation of unsaturated compounds with arenediazonium chlorides in the presence of CuCl2 as catalyst involves intermediate formation of arenediazonium tetrachlorocuprates(II) [ArN2 +]2 CuCl4 2-. A procedure for preparative isolation of these intermediates was developed, and they were shown to be efficient arylating agents. Reactions of [ArN2 +]2 CuCl4 2- with unsaturated compounds gave the corresponding Meerwein products; a mechanism was proposed for these reactions. In polar solvents arenediazonium tetra- chlorocuprates(II) are converted into chloroarenes, presumably through a cyclic transition state.

Study Concerning the Effects of Chelation on the Structure and Catalytic Activity of Ruthenium Carbene Complexes

The ruthenium chelate complexes 4 and 5 were prepared by reaction of the Grubbs catalyst 1 and its second-generation analogue 2 with the 2-vinylbenzoic acid isopropyl ester 3 in the presence of CuCl. The fact that the chelating carbonyl group in these complexes attenuates their catalytic activity sets an experimental basis for the interpretation of reactivity data previously described in the literature.

Palladium(II)‐catalyzed cyclization of W‐(2′,4′‐dienyl)‐2‐alkynamides to α‐alkylidene‐γ‐butyrolactams

AbstractIn the presence of CuCl2, N‐(2′, 4′‐dienyl)‐2‐alkynamides can be converted to α‐alkylidene‐σ‐butyrolactams under the catalysis of palladium(II). In this reaction, CuCl2 is used to oxidize Pd(0) to regenerate Pd(II), or the carbon‐palladium bond is quenched by the oxidative cleavage reaction of CuCl2.

Preparation of Polyisobutene-graft-Poly(methyl methacrylate) and Polyisobutene-graft-Polystyrene with Different Compositions and Side Chain Architectures through Atom Transfer Radical Polymerization (ATRP)

Polyisobutene-graft-poly(methyl methacrylate) and polyisobutene-graft-polystyrene with controlled compositions and side chain architectures were prepared through atom transfer radical polymerization (ATRP). Poly[isobutene-co-(p-methylstyrene)-co-(p-bromomethylstyrene)] (PIB) was used as a macroinitiator in the presence of CuCl or CuBr as a catalyst and dNbpy as a ligand. The compositions were controlled by the conversion of the monomer with polymerization time. The molecular weight distributions of the side chains were controlled through ATRP in the presence/absence of a halogen exchange reaction. DSC and DMA measurements showed that graft copolymers have two glass transition temperatures suggesting microphase separated behavior, which was also confirmed by SAXS measurements. The phase and dynamic mechanical behaviors were strongly affected by the compositions and/or the side chain architectures. The properties of the graft copolymers were controlled in a wide range leading to toughened glassy polymers or elastomers.