Copper Amine Complexes Research Articles

Synthesis of ultralong copper nanowires by reduction of copper-amine complexes

Ultralong copper nanowires with a mean diameter of 600nm and a length of 50µm were synthesized via the simple reduction of a copper–amine complex in an aqueous-nonpolar bilayer system. The use of a nonpolar solvent, such as cyclohexane, is important in this synthetic process. Several amines, including ethylenediamine (EDA), N,N-dimethylethylenediamine (DMEDA), N,N,N’,N’-tetramethylethylenediamine (TMEDA), and triethylenetetramine (TETA), were used to examine the ability of the different copper–amine complexes to form copper nanowires. Ultralong nanowires were obtained only in the case of the copper–TMEDA complex. Nanocubic Cu 2O was also observed on the surface of the nanowires; this oxide is formed by direct oxidation of copper in air.

Nanosized EDI-type molecular sieve

Nanosized EDI-type molecular sieve is prepared from aluminosilicate precursor solutions containing tetramethylammonium cations and copper amine complexes [Cu(NH 3) 4] 2+ as templates. The influence of chemical composition and various synthesis parameters on the size and degree of crystallinity of the EDI nanoparticles is investigated. The crystallization of nanosized EDI-type zeolite is shown to be directed by square planar [Cu(NH 3) 4] 2+ complexes used as co-templating species to the tetramethylammonium cations. The single addition of copper cations or ammonia leads to the crystallization of pure nanosized FAU zeolite, whereas the combination of both generates EDI-type microporous nanomaterial. Thus the [Cu(NH 3) 4] 2+ complexes offer new templating functions in addition to the classical quaternary ammonium additives for creation of nanosized molecular sieves.

Exceptionally Small Colloidal Zeolites Templated by Pd and Pt Amines

Monomodal colloidal suspensions containing EDI-type zeolite nanocrystals with sizes below 20 nm were prepared via a palladium and platinum amine templating approach. The role of the metal complexes in zeolite crystallization is elucidated using spectroscopic and microscopic characterization techniques in a series of samples containing pure Pd, Pt, and Cu amine complexes as well as mixtures of two compounds. The crystallization process of colloidal zeolites in precursor suspensions containing both [Pd(NH3)4]2+ and [Pt(NH3)4]2+ proceeds faster than in [Cu(NH3)4]2+ systems. The Pd and Pt complexes lead to a faster and enhanced nucleation rate in the precursor aluminosilicate suspensions in comparison to the copper amine complex. The latter explains both the smaller particle size and the higher monodispersity in the samples templated by Pd and Pt as compared to pure Cu-containing samples. Precursor systems containing mixed metal templates were used to control further the particle size and degree of metal loadings in the colloidal molecular sieves.

Morphology-controlled synthesis of Cu 2O microcrystal

Well-crystallized Cu 2O products were synthesized by reduction of a copper–amine complex solution with glucose under microwave irradiation. N, N, N′, N′-tetramethyl ethylenediamine (TMEDA) was used to form the copper–amine complex. Various morphologies such as hexapods, stars, octahedral, and cubes were obtained by varying the concentrations of glucose and the amine. The mechanisms for the formation of Cu 2O microcrystal of various morphologies were discussed.

The effect of polyoxometallate complexes of nickel and copper on the rate of their heterophase reaction with ammonia

It was established that the compounds formed by the cations in amine complexes of nickel(II) and copper(II) and the anions of polyoxometallates are capable of reacting stoichiometrically with gaseous ammonia when in the hydrated state. Some of the studied compounds are characterized by high sorption capacity (up to 40 molecules of adsorbate to a formula unit of the complex) and exhibit selectivity in the sorption of ammonia in the presence of water vapor.

Formation of High Nuclearity Mixed‐Valent Polyoxovanadates in the Presence of Copper Amine Complexes.

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Formation of high nuclearity mixed-valent polyoxovanadates in the presence of copper amine complexes

Two new Müller-type clusters, a one-dimensional solid [Cu(en)]2 4[Cl ⊂V15O36]−12H2O1, and a three-dimensional solid [Cu(pn)]2 4[Cl ⊂V18O42]·12H2O2, have been synthesised by employing identical hydrothermal conditions except varying the nature of organic diamine.1 crystallised in a chiral space groupP212121 witha = 12.757(1),b = 18.927(2) andc = 28.590(3) Å, andZ =4.2 crystallised in a tetragonal system with space groupP4/nnc,a = 15.113(1) andc = 18.542(3) Å, andZ = 2. Mixed-valent vanadium ions in structures1 and2 have been established both by magnetisation and bond-length bond-valence measurements. Chemistry of formation of high nuclearity polyoxovanadate clusters is discussed.

Activation of H 2O 2 by Amberlyst-15 resin supported with copper(II)-complexes towards oxidation of crystal violet

Copper(II) amine complexes supported on Amberlyst-15 cation resin were prepared and characterized by SEM, EDX and FTIR measurements. The kinetics of the heterogeneous oxidation of an organic dye, crystal violet, with H 2O 2 catalyzed by the supported catalysts was investigated in aqueous solution. The rate of reaction increases with increasing stability of the copper(II) amine complexes. The oxidation rate attained a first-order in the catalyst and the dye only at lower concentrations and second order in H 2O 2. A very fast formation of a peroxo-dye intermediate resulting from the interaction of H 2O 2 with the dye even in the presence of the catalyst was observed.

X-Ray Analysis of Methyl Cis-1-chloro-2-trichloromethylcyclopentane-1-carboxylate

Recently we have found that the products of 4,3-addition of trichloroacetic acid derivatives to 1,1-dichloro-4-methyl1,3-pentadiene in the presence of complex catalysts based on univalent copper undergo intramolecular cyclization, forming cyclobutanes with functional substituents [1, 2]. It was assumed that the stereoisomer composition of the isolated cyclobutanes depends on the ability of the functional group of the starting acid to be coordinated to the transition metal ion [3]. Further evidence in support of the observed tendencies was provided by cyclization of methyl 2,2,7,7-tetrachloro6-heptenate (prepared from methyl dichloroacetate and 1,1-dichloro-5-bromo-1-pentene by the procedure of [4], yield 72%) to 1-chloro-trichloromethylcyclopentane-1-carboxylic acid ester in the presence of amine complexes of univalent copper.

A combined ligand field and density functional theory study of the structural and spectroscopic properties of [Cu(dien)2]2+

Issues regarding assignment of the ‘d–d’ spectrum of [Cu(dien)2]Br2·H2O have been resolved using density functional theory (DFT) calculations. The fully optimised structure of [Cu(dien)2]2+ is in good agreement with experiment with Cu–N distances within ≈0.02–0.06 Å. However, one axial contact is 0.22 Å longer than reported and the ground state Cu–N covalency is overestimated. This leads to computed EPR g values which are too low and to ‘d–d’ transition energies which are too high. However, the electronic structure can be tuned to the experimental g values by modifying the copper nuclear charge. The ‘d–d’ transition energies were computed from the optimised electronic state using Slater’s transition state approach. DFT agrees with cellular ligand field (CLF) calculations and demonstrates that amines are not π-bonding ligands and that electrostatic interactions are not required for the CLF model. Instead, the observed spectroscopic and structural data are successfully reinterpreted as arising from the superposition of two, slightly different complexes in a ratio of approximately 5.5∶1 and aligned at about 90° to one another. This significantly improves the agreement between the calculated and ‘observed’ structures. The implications for the interpretation of the ‘d–d’ spectra of other copper(II) amine complexes are discussed.

ChemInform Abstract: Aerobic Oxidative Coupling of 2‐Naphthol Derivatives Catalyzed by a Copper—Amine Complex Without Solvent.

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New Stationary Phase Prepared by Immobilization of a Copper-Amine Complex on Silica and Its Use for High Performance Liquid Chromatography

Chromatographic silica (10 μm) was chemically modified with the silylating agent: [3-(2-aminoethyl)aminopropyl]trimethoxysilane (AEAPTS). The reaction product was characterized by elemental analysis and infrared and 13C and 29Si NMR spectra. The chemically modified silica was treated with Cu(II) in methanol medium. This cation was strongly adsorbed through complexation by the pendant ethylenediamine groups attached to the silica surface. The complex formed on the silica surface was shown to be stable in both aqueous and non-aqueous media. The aim of Cu(II) immobilization is to use this new material as a stationary phase in High Performance Liquid Chromatography (HPLC). Separations of synthetic mixtures of aromatic amines and of polyaromatic hydrocarbons were undertaken using 150×3.9 mm HPLC columns packed with the modified silica, with and without copper ions, to follow the influence of the cation on the chromatographic separation and to verify the efficiency of the new stationary phase for HPLC.

Aerobic Oxidative Coupling of 2-Naphthol Derivatives Catalyzed by a Copper-Amine Complex without Solvent.

Aerobic oxidative coupling of naphthols catalyzed by a copper-amine complex was found to proceed without solvent in high efficacy. The present reaction was applied to a practical synthesis of 1, 1'-binaphthalene-2, 2'-diol on multi-gram scale.

Catalyst Effects on the Stereoselectivity of Addition of Tetrachloromethane to 1,3-Cyclohexadiene

The stereoselectivity of addition reaction of tetrachloromethane with conjugate cyclodienes represented by 1,3-cyclohexadiene has been studied in respect to the type of catalyst. In all addition reactions the product of 1,4-addition, i.e. 1-chloro-4-(trichloromethyl)cyclohex-2-ene was formed exclusively consisting of two isomers (1a, 1d). Copper-amine complexes gave higher isomeric ratio 1a : 1d (up to 3.7) than ruthenium complex (1.3) at the same conditions (80 °C). Moreover, it was found that isomeric ratio was temperature dependent and the highest value (6.4) was obtained at lower temperature (20 °C). The results proved both catalyst and ligand effects on stereoselectivity of addition reaction of conjugated cyclic dienes. This supports a non-chain reaction mechanism because isomeric ratios of chain reactions are catalyst independent.

Interpretation of Electronic and EPR Spectra of Copper(II) Amine Complexes: A Test of the MM-AOM Method

The strain energy minimized structures (MM) of a series of copper(II) tetraamines ([Cu((R)-ahaz)((S)-ahaz)]2+, (R)-ahaz (1) = (R)-3-aminohexahydroazepine, (S)-ahaz (2) = (S)-3-aminohexahydroazepine; [Cu((S)-ahaz)2-(OH2)]2+; [Cu(mn[13]aneN4)(OH2)2]2+, mn[13]aneN4 (3) = 12-methyl-12-nitro-1,4,7,10-tetraazacyclotridecane; [Cu(mn[13]aneN4)(OH2)]2+; [Cu(mn[14]aneN4)(OH2)]2+, mn[14]aneN4 (4) = 6-methyl-6-nitro-1,4,8,11-tetraazacyclotetradecane; [Cu(mn[15]aneN4)(OH2)]2+, mn[15]aneN4 (5) = 10-methyl-10-nitro-1,4,8,12-tetraazacyclopentadecane; [Cu(mn[15]aneN4)(OH2)2]2+; [Cu(mn[16]aneN4)(OH2)]+, mn[16]ane N4 (6) = 3-methyl-3-nitro-1,5,9,13-tetraazacyclohexadecane; [Cu(en)2(OH2)2]2+, en (7) = ethane-1,2-diamine), with square planar, square pyramidal, and distorted octahedral chromophores exhibiting various degrees of tetrahedral distortion of the central coordination plane, are in good agreement with published X-ray structures (where available) and the two crystal structures reported in this paper. [Cu(2)2(ClO)4](ClO4) crystallizes in the orthorhombic space group P212121, with a = 7.815(5) A, b = 14.350(2) A, c = 18.194(4) A, Z = 4, and Rw = 0.061. [Cu(5)(Cl)2]·2H2O crystallizes in the triclinic space group P1, with a = 6.884(2) A, b = 9.090(3) A, c = 9.214(2) A, α = 105.13(2)°, β = 107.40(2)°, γ = 107.85(2)°, Z = 1, and Rw = 0.022. The spin Hamiltonian parameters and electronic transitions, estimated with the angular overlap model (AOM) based on the strain energy minimized structures of the chromophores, where generally water is used as axial ligand (MM-AOM), are in reasonable agreement with the calculated spectroscopic parameters based on experimental structures (AOM) and with the experimental spectroscopic data (UV-vis-near-IR and EPR spectra of single crystals, powders, glasses, and solutions). The calculated spectroscopic data are based on a constant set of electronic parameters which depend on the degree of substitution of the amine, on the Cu-N bond length, and on the degree of misdirected valences. © 1995 American Chemical Society.

Copper-amine speciation: an electrochemical investigation of the selection of volatile amines for steam generator water

Addition of volatile amines for pH control to steam generator water of power plants to protect the steam water system for corrosion is called all volatile treatment (AVT) of steam generator water. Metal ion concentrations in steam generator water will generally be in the μg 1 −1 range. Pseudopolarography in combination with differential pulse anodic stripping voltammetry copper speciation studies (at 50 μg 1 −1 copper concentration) were carried out in aqueous media containing four important amines, viz. 3-methoxypropylamine (3MPA), 1-dimethylamino-2-propanol (DMPA), 2-dimethylaminoethanol (DMAE) and piperidine (Pip), all having a large potential for use as AVT reagents. The copper-amine complexes were identified and their log stability constants (log K) values were as follows: [Cu(I)(3MPA) 2]: 10.47; [Cu(II)(OH) 2(DMPA) 2]: 20.33; [Cu(II)(OH) 2(DMAE) 2]: 20.51; [Cu(I)(Pip)]: 8.29; [Cu(I)(Pip) 2]: 9.89; [Cu(I)(OH) 2(Pip) 2]: 16.67. Electroreduction mechanisms of these identified species at a hanging mercury drop electrode were studied. The ability of some of the amines to influence the stepwise reduction/oxidation of copper results in impeding its transport in dissolved form in the steam generator water. Hence it is recommended that only those amines that do not stabilize Cu(I) in solution be selected for use as AVT reagents for ensuring better performance of steam water circuits in power industries.

Reactivity of mono- and di-methoxycarbonyl complexes of Pd II towards amines and copper amine complexes: role of copper in the catalyzed palladium-copper oxidative carbonylation of amines

The reactivity of mono- and di-methoxycarbonyl complexes of palladium of formula [PdL 2Cl 2- n (COOCH 3) n ] ( n = 1 or 2; L 2 = chelating ligand) towards amines in the presence of [RNH 3]Cl or CuCl 2 has been studied. The reactions yield N, N′-disubstituted ureas or carbamates, respectively. These results are compared with the dioxygen-induced carbonylative oxidation of amines catalyzed by palladium-based systems.

Addition of diethyl trichloromethylphosphonate to olefins catalysed by copper complexes

Diethyl trichloromethyl phosphonate is added on olefins by non-chain catalytic reactions catalysed by copper amine complexes.

Polymerization of 2,6-Dimethylphenol with Mixed-Ligand Copper Complexes

Oxidative polymerization of 2,6-dimethylphenol to poly(2,6-dimethyl-1,4-phenylene ether) (PPE) was catalyzed by copper-amine complexes which were prepared from cuprous oxide, hydrobromic acid, and amines. An unexpected synergistic phenomenon was observed for the mixed n-butylamine dibutylamine-copper complex. Under identical reaction conditions, the polymer produced with the mixed-amine copper complex had much higher molecular weight than those produced with the single-amine copper complexes. The best n-butylamine/dibutylamine composition for the mixed-amine copper complex was found to be at 1:1 molar ratio, which gave the highest intrinsic viscosity and the highest PPE yield with little change in 3,3',5,5'-tetramethyldiphenoquinone yield and nitrogen content

Effect of mineral nutrients on the kinetics of methane utilization by methanotrophs

The effect of different mineral nutrients on the kinetics of methane biodegradation by a mixed culture of methanotrophic bacteria was studied. The substrate factors examined were ammonia, iron, copper, manganese, phosphate, and sulphide. The presence of iron in the growth medium had a strong effect on the yield coefficient. Yield coefficients up to 0.49 mg protein per mg methane were observed when iron was added at concentrations of 0.10–5.0 mg/l. Iron addition also increased the maximum methane utilization rate. The same effect was observed after addition of ammonium to a medium where nitrate was the only nitrogen source. The observed Monod constant for methane utilization increased with increasing concentration of ammonia. This shows that ammonia is a weak competitive inhibitor as observed by other researchers. Relatively high levels of both ammonia (70 mg/l) and copper (300 µg/l) inhibited the methane degradation, probably due to the toxic effect of copper-amine complexes.