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Of Cu

NH4][ON(NO)C6Hj]. a reagent originally suggested for use in the detection of Cu but now used for the separation of Fe/Ti and Zr which it precipitates from acid solutions. Cupferron is a brownish-while crystalline substance, soluble in water. [Pg.118]

Electron Spin Resonance Spectroscopy. Several ESR studies have been reported for adsorption systems [85-90]. ESR signals are strong enough to allow the detection of quite small amounts of unpaired electrons, and the shape of the signal can, in the case of adsorbed transition metal ions, give an indication of the geometry of the adsorption site. Ref. 91 provides a contemporary example of the use of ESR and of electron spin echo modulation (ESEM) to locate the environment of Cu(II) relative to in a microporous aluminophosphate molecular sieve. [Pg.586]

Jensen F, Besenbacher F, Laesgaard E and Stensgaard I 1990 Surface reconstruction of Cu (110) induced by oxygen chemisorption Phys. Rev. B 41 10 233... [Pg.317]

Figure A2.5.22. The experimental heat eapaeity of a p-brass (CiiZn) alloy eontaining 48.9 atomie pereent Zn as measured by Moser (1934). The dashed line is ealeulated from the speeifie heats of Cu and Zn assuming an ideal mixture. Reprodueed from [6] Nix F C and Shoekley W 1938 Rev. Mod. Phy.s. 10 4, figure 4. Copyright (1938) by the Arneriean Physieal Soeiety. Figure A2.5.22. The experimental heat eapaeity of a p-brass (CiiZn) alloy eontaining 48.9 atomie pereent Zn as measured by Moser (1934). The dashed line is ealeulated from the speeifie heats of Cu and Zn assuming an ideal mixture. Reprodueed from [6] Nix F C and Shoekley W 1938 Rev. Mod. Phy.s. 10 4, figure 4. Copyright (1938) by the Arneriean Physieal Soeiety.
Niehus H, Spitzl R, Besocke Kand Comsa G 1991 N-induced (2 x 3) reconstruction of Cu(110) evidence for long-range, highly directional interaction between Cu-N-Cu bonds Phys. Rev. B 43 12 619-25... [Pg.1825]

Zuo J, Pandey R and Kunz A B 1992 Embedded-oluster study of Cu -lnduoed lattloe relaxation In alkali halides Phys. Rev. B 45 2709-11... [Pg.2234]

The random-bond heteropolymer is described by a Hamiltonian similar to (C2.5.A3) except that the short-range two-body tenn v.j is taken to be random with a Gaussian distribution. In this case a tliree-body tenn with a positive value of cu is needed to describe the collapsed phase. The Hamiltonian is... [Pg.2663]

Figure C2.10.2. Cyclic voltammogram of Cu(l 11)/10 mM HCl and in situ measured STM micrographs revealing tire bare Cu(l 1 l)surface (-1.05 V, left) and tire (V3 x A/3)R30°-Cladsorbate superstmcture (-0.6 V, right) (from [39]). Figure C2.10.2. Cyclic voltammogram of Cu(l 11)/10 mM HCl and in situ measured STM micrographs revealing tire bare Cu(l 1 l)surface (-1.05 V, left) and tire (V3 x A/3)R30°-Cladsorbate superstmcture (-0.6 V, right) (from [39]).
At potentials positive to the bulk metal deposition, a metal monolayer-or in some cases a bilayer-of one metal can be electrodeposited on another metal surface this phenomenon is referred to as underiDotential deposition (upd) in the literature. Many investigations of several different metal adsorbate/substrate systems have been published to date. In general, two different classes of surface stmetures can be classified (a) simple superstmetures with small packing densities and (b) close-packed (bulklike) or even compressed stmetures, which are observed for deposition of the heavy metal ions Tl, Hg and Pb on Ag, Au, Cu or Pt (see, e.g., [63, 64, 65, 66, 62, 68, 69 and 70]). In case (a), the metal adsorbate is very often stabilized by coadsorbed anions typical representatives of this type are Cu/Au (111) (e.g. [44, 45, 21, 22 and 25]) or Cu/Pt(l 11) (e.g. [46, 74, 75, and 26 ]) It has to be mentioned that the two dimensional ordering of the Cu adatoms is significantly affected by the presence of coadsorbed anions, for example, for the upd of Cu on Au(l 11), the onset of underiDotential deposition shifts to more positive potentials from 80"to Br and CE [72]. [Pg.2753]

Figure C2.10.5. Magnitude of the Fourier transfonn of tire /c-weighted absorjDtion fine stmcture k (/c) measured at tire Cu K edge for tire underiDotential deposition of Cu/Au(l 11) from 0.1 M KCIO +IO M HCIO +S x 10 M Cu (010 )2+10 M potassium salt of sulfate, chloride, bromide and a mixture of sulfate and chloride, for polarization of tire x-rays parallel to tire sample surface ( ) or parallel to tire surface nonnal (E (from [81]). Figure C2.10.5. Magnitude of the Fourier transfonn of tire /c-weighted absorjDtion fine stmcture k (/c) measured at tire Cu K edge for tire underiDotential deposition of Cu/Au(l 11) from 0.1 M KCIO +IO M HCIO +S x 10 M Cu (010 )2+10 M potassium salt of sulfate, chloride, bromide and a mixture of sulfate and chloride, for polarization of tire x-rays parallel to tire sample surface ( ) or parallel to tire surface nonnal (E (from [81]).
Magnussen O M, Hotios J, Nichois R J, Koib D M and Behm R J 1990 Atomic structure of Cu adiayers on Au(IOO) and Au(111) eiectrodes observed by in situ scanning tunneiing microscopy Phys. Rev. Lett. 64 2929-32... [Pg.2757]

In the presence of appropriate ligands, the values may be affected sufficiently to make Cu(l) stable but since the likely aquo-complex which Cu(I) would form is [Cu(H20)2], with only two water ligands, the (hypothetical) hydration energy of Cu is therefore much less than that of the higher charged, more strongly aquated [Cu(H20)e]. ... [Pg.414]

Klapper, I., Hagstrom, R., Fine, R., Sharp, K., Honig, B. Focusing of electric fields in the active site of cu,zn superoxide dismutase. Proteins Struct. Pune. Genet. 1 (1986) 47-79. [Pg.195]

The rate of the uncatalysed reaction in all four solvents is rather slow. (The half-life at [2.5] = 1.00 mM is at least 28 hours). However, upon complexation of Cu ion to 2.4a-g the rate of the Diels-Alder reaction between these compounds and 2.5 increases dramatically. Figure 2.2 shows the apparent rate of the Diels-Alder reaction of 2.4a with 2.5 in water as a lunction of the concentration of copper(II)nitrate. At higher catalyst concentrations the rate of the reaction clearly levels off, most likely due to complete binding of the dienophile to the catalyst. Note that in the kinetic experiments... [Pg.53]

Figure 3.4. TJV-vis absorption spectra of 3.10c in water and in water containing 3.0 mM of Cu (glycine) complex, 3.0 mM of Cu(N-methyl-Ftyrosine) and 3.0 mM of Cu(L-abrine). Figure 3.4. TJV-vis absorption spectra of 3.10c in water and in water containing 3.0 mM of Cu (glycine) complex, 3.0 mM of Cu(N-methyl-Ftyrosine) and 3.0 mM of Cu(L-abrine).
In a typical experiment 105 mg (0.50 mmol) of 3.8c, dissolved in a minimal amount of ethanol, and 100 mg (1.50 mmol) of 3.9 were added to a solution of 1.21g (5 mmol) of Cu(N03)2 BH20 and 5 mmol of ligand in 500 ml of water in a 500 ml flask. -Amino-acid containing solutions required addition of one equivalent of sodium hydroxide. When necessary, the pH was adjusted to a value of 5 ( -amino acids) and 7.5 (amines). The flask was sealed carefully and the solution was stirred for 2A hours, followed by extraction with ether. After drying over sodium sulfate the ether was evaporated. Tire endo-exo ratios were determined from the H-NMR spectra of the product mixtures as described in Chapter 2. [Pg.103]

In a typical procedure, a solution of 0.175 mmol of L- -amino acid and 0.175 mmol of NaOH in 1 ml of water was added to a solution of 0.100 mmol of Cu(N03)2in 100 ml of water in a 100 ml flask. Tire pH was adjusted to 6.0-6.5. The catalyst solution was cooled to 0 C and a solution of 1.0 mmol of 3.8c in a minimal amount of ethanol was added, together with 2.4 mmol of 3.9. The flask was sealed carefully. After 48 hours of stirring at 0 C the reaction mixture was extracted with ether, affording 3.10c in quantitative yield After evaporation of the ether from the water layer (rotary evaporator) the catalyst solution can be reused without a significant decrease in enantioselectivity. [Pg.103]

It turned out that the dodecylsulfate surfactants Co(DS)i Ni(DS)2, Cu(DS)2 and Zn(DS)2 containing catalytically active counterions are extremely potent catalysts for the Diels-Alder reaction between 5.1 and 5.2 (see Scheme 5.1). The physical properties of these micelles have been described in the literature and a small number of catalytic studies have been reported. The influence of Cu(DS)2 micelles on the kinetics of quenching of a photoexcited species has been investigated. Interestingly, Kobayashi recently employed surfactants in scandium triflate catalysed aldol reactions". Robinson et al. have demonshuted that the interaction between metal ions and ligand at the surface of dodecylsulfate micelles can be extremely efficient. ... [Pg.139]

Table 5.5. Influence of micelles of Cu(DS)2, CTAB and C12E7 on the apparent second-order rate constants (M s" ) for the copper(II) catalysed Diels-Alder reaction of 5.1c, 5.If and 5.1 g with 5.2 at 25 C . Table 5.5. Influence of micelles of Cu(DS)2, CTAB and C12E7 on the apparent second-order rate constants (M s" ) for the copper(II) catalysed Diels-Alder reaction of 5.1c, 5.If and 5.1 g with 5.2 at 25 C .
Figure 5.6. Plots of the apparent second-order rate constant (kap-p) versus the concentration of Cu(DS )2 for the Diels-Alder reaction of S.lc ( ), 5.1 f (f ) and 5.1 g (jsC) with 5.2 at 25 C. The inset shows the treatment of the data for the reaction of 5.1g according to the pseudophase model. Figure 5.6. Plots of the apparent second-order rate constant (kap-p) versus the concentration of Cu(DS )2 for the Diels-Alder reaction of S.lc ( ), 5.1 f (f ) and 5.1 g (jsC) with 5.2 at 25 C. The inset shows the treatment of the data for the reaction of 5.1g according to the pseudophase model.
Fonnation of a complex with a copper cation only further stimulates this behaviour. As a result, S.lg is almost completely bound to the micelles, even at low concentrations of Cu(DS)2. By contrast, the reaction of 5.1 f still benefits from an increasing surfactant concentration at 10 mM of Cu(DS)2. In fact, it is surprising that the reaction of this anionic compound is catalysed at all by an anionic surfactant. Probably it is the copper complex of 5.If, being overall cationic, that binds to the micelle. Not surprisingly, the neutral substrate S.lc shows intermediate behaviour. [Pg.143]

Interestingly, at very low concentrations of micellised Qi(DS)2, the rate of the reaction of 5.1a with 5.2 was observed to be zero-order in 5.1 a and only depending on the concentration of Cu(DS)2 and 5.2. This is akin to the turn-over and saturation kinetics exhibited by enzymes. The acceleration relative to the reaction in organic media in the absence of catalyst, also approaches enzyme-like magnitudes compared to the process in acetonitrile (Chapter 2), Cu(DS)2 micelles accelerate the Diels-Alder reaction between 5.1a and 5.2 by a factor of 1.8710 . This extremely high catalytic efficiency shows how a combination of a beneficial aqueous solvent effect, Lewis-acid catalysis and micellar catalysis can lead to tremendous accelerations. [Pg.143]

Calculations usirig this value afford a partition coefficient for 5.2 of 96 and a micellar second-order rate constant of 0.21 M" s" . This partition coefficient is higher than the corresponding values for SDS micelles and CTAB micelles given in Table 5.2. This trend is in agreement with literature data, that indicate that Cu(DS)2 micelles are able to solubilize 1.5 times as much benzene as SDS micelles . Most likely this enhanced solubilisation is a result of the higher counterion binding of Cu(DS)2... [Pg.144]

Figure 5.8. Paramagnetic ion-induced spin-lattice relaxation rates (rp) of the protons of 5.1c and 5.1 f in CTAB solution and of CTAB in the presence of 5.1c or 5.1 f, normalised to rpfor the surfactant -CH-j. The solutions contained 50 mM of CTAB, 8 mM of 5.1c or 5.1f and 0 or 0.4 mM of [Cu (EDTA) f ... Figure 5.8. Paramagnetic ion-induced spin-lattice relaxation rates (rp) of the protons of 5.1c and 5.1 f in CTAB solution and of CTAB in the presence of 5.1c or 5.1 f, normalised to rpfor the surfactant -CH-j. The solutions contained 50 mM of CTAB, 8 mM of 5.1c or 5.1f and 0 or 0.4 mM of [Cu (EDTA) f ...
In contrast to the situation in the absence of catalytically active Lewis acids, micelles of Cu(DS)2 induce rate enhancements up to a factor 1.8710 compared to the uncatalysed reaction in acetonitrile. These enzyme-like accelerations result from a very efficient complexation of the dienophile to the catalytically active copper ions, both species being concentrated at the micellar surface. Moreover, the higher affinity of 5.2 for Cu(DS)2 compared to SDS and CTAB (Psj = 96 versus 61 and 68, respectively) will diminish the inhibitory effect due to spatial separation of 5.1 and 5.2 as observed for SDS and CTAB. [Pg.154]


See other pages where Of Cu is mentioned: [Pg.202]    [Pg.278]    [Pg.304]    [Pg.360]    [Pg.175]    [Pg.318]    [Pg.1772]    [Pg.1774]    [Pg.1963]    [Pg.2749]    [Pg.2754]    [Pg.2754]    [Pg.2759]    [Pg.2759]    [Pg.59]    [Pg.165]    [Pg.165]    [Pg.121]    [Pg.142]    [Pg.144]    [Pg.151]    [Pg.152]    [Pg.153]    [Pg.176]    [Pg.177]    [Pg.173]   
See also in sourсe #XX -- [ Pg.2 , Pg.3 , Pg.6 , Pg.16 , Pg.22 , Pg.262 , Pg.271 ]




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Activation of Cu

Adhesion Force of Silica and Alumina on Cu

Adsorption of CO on Cu Electrode Voltammetric and Spectroscopic Studies

Adsorption of Cu ions

Application of Cu Catalysts

Applications of the Cu-Catalyzed Azide-Alkyne Cycloaddition (CuAAC) in Peptides

Complexes of group 11 (Cu, Ag, Au)

Conductivity of Cu

Cyclopropanation, Epoxidation, and Aziridination of Alkenes (Cu, Rh, Mn, Ti)

D Electro-Deposits of Cu-Sn Alloy

Deposition of Cu Interconnections on Chips

Diffusivity of Cu

Disproportionation of Cu

Effect of Cu addition

Electrochemical Polarization Study of Corrosion Inhibitors in Cu CMP Slurry

Electronic properties of Cu

Enones effect of Cu on reaction with Grignard

Enthalpy of Cu

Equilibrium in Transitions of the Cu-Zn Type

Evaporation of Cu

Fabrication Process of CdS-Cu S Cells

Formation of Nonnative Cu-BTA Surface Film

HIGH STRAIN RATE SUPERPLASTIC BEHAVIOR OF Al-Li-Mg-Cu-Sc ALLOY SUBJECTED TO SEVERE PLASTIC DEFORMATION

Importance of the apical Cu-O distance, Madelung potentials and bond valence sums

Inhibition of Cu

Investigation on the Superior Hydrothermal Stability of Small-Pore Zeolite Supported Cu SCR Catalyst

Isotope Study of the Silver Bell Porphyry Cu Mine

Kinetic Modeling of Ammonia SCR for Cu-Zeolite Catalysts

Mass spectrum of Cu/Zn superoxide dismutase

New Developments Pharmaceutical Applications of Cu-Catalyzed Aerobic Oxidation Reactions

Oxidation of [Cu

Pattern Effects on Planarization Efficiency of Cu Electropolishing

Petrographic characterization of propylitic alteration associated with porphyry Cu-Mo deposits in the Collahuasi District. Northern Chile implications for mineral exploration

Preparation of (Cu(en)

Preparation of Pd-Cu alloy composite membranes

Prostaglandin effect of Cu complexes on biosynthesis

Rate of Cu

Reduction of Cu

Removal of Cu

Replacement of Cu with

Results of Model Calculations for the Cu-Ni System

Separation of the Cu-group (Solution I)

Sites of Cu

Solubility of Cu

Spectrum of Cus

Step of Substrate to Polymer-Cu Catalysts

Surface Effects of the Cu S Film

Surface Treatment, Alloying and Modification of Cu Electrode

Synthesis of metal nanoparticles (Au, Ag, Pt, Cu) on semiconductor surface by photostimulated deposition from solution

Technology of CdS-Cu S Photovoltaic Generators

Template-Assisted Electrochemical Growth of Cu Nanorods and Nanowires

The Electrolytic Production of Al-Cu-Li Master Alloy by Molten Salts Electrolysis

The electronic structure of N on Cu

Till indicator mineral and geochemical signatures of magmatic Ni-Cu deposits, Thompson Nickel Belt, central Canada

Tip Contacts of Various Metals to Cu(TCNQ)

Titrimetric Determination of Cu Solution

Transitions of the Cu-Zn Type with Arbitrary Composition

X-ray crystal structure of Cu

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