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Copper atom

The other phthalocyanines are derived from the above by replacement of the copper atom by two atoms of a monopositive or by one atom of a dipositive metal. [Pg.313]

Given that the concentration of both the copper atoms and the electrons m the copper metal will be effectively constant, so that two of the activity tenns can be neglected, we finally have, on rearranging A2.4.107,... [Pg.598]

Figure C3.1.10. (a) Steady state IR difference spectmm (dark minus light) of cytoclirome c oxidase CO complex measured at low temperature (127 K). This protein contains a copper atom situated immediately adjacent to a haem... Figure C3.1.10. (a) Steady state IR difference spectmm (dark minus light) of cytoclirome c oxidase CO complex measured at low temperature (127 K). This protein contains a copper atom situated immediately adjacent to a haem...
A key step in the reaction mechanism appears to be nucleophilic attack on the alkyl halide by the negatively charged copper atom but the details of the mechanism are not well understood Indeed there is probably more than one mechanism by which cuprates react with organic halogen compounds Vinyl halides and aryl halides are known to be very unreactive toward nucleophilic attack yet react with lithium dialkylcuprates... [Pg.604]

These reagents contain a negatively charged copper atom and are formed by the reaction of a copper(l) salt with two equivalents of an organolithium reagent... [Pg.615]

Why is this relevant to the diffusion of zinc in copper Imagine two adjacent lattice planes in the brass with two slightly different zinc concentrations, as shown in exaggerated form in Fig. 18.5. Let us denote these two planes as A and B. Now for a zinc atom to diffuse from A to B, down the concentration gradient, it has to squeeze between the copper atoms (a simplified statement - but we shall elaborate on it in a moment). This is another way of saying the zinc atom has to overcome an energy barrier... [Pg.181]

The second mechanism is that of vacancy diffusion. When zinc diffuses in brass, for example, the zinc atom (comparable in size to the copper atom) cannot fit into the interstices - the zinc atom has to wait until a vacancy, or missing atom, appears next to it before it can move. This is the mechanism by which most diffusion in crystals takes place (Figs. 18.7 and 10.4). [Pg.185]

The alloy aluminium-4 wt% copper forms the basis of the 2000 series (Duralumin, or Dural for short). It melts at about 650°C. At 500°C, solid A1 dissolves as much as 4 wt% of Cu completely. At 20°C its equilibrium solubility is only 0.1 wt% Cu. If the material is slowly cooled from 500°C to 20°C, 4 wt% - 0.1 wt% = 3.9 wt% copper separates out from the aluminium as large lumps of a new phase not pure copper, but of the compound CuAlj. If, instead, the material is quenched (cooled very rapidly, often by dropping it into cold water) from 500°C to 20°C, there is not time for the dissolved copper atoms to move together, by diffusion, to form CuAlj, and the alloy remains a solid solution. [Pg.324]

In some materials, semiconductors in particular, interstitial atoms play a crucial role in diffusion. Thus, Frank and Turnbull (1956) proposed that copper atoms dissolved in germanium are present both substitutionally (together with vacancies) and interstitially, and that the vacancies and interstitial copper atoms diffuse independently. Such diffusion can be very rapid, and this was exploited in preparing the famous micrograph of Figure 3.14 in the preceding chapter. Similarly, it is now recognised that transition metal atoms dissolved in silicon diffuse by a very fast, predominantly interstitial, mechanism (Weber 1988). [Pg.169]

Cytochrome c oxidase contains two heme centers (cytochromes a and %) as well as two copper atoms (Figure 21.17). The copper sites, Cu and Cug, are associated with cytochromes a and respectively. The copper sites participate in electron transfer by cycling between the reduced (cuprous) Cu state and the oxidized (cupric) Cu state. (Remember, the cytochromes and copper sites are one-electron transfer agents.) Reduction of one oxygen molecule requires passage of four electrons through these carriers—one at a time (Figure... [Pg.690]

Cytochrome c oxidase contains two, or possibly three, copper atoms referred to as Cua and Cub since they do not fit into the usual classification. The former (possibly a dimer) is situated outside the mitochondrial membrane, whereas the latter is associated with an iron atom within the membrane. Both have electron transfer functions but details are as yet unclear. [Pg.1199]

The absolute configuration of the cycloaddition product obtained by the reaction of ketones with activated dienes catalyzed by (S)-t-Bu-BOX-Cu(II) (S)-21b points also to an intermediate in which the geometry around the central copper atom is square-planar similar to 26 above, and that the diene approaches the carbonyl functionality in an endo fashion. [Pg.175]

Eacli of tlie four organic moieties bridges between an equatorial and an axial copper atom tlirougli its C( 1) atom, while tlie nitrogen atom in tlie substituent is coordinated to an adjacent equatorial copper atom. Hie two bromine atoms bridge, at opposite sites, between two equatorial copper atoms. Tliis structural ariange-menl has tlie consequence tliat tlie aggregate incorporates two distinct types of... [Pg.17]


See other pages where Copper atom is mentioned: [Pg.598]    [Pg.1774]    [Pg.644]    [Pg.422]    [Pg.504]    [Pg.109]    [Pg.395]    [Pg.395]    [Pg.645]    [Pg.176]    [Pg.105]    [Pg.26]    [Pg.722]    [Pg.1190]    [Pg.1192]    [Pg.1192]    [Pg.2]    [Pg.3]    [Pg.5]    [Pg.7]    [Pg.10]    [Pg.10]    [Pg.11]    [Pg.11]    [Pg.12]    [Pg.14]    [Pg.14]    [Pg.14]    [Pg.17]    [Pg.17]    [Pg.18]    [Pg.19]    [Pg.20]    [Pg.20]    [Pg.22]    [Pg.23]   
See also in sourсe #XX -- [ Pg.18 ]

See also in sourсe #XX -- [ Pg.85 ]




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Atom transfer radical addition copper-catalyzed

Atom transfer radical additions copper

Atom transfer radical cyclization copper complexes

Atom transfer radical polymerization active copper complexes

Atomic structure copper

Boron atomic copper

Control of Tautomerization with Single Copper Atoms

Copper and oxygen atoms

Copper atom clustering

Copper atom configurations

Copper atomic absorption

Copper atomic absorption spectrometry

Copper atomic core

Copper atomic energy levels

Copper atomic hydrogen

Copper atomic mass

Copper atomic properties

Copper atomic spectrum

Copper atomic weight

Copper atoms Jahn-Teller effect

Copper atoms, reaction + halogens

Copper catalyst atoms

Copper catalysts atom/group-transfer reactions

Copper catalyzed reactions addition Atom

Copper metal atoms

Electrothermal atomization copper

Halides atomic copper

Quantum mechanics copper atom

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