Copper bonding

The resistivity of the soil in any particular location will be a function of moisture content, soil temperature and presence of dissolved salts. At a site where climatic conditions vary considerably throughout the year, earth electrodes should be buried at a depth where such changes will not affect the resistivity. Grounding rods are generally made of copper bonded onto a steel core. The copper provides a good connection to earth and offers a high corrosion resistance, while the steel core gives the mechanical... 

Fig. 1.4. Molecular orbitals describing the bridging aryl copper bonding (see text).

This type of copper cluster has not previously been observed in any metalloprotein. Despite the fact that the structure of this important crystal has been solved, much remains for scientists to learn about the physical, spectroscopic, and chemical properties of the Cuz catalytic center. For example, we could ask ourselves questions such as these First of all, are there copper-copper bonds present in the cluster Second, why are four copper ions needed for a two-electron reduction (78 words aim for 62 words)... 

K, the static disorder is certainly maintained. The results are presented as plots of formula in Fig. 7. The deviations from linearity of the plots is small enough to support such method of analysis. The slopes of the curves give the 5a values tabulated in Table 4. It follows that in the (1 x l)Co/Cu(lll) case the anisotropy of surface vibrations clearly appears in the measured values of 8a and 5aT There are two reasons for such anisotropy the first is a surface effect due to the reduced coordination in the perpendicular direction. cF is a mean-square relative displacement projected along the direction of the bond Enhanced perpendicular vibrational amplitude causes enhanced mean-square relative displacement along the S—B direction. The second effect is due to the chemical difference of the substrate (Fig. 8). S—B bonds are Co—Cu bonds and the bulk Co mean-square relative displacement, cr (Co), is smaller than the bulk value for Cu, aJ(Cu). Thus for individual cobalt-copper bonds, the following ordering is expected ... 

Recently, a unique double difluoromethylene insertion into the carbon-copper bond of pentafluorophenylcopper has been reported [239]. Pentafluoro-phenylcopper reacted with trifluoromethylcopper in DMF at -30 °C to room temperature to form perfluoro-2-phenylethylcopper (C6F5CF2CF2Cu) in high yield, which readily underwent a variety of functionalization reactions with electrophiles [239] (Scheme 79). 

The reaction is believed to proceed via a c-allyl copper complex, in which the carbon-copper bond is formed at the "/-position, anti to the acetate leaving group. Reductive elimination of copper led to pure "/-substitution. With cyclic aliphatic allylic acetates, the selectivity is generally lower because the o-allyl copper complex can isomerize to the ir-allyl complex with loss of regioselectivity. 

A compound containing carbon-copper bonds, commonly of formula R2CuLi (Gilman reagent). The lithium dialkylcuprate (or diarylcuprate or divinylcuprate) displaces an organohalogen bond to form a new C—C. (p. 791)... 

Strong o-donor and rc-acceptor stable Of-copper bond in oxyhemocyanin... 

Isocyanide complexes of phenylethynyl-, indenyl-, and cyclopentadi-enyl copper have been isolated 86, 172, 246). Organocopper-isocyanide complexes are assumed to be intermediates in certain organic syntheses (245-252). Isocyanides also insert into the aryl-copper bond 281d) [Eq. (35)]. 

This allows comparisons of these independent copies and the derivation of an error level of 0.1 -0.15 A in atomic positions generally, 0.05-0.07A in copper-ligand bond lengths, and 3 5° in copper-bond angles. ... 

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