Copper sources

In an x-ray diffraction experiment on a single crystal of sodium chloride, with the use of radiation from a copper source (X = 154 pm), constructive interference was observed at 0 = 11.2°. What is the spacing of the layers responsible for the diffraction ... 

Bolm et al. [106] have carefully studied the synthesis and the hganding ability of salen-like bis(sulfoximines). The chirahty which is indeed generally introduced via the use of chiral diamines in the salen series, is in sulfoximines present via the sulfur atom. They investigated the Diels-Alder cycloaddition between cyclopentadiene and acryloyl-2-oxazolidinones with various bis(sulfoximines) (see Scheme 42) and Cu(OTf)2 as the copper source [107]. 

Alkynylcoppers constitute a class of compounds relevant to several synthetic organic reactions,47 where they have been proposed as key intermediates. The interest in this area has supposed that the number of structurally characterized alkynylcopper complexes has considerably expanded in the last few years. The most common route toward alkynylcoppers is based on the reaction of a terminal alkyne with a copper source, either a salt or an organocopper compound (Equations (8) and (9)). 

Hong, C. Wagner, S. 2000. Inkjet printed copper source/drain metallization for amorphous silicon thin-film transistors. IEEE Electron Dev. Lett. 21 384-386. 

Though organocopper reagents such as Gilman-type or Lipshutz-type reagents have been widely used to date, there have been only a few reports concerning the catalytic use of a copper source. 

Figure 9.7 Map of some of the more important prehistoric copper sources in the eastern Mediterranean. (Adapted from Stos-Gale and Gale, 1990 Figure 1, in Thera and the Aegean World III, published with permission of the Thera Foundation, London, and the authors.)... 

Gale, N. H. and Stos-Gale, Z. A. (1982). Bronze Age copper sources in the Mediterranean a new approach. Science 216 11-19. 

The beneficial effect of added phosphine on the chemo- and stereoselectivity of the Sn2 substitution of propargyl oxiranes is demonstrated in the reaction of substrate 27 with lithium dimethylcyanocuprate in diethyl ether (Scheme 2.9). In the absence of the phosphine ligand, reduction of the substrate prevailed and attempts to shift the product ratio in favor of 29 by addition of methyl iodide (which should alkylate the presumable intermediate 24 [8k]) had almost no effect. In contrast, the desired substitution product 29 was formed with good chemo- and anti-stereoselectivity when tri-n-butylphosphine was present in the reaction mixture [25, 31]. Interestingly, this effect is strongly solvent dependent, since a complex product mixture was formed when THF was used instead of diethyl ether. With sulfur-containing copper sources such as copper bromide-dimethyl sulfide complex or copper 2-thiophenecarboxylate, however, addition of the phosphine caused the opposite effect, i.e. exclusive formation of the reduced allene 28. Hence the course and outcome of the SN2 substitution show a rather complex dependence on the reaction partners and conditions, which needs to be further elucidated. 

A possible example of the type of effect discussed above may be provided by the shift data for Fe in BaFeOs (8 = —0.29 with respect to copper source) and SrFeOs (8 = —0.17 with respect to copper source). Gallagher et at 23, 24) proposed that the larger size of the barium ion causes the lattice to expand, which in turn allows the Fe-O bond length to increase. They felt that this increased bond distance would decrease... 

Concentration profiles from the North Atlantic and North Pacific (a) phosphorus, (b) silicon, (c) iron, (d) nickel, (e) manganese, (f) cadmium, (g) zinc, and (h) copper. Source From Morel, F. M. M., and J. G. Hering (1993) Principles and Applications of Aquatic Chemistry. John Wiley Sons, p. 406. Data sources Bruland, K. W., and R. P. Franks (1983). Trace Metals in Seawater pp. 395-414, C. S., Wong, et al. Plenum Press and Bruland, K. W. (1980). Earth and Planetary Sciences Letters, 47, 176-198. 

Following reports of efficient Cu(I)-catalyzed alkyne/azide cycloaddition on solid phase and in solution by Meldal [42] and Sharpless [43], respectively, the formerly obscure Huisgen reaction soared to prominence as a versatile tool for covalent chemical ligation. The so-called click reaction can be catalyzed by a number of copper sources in a variety of media (Equation 9.14). 

Fig. 11. MBssbauer spectrum in the constant-acceleration mode. Zero velocity is with respect to 57Co in copper source. Figure according to Boudart el til. (215).

Fig. 18. Mossbauer spectra of Cr-Fc304 catalyst after room temperature exposure to air and COz/CO treatment at 703 K. (a) Spectrum in air at 296 K after sample has been stored in air. (b) Sample from (a) reduced in a C02/CO = 4 mixture at 703 K for 10 hr. Spectrum obtained in reaction mixture at 703 K. (c) After cooling (b) to 483 K. (d) After cooling (c) to 296 K. (e) Spectrum of a 0.001-in. Fe NBS standard foil at 296 K. Zero velocity is with respect to a 7Co in copper source. Reproduced from Tops0e and Boudart (96) with permission.

Fig. 26. Computer-fitted Mossbauer spectrum for small-particle Pt-Fe alloy. Peaks (1) and (4) form the outer surface doublet. Peaks (2) and (3) form the inner doublet. Zero velocity is with respect to a 57Co in copper source. Reproduced from Bartholomew and Boudart (195) with permission.

Flo. 37. Mossbauer spectra of small Fe304 particles exposed to air at room temperature and after C02/C0 treatment at 700 K. (a) and (b) are room temperature Mossbauer spectra of nonsupported magnetites exposed to air for 80 days (c) is sample (b) treated at 700 K with a C02/C0 mixture. Spectrum at room temperature. Zero velocity is with respect to a 57Co in copper source. Figure according to Tops0c el al. (237). 

Yellow light has a photon energy of 2 eV, and X-rays from a copper source, with a wavelength of 0.154 nm, a photon energy of about 8000 eV. This shows that at least 8000 V is needed to give electrons sufficient energy to produce these X-rays. 

Two processes are commonly used for the production of copper phthalocyanine the phthalic anhydride-urea process patented by ICI [33,34] and the I.G. Farben dinitrile process [48], Both can be carried out continuously or batchwise in a solvent or by melting the starting materials together (bake process). The type and amount of catalyst used are crucial for the yield. Especially effective as catalysts are molybdenum(iv) oxide and ammonium molybdate. Copper salts or copper powder is used as the copper source [35-37] use of copper(i) chloride results in a very smooth synthesis. Use of copper(i) chloride as starting material leads to the formation of small amounts of chloro CuPc. In the absence of base, especially in the bake process, up to 0.5 mol of chlorine can be introduced per mole of CuPc with CuCl, and up to 1 mol with CuCl2. 

Preparation for X-ray Analysis. Lattice constants are calculated from patterns obtained on powder samples with a Norelco diffractometer using monochromatic radiation (AMR-202 Focusing Monochromator) from a high-intensity copper source. The crystals are powdered with a diamond mortar and pestle, and the powder passed through a 74-/ sieve. Accurate lattice constants are calculated from the x-ray data. 

In the same vein, Koslowski and co-workers have published a study using chiral 1,5-diazadecalin complex 225, a species that directs binaphthol formation with excellent enan-tioselectivity [149]. The use of Cul or Cu(OTf) as a copper source in this procedure contributes to the excellent yields (85 %) and high enantiomeric excesses ( 90 %) (Scheme 59). Substituents on the nitrogens of 225 or changes in the copper source resulted in lower yields and/or lower enantioselectivities. Other naphthol substrates have been subjected to these conditions, but both the yields and enantioselectivities were diminished, showing the importance of the ester moiety with regard to the efficiency of the reaction (Table 40). 

Scheme 59. The effect of the copper source on the enantioselectivity of the dimerization of 68f, as mediated by chiral amine 225.

---