Cu 2 oxidant

Using a catalyst system of PdCl2, CuCH, HCl, and O2, the internal alkyne 20 is carbonylated at room temperature and 1 atm to give unsaturated esters[19]. This apparently oxidizing system leads to non-oxidative cu-hydroesterilica-tion. With terminal alkynes, however, oxidative carbonylation is observed. 

Oxidation of the aldehyde group of an aldose to form a carboxyUc acid or carboxyUc acid anion is often used analytically to determine the amount of reducing sugar. The Benedict and Fehling methods measure the amount of reducing sugar present in a fluid. In these reactions, the oxidant, Cu ", is reduced to Cu". Cu" precipitates as CU2O, which can be measured in a variety of ways. In the ToUens test, Ag" is reduced to Ag. ... 

Phenylhydrazides have been prepared from amino acid esters and phenylhydrazine in 70% yield they are cleaved by oxidation [Cu(OAc)2, 95°, 10 min, 67% yield FeCyi NHCl, 96°, 14 min, 85% yield ]. 

Kupferoxyd, n. cupric oxide, copper(II) oxide, -ammoniak, n. ammoniacal copper oxide, cu-prammonium. -ammoniakkunstseide, -am-moniakzellulose, /. cuprammonium rayon, -hydrat, n. cupric hydroxide, copper(II) hydroxide. -salz, n. cupric salt, copper(II) salt. 

Deoxygenation can oxidize the metal surfaces. It was found that the partially oxidized Cu surface was the most active in the isomerization of methy-loxirane to propanal.288 The same is true for Ni. Therefore, it is very likely that the metal ions produced by the oxidation of copper or nickel surfaces during deoxygenation play an important role in isomerization to aldehyde. 

A Cu(s) will displace metal ions of a metal less active than copper. Silver ion is one example. Oxidation Cu(s)-> Cu2+ (aq)+2e -E° = -0.340V (from Table 21.1)... 

Alteration-Mineralization Pattern and Geochemical Characteristics of Samli (Balikesir) Fe-Oxide-Cu-(Au) Deposit, Turkey... 

Keywords Iron oxide-Cu-Au deposits, Na-Ca alteration, amlipluton, amli, Balikesir... 

The Na-Ca and K-Fe-(Ca) alteration assemblage hosting iron-oxide, copper and gold mineralization and spatial and temporal relationship between mineralization and alteration, as well as the oxide and sulfide mineralogy at amli (Balikesir) suggest that it has characteristics more akin to Fe-oxide-Cu-Au systems. 

Comparison of results using xanthate and TY3 collector using dolomitic oxide Cu/Co ores... 

The second class of dioxygen carriers is that of haemocyanins. These proteins, which contain a binuclear Cu(I) site (thus in the oxidized Cu(II) met form they belong to the so-called Type 3 copper proteins , which contain an EPR-silent dicopper active site), regulate dioxygen transport in the respiration of arthropods and molluscs. Figures 7 and 8 show... 

Interest is mounting in this state, promoted once again by its possible implication in biological systems. Galactose oxidase, for example, is a copper enzyme which catalyses the oxidation of galactose to the corresponding aldehyde. The tervalent oxidation state may be prepared from Cu(II) by chemical, anodic and radical oxidation. Cu(III) complexes of peptides and macrocycles have been most studied, particularly from a mechanistic viewpoint. The oxidation of I" by Cu(III)-deprotonated peptide complexes and by imine-oxime complexes have a similar rate law... 

These observations highlighted the necessity of sufficient concentration of oxidized Cu for sustainable methylation activity. Only on x = 0.5 (after 24h reaction run) the (Cu+Zn)/Fe ratio was maintained at 1, and hence an extended catalytic activity was observed (Figure 17c). It is clear that not a single metal ion, but the presence of an equal amoimt of Cu and Zn on the... 

Copper proteins have been classified according to their spectroscopic properties (Malkin and Malmstrbm, 1970 Fee, 1975) as type I, II, or III. Type I blue copper proteins are characterized by an extraordinarily intense absorption near 600 nm and by unusually small hyperfine coupling constants for the paramagnetic [oxidized Cu(II)] form of the protein. 

The LFMM FF for the oxidized Cu(II) centers was designed around suitable homoleptic species, viz., [Cu(imidazole)4]2+, [Cu(SCH3)4]2-, [Cu(S(CH3)2)4]2+, and [Cu(0=CH2)4]2+ (37). These complexes represent models for Cu-histidine, Cu-cysteine, Cu-methionine, and Cu-glutamine O/peptide respectively. Only the first of these species is known experimentally. However, it is amply documented that DFT gives excellent structures for metal complexes (64,65) so we can access the remaining species computationally (Fig. 20). 

---