Anion copper-containing complex

Finally, it should be noted that there is a series of copper-containing complex compounds with superstructures based on anion-defident perovskite type. These have been the subject of intense research in recent years, because of their remarkable high-temperature superconducting properties, and many appropriate reviews have been produced. 

There are no mechanistic details known from intermediates of copper, like we have seen in the studies on metathesis, where both metal alkylidene complexes and metallacyclobutanes that are active catalysts have been isolated and characterised. The copper catalyst must fulfil two roles, first it must decompose the diazo compound in the carbene and dinitrogen and secondly it must transfer the carbene fragment to an alkene. Copper carbene species, if involved, must be rather unstable, but yet in view of the enantioselective effect of the ligands on copper, clearly the carbene fragment must be coordinated to copper. It is generally believed that the copper carbene complex is rather a copper carbenoid complex, as the highly reactive species has reactivities very similar to free carbenes. It has not the character of a metal-alkylidene complex that we have encountered on the left-hand-side of the periodic table in metathesis (Chapter 16). Carbene-copper species have been observed in situ (in a neutral copper species containing an iminophosphanamide as the anion), but they are still very rare [9],... 

Copper-fluoro complexes are more frequently encountered for the Cu ion than for the Cu ion, although not to the extent one might predict. Fluoride bound in a monodentate fashion is extremely rare, while bridging fluoride ligands and coordinated F-containing anions, such as BF4 and PFe", are more coimnon. 8imilar to that found for Cu, chloride is found extensively in Cu chemistry, followed distantly by bromide. Iodide coordination to Cu is, as one might expect, limited seen only in complexes such as [Cu(bipy)I]I. The section on binary and simple compounds above also discusses a number of Cu halide compounds. 

The inner membrane of mitochondria is the site of respiratory electron transport and within the inner membrane and the intermembrane space (IMS) of mitochondria are two important copper containing enzymes. First, cytochrome c oxidase (COX) represents the terminal electron acceptor in the respiratory chain and two subunits of this large complex enzyme contain copper sites. A second enzyme in the mitochondria that requires copper is SODl, as described above. Although the vast majority of SODl is cytosolic, a small fraction of this enzyme enters the IMS of the mitochondria where it is believed to directly scavenge superoxide anions produced as a by-product of the electron transport chain. 

Solutions of salt-like substances do not always contain simple hydrated ions. For example, some solutions of chromium(III) salts are green. These contain complexes with the anions of the salt, e.g. [CrCl2(H20)4]. Freezing points of copper sulfate solutions indicate that, except at very low concentrations, most of the salt is present, not as Cu and S04 ions, but as [CuS04(H20) ] ... 

The copper pyrophosphate bath contains complex anions such as Cu(P207)2" and CuP207", and the operating pH and CU/P2O7 ratio are fairly critical. Below pH 7, precipitation of CU2P2O7 or CUH2P2O7 occurs, and above pH 11, Cu(OH)2. 

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