Copper intermediate species

It is reported that the intermediate species in the CujO-Icrt-BuNC reaction system can undergo reactions with cyclopentadiene or with indene. The products obtained are C5HjCu(CNBu ) and indenylCu(CNBu )3 132). The postulate that a copper(I) isocyanide complex is the reaction intermediate here is reasonable. 

As a part of their ongoing investigations into the reaction of dioxygen with copper(I) complexes to identify copper-superoxo/peroxo intermediate species, Schindler and co-workers51-53 have also provided examples of a number of mononuclear copper(II) complexes (Table 1) (as well as copper(I) Section 6.6.4.2.1). 

Potassium tert-butoxide reacts with copper iodide to generate a copper / -butoxide species 98 (Scheme 29). Activation of the alkyne 94 by this copper catalyst (intermediate 96) allows the enolate attack to afford the cyclic... 

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],... 

As a consequence, H02 /02- are involved as intermediate species in aquatic redox cycles of metals such as copper or iron [36]. There are many different possible pathways of formation of superoxide [7,37], only two of which... 

Polarographic behavior of copper(II) and copper(I) species in the presence of various ligands has been investigated (154, 215, 258, 279, 343). In some instances, however, no copper(I) intermediate was observed in the reduction to copper amalgam at the electrode, e.g., at low concentrations of 1,2-diaminoethane (270) or similar diamines (205) this is in keeping with a value of 4 x 10 for the equilibrium constant (33, 291) of the reaction... 

Electroless deposition of Au in KAu(CN)2 -I- HF can be controlled by both the kinetic process and the diffusion process. The deposition is a two-step process, with initial diffusion-limited deposition of the intermediate species, followed by surface-limited reduction of this species. For electroless deposition of Pt, it has been reported that the rate-determining step is the deposition on n-Si, whereas it is the dissolution of silicon on p-Si. Electroless copper deposition does not occur on Si02-covered silicon surface due to the lack of anodic dissolution of silicon In a non-HF solution, the deposition of copper on a bare silicon surface results in the formation of oxide aroimd the metal particles. In HF solutions, the deposition of copper proceeds very slowly in the dark on both p-Si and n-Si samples due to the lack of carriers. The... 

The exact mechanistic pathway of the Ullmann coupling is not known. There are two main pathways possible 1) formation of aryl radicals or 2) the formation of aryl copper [ArCu, ArCu " and ArCu " ] intermediates. Currently the most widely accepted mechanism assumes the formation of aryl copper intermediates, since many of these species can be isolated and they can react with aryl halides to give biaryls. 

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