Copper pyridine

Mohler has just shown that copper, pyridine and air oxidize benzoin to benzoic acid. Also, the same oxidation takes place in the absence of copper. 

Electro-oxidative polymerization of 2,6-disubstituted phenols is listed in Table I, with the polymerizations catalyzed by the copper-pyridine complex and oxidized by lead dioxide. 2,6-Dimethylphenol was electro-oxidatively polymerized to yield poly(2,6-dimethylphen-yleneoxide) with a molecular weight of 10000, as was attained by other polymerization methods. The NMR and IR spectra were in complete agreement with those measured for the other polymerization... 

Figure 3. Relationship between the polymer yield and the molecular weight, o Polymerization catalyzed by the copper-pyridine complex. Electrolysis...

The refered oxidative polymerization of phenols with the copper-pyridine catalyst was carried out as in lit. (7,8). 

Older examples are coupling of phenols catalyzed by Cu(I)-pyridine in which the relative amounts of carbon-carbon and carbon-oxygen coupling are controlled by the copper/pyridine ratio (16) (Reaction 10)... 

In ammoniacal solutions of copper salts, the oxidation products are likely to contain nitrogen thus, hexoses give oxalic acid, imidazoles, hydrogen cyanide, and urea. Kinetic studies have been reported for the reaction of Cu(II) in the presence of ammonia with maltose, lactose, melibiose, and cellobiose.190 For the oxidation by tetraamminecopper(II) in ammoniacal and buffered media the rate of reaction is first order in disaccharide concentration, order one-half in ammonia concentration, but it is independent of Cu(II) concentration. The reaction rate is decreased by the addition of ammonium chloride, because of the common ion effect. These kinetics suggested mechanisms involving an intermediate enediolate ion, with the rate of reaction being equal to the rate of enolization.191 A similar mechanism has been proposed for the oxidation of D-fructose by a copper-pyridine complex in an excess of pyridine.192... 

Ni(C6HsN)4(NCS)2]6,18 81 has been recommended for the ther-mogravimetric determination of nickel or thiocyanate.82-88 The emerald-green chloroform-soluble copper complex [Cu(C5H5N)2-(NCS)2] has been suggested for the detection of copper, pyridine, or thiocyanate.84... 

The blue complex is stable in the presence of a moderate excess of acetic acid the reaction can therefore be applied to the detection of cyanates in alkaline solution. The solution to be tested is added to the copper-pyridine-chloroform mixture, acetic acid added slowly and the solution shaken vigorously after each addition. As soon as the solution is neutral, the chloroform will assume a blue colour. 

Y. Ukisu, A. Kazusaka, and M. Nomura, Preparation and Catalysis of a Copper-Pyridine Complex Encapsulated into a Zeolite Supercage. J.Mol. Catal., 1991, 70, 165-174. 

W. Bohlmann, K. Schandert, A. Poppl, and H.-C. Semmelhack, Synthesis and Electron Spin Resonance Studies of MCM-41 Doped with Copper Pyridine Complexes. Zeolites, 1997,19, 297-304. 

The further coordination of copper pyridine complexes with other ligands in methanol has been studied by investigation the absorption spectra and by studying equilibria of cupric nitrate and pyridine in methanol in the presence of solid Cu(F r) (NOj)j. If addition of a ligand X to such a system leads to... 

Although pyridine solutions of the peroxo complex were stable over long periods of time, attempts to isolate a soUd always resulted in the precipitation of black CuO. Thus, excess pyridine was necessary to stabilize the peroxo complex. Observations on the stoichiometric effect of varying copper/pyridine ratios, suggest that the minimum number of pyridine hgands required is 2. These results are consistent with the formulation of the catalytically active brown species, as [(py)nCuOOCu(py) ]( >2) in the reaction of copper(l) chloride with oxygen in pyridine. 

Copper pyridine 3-Hydroxypyrazole ring 3-Hydroxy-lH-pyrazolo[3,4-b]pyridines... 

In their experiments a Cu++-morpholine complex is used as a catalyst. The solvent is methanol. Various metals were tested Ti, V, Cr, Fe, Mn, Co, Ni, Mo, Ag, Cd, Sn, Sb, Ce, W, Au, Hg, Pt, Tl, Pb, Bi, and U. None are active. Copper-collidine and copper-pyridine complexes are used for the oxidation of a number of naphthols, in contrast with monophenols requiring morpholine complexes. 

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