Copper-pyridine complex

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...

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... 

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... 

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. 

In the context of copper catalysis in important synthetic dediazoniations of arene-diazonium ions, Starkey s group (Bolth et al., 1943, Whaley and Starkey, 1946) isolated blue pyridine complexes with the constitution ArCu(C5H5N)3 by adding copper powder to pyridine solutions of ArNjBF4. However, it is unlikely that arylcopper is a relevant intermediate in these reactions (see Sec. 8.6). 

Carboxylic acids, a-bromination of 55, 31 CARBOXYLIC ACID CHLORIDES, ketones from, 55, 122 CARBYLAMINE REACTION, 55, 96 Ceric ammonium nitrate [Ammonium hexa mtrocerate(IV)[, 55, 43 Chlorine, 55, 33, 35, 63 CHROMIUM TRIOXIDE-PYRIDINE COMPLEX, preparation in situ, 55, 84 Cinnamomtnle, a-phenyl- [2-Propeneni-tnle 2,3-diphenyl-], 55, 92 Copper(l) iodide, 55, 105, 123, 124 Copper thiophenoxide [Benzenethiol, copper(I) salt], 55, 123 CYCLIZATION, free radical, 55, 57 CYCLOBUTADIENE, 55, 43 Cyclobutadieneiron tricarbonyl [Iron, tn-carbonyl(r)4-l,3-cyclo-butadiene)-], 55,43... 

The Ullman reaction has long been known as a method for the synthesis of aromatic ethers by the reaction of a phenol with an aromatic halide in the presence of a copper compound as a catalyst. It is a variation on the nucleophilic substitution reaction since a phenolic salt reacts with the halide. Nonactivated aromatic halides can be used in the synthesis of poly(arylene edier)s, dius providing a way of obtaining structures not available by the conventional nucleophilic route. The ease of halogen displacement was found to be the reverse of that observed for activated nucleophilic substitution reaction, that is, I > Br > Cl F. The polymerizations are conducted in benzophenone with a cuprous chloride-pyridine complex as a catalyst. Bromine compounds are the favored reactants.53,124 127 Poly(arylene ether)s have been prepared by Ullman coupling of bisphenols and... 

CHROMIUM TRIOXIDE-PYRIDINE COMPLEX, preparation in situ, 55, 84 Chrysene, 58,15, 16 fzans-Cinnamaldehyde, 57, 85 Cinnamaldehyde dimethylacetal, 57, 84 Cinnamyl alcohol, 56,105 58, 9 2-Cinnamylthio-2-thiazoline, 56, 82 Citric acid, 58,43 Citronellal, 58, 107, 112 Cleavage of methyl ethers with iodotri-methylsilane, 59, 35 Cobalt(II) acetylacetonate, 57, 13 Conjugate addition of aryl aldehydes, 59, 53 Copper (I) bromide, 58, 52, 54, 56 59,123 COPPER CATALYZED ARYLATION OF /3-DlCARBONYL COMPOUNDS, 58, 52 Copper (I) chloride, 57, 34 Copper (II) chloride, 56, 10 Copper(I) iodide, 55, 105, 123, 124 Copper(I) oxide, 59, 206 Copper(ll) oxide, 56, 10 Copper salts of carboxylic acids, 59, 127 Copper(l) thiophenoxide, 55, 123 59, 210 Copper(l) trifluoromethanesulfonate, 59, 202... 

Copper(II) complexes have been prepared with the 2-acetylpyridine N-oxide 3-azabicyclo[3.2.2.]nonylthiosemicarbazone, 25, and bonding occurs via the pyridine N-oxide oxygen, azomethine nitrogen and thiol sulfur [128]. Based on electronic and ESR spectra, bonding to copper(II) of uninegative, tridentate 25-H is considerably weaker than the related 2-acetylpyridine thiosemicarbazone, 4-H. The other copper(II) complexes reported to date have been prepared... 

Table 5 Stereochemistries of copper(I) complexes of pyridine-based ligands.3...

The presence of substituents and the use of pyridine as solvent changes the ratio of ligands. In the case of donor or weak acceptor substituents the formation of complexes with Cu(I) takes place, stable crystalline compounds being obtained only in the presence of pyridine. In all the cases copper forms complexes with one phosphorus ligand but the number of pyridine molecules varies from 1 to 3 [Eq. (155)]. 

Copper(ii) complexes of 8-amino-7-hydroxy-4-methylcoumarin, 1,10-phenanthroline-2-carboxamide, 2-pyridone, 2,3-di-(2-pyridine N-oxide)-quinoxaline," pyridine carboxylates, l-(2 -pyridyl)-2-azonaphthol, and l-(2 -benzothiazolyl)-2-azonaphthol have also been reported. 

Poly(2,6-dimethylphenylene ether) can be prepared by dehydrogenation of 2,6-dimethylphenol with oxygen in the presence of copper(l) chloride/pyridine as catalyst at room temperature. It is known that the mechanism involves a stepwise reaction, probably proceeding via a copper phenolate complex that is then dehydrogenated. 

---