Cupric phenanthroline

Uric acid can be measured by its reduction of a metal complex, such as. cupric phenanthroline, neocuproine or bathocuproine. 

The oxidation of butanone-2, catalyzed by complexes of pyridine with cupric salts, appeared to be similar in its main features [191]. Butanone-2 catalytically oxidizes to acetic acid and acetaldehyde. The reaction proceeds through the enolization of ketone. Pyridine catalyzes the enolization of ketone. Enole is oxidized by complexes of Cu(II) with pyridine. The complexes Cu(II).Py with n = 2,3 are the most reactive. Similar results were provided by the study of butanone-2 catalytic oxidation with o-phenanthroline complexes, where Fe(III) and Mn(II) were used as catalysts [192-194],... 

The NO reduction of the Cu(II) complex Cu(dmp)2(H20)2+ (dmp = 2,9-dimethyl-l,10-phenanthroline) to give Cu(dmp)2 plus nitrite ion (Eq. (20)) has been studied in aqueous solution and various mixed solvents (42a). The reduction potential for Cu(dmp)2(H20)2+ (0.58 V vs. NHE in water) (48) is substantially more positive than those for most cupric complexes owing to steric repulsion between the 2,9-methyl substituents that provide a bias toward the tetrahedral coordination of Cu(I). The less crowded bis(l,10-phenanthroline) complex Cu(phen)2(H20)2+ is a weaker oxidant (0.18 V) (48). 

Jorgensen indicated that the absorption spectra of aqueous ethanolic solutions of cupric ion containing bipyridyl or phenanthroline (ratio 1 2) were compatible with the presence either of a cis-diaquobischelate cation or with a trigonal bipyramidal monoaquo species 409). The weak electrolyte behavior in nitrobenzene or nitromethane of deep blue Cu(bipy)2(C104)2 has been attributed to the following equilibrium ... 

Substituted bipyridines and phenanthrolines have been used as ligands for copper(II) ions. 4,4 6,6 -Tetramethyl-2,2 -bipyridyl(L) gives monomeric CuL(N03)2, two sulfato complexes, and a series [CuL2X]+C104, as well as forming copper(I) complexes readily (309). 2,9-Dimethyl-1,10-phenanthroline affords 1 1 complexes with cupric... 

Kochi s study of the copper salt-catalyzed oxidation of butenes by peresters (17) is interesting because the role of a ligand in controlling stereoselectivity was clearly demonstrated. This reaction, which involves the oxidation of allylic radicals by cupric ion, results in the formation of high yields of allylic ester in which the double bond is terminal, and it is described as occurring within a metal complex. When phenanthroline... 

Decarboxylation. Cohen and Schambach1 report that the usual copper metal-quinoline decarboxylation procedure is much slower than that using the cupric or cuprous salt of the acid (N2,180-200°). They also note that the rate is increased markedly by certain chelating agents such as 2,2 -dipyridyl (Eastman, Aldrich) and 1,10-phenanthroline (Eastman, Aldrich). The latter is more effective, but about twice as expensive. 

Breslow et al. 19) have investigated the mechanism of the divalent metal ion catalyzed hydration of 2-cyano-l,10-phenanthroline to the corresponding amide [see Eq. (7) below]. The cupric ion catalyzed reaction is extremely rapid lyz < 10 sec at 25°, pH 6—7). The Ni(II) and Zn(II) reactions, although slower, are greatly accelerated [the Ni(II) reaction by a factor of 10 ] in comparison to the rate of hydration observed in the absence of divalent metal ion catalysis. The reaction obeys a rate law which is second-order over all first-order with respect to hydroxide ion concentration, and first-order with respect to the 1 1 metal ion-substrate complex concentration. These authors suggest that the metal ion acts as a Lewis (general) add in activating the nitrile for external nucleophilic attack by hydroxide ion, as illustrated in Eq. (7) ... 

First, let us discuss the shapes of the chelated complexes. In most cases they are tetrahedral, but iron (both ferrous and ferric) forms octahedral complexes. However, the most remarkable contribution to selectivity is made by cupric ions which form planar complexes. This means that copper is uniquely sensitive to a type of steric effect imposed by bulky groups. Thus, in Table 11.2, the stability constants for the cupric complexes ofbipyridyl [11,19), phenanthroline [11.18), and folic acid lie below those of the corresponding nickel complexes, which is contrary to the natural order discussed in Section 11.2. 

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