Copper self-exchange rate constant

Blue copper proteins, 36 323, 377-378, see also Azurin Plastocyanin active site protonations, 36 396-398 charge, 36 398-401 classification, 36 378-379 comparison with rubredoxin, 36 404 coordinated amino acid spacing, 36 399 cucumber basic protein, 36 390 electron transfer routes, 36 403-404 electron transport, 36 378 EXAFS studies, 36 390-391 functional role, 36 382-383 occurrence, 36 379-382 properties, 36 380 pseudoazurin, 36 389-390 reduction potentials, 36 393-396 self-exchange rate constants, 36 401-403 UV-VIS spectra, 36 391-393 Blue species... 

Self-exchange rate constants, blue copper pro-tiens, 36 401-403... 

Table IV. Electron Transfer Cross-Reaction and Self-Exchange Rate Constants for Blue Copper Proteins (25°, /aO.IM, pH 7)a...

Electron Self-Exchange Rate Constants kese (298K) for Blue Copper Proteins Retrieved from NMR Spectra... 

Self-Exchange Rate Constants for Cu(I) and Cu(II) States of Different Blue Copper Proteins"... 

A further influence on electron exchange is the ligand type present. Thus with bidentate aromatic 2,2 -bipyridine and 1,10-phenanthroline ligands (L), the [RuL3] + + self-exchange rate constants are 1 x 10 sec (95, 96). In the case of the copper proteins the imidazole and S-donor ligands presumably have similar beneficial effects. 

The electron self-exchange rate constants of proteins are considerably larger than those of the inorganic copper complexes (Tables IV and V) (11,25,106,111). This is attributed to the large changes in the coordination sphere structures of the Cu(II) and Cu(I) inorganic complexes in comparison to the relative rigid active sites of the proteins. 

Electron Self-exchange Rate Constants of Blue Copper Proteins... 

The kinetic behavior of the reductions of several Cu(II)N2S2 complexes, containing thioether/pyridyl chelate ligands, by ferrocene and l,r-dimethyl-ferrocene in acetonitrile points to the formation of a precursor complex prior to electron transfer.The rate constant for the oxidation of (hydroxyethyl)-ferrocene by [2-pyridyl(methylbis(2-ethyl)thioethyl)amine]copper(II) yields a [Cu(pmas)] self-exchange rate constant of 47 M s from the Marcus theory relation.The addition of NJ increases the rate of oxidation (F" and I" have no effect) by shifting the reduction potential upon the formation of [Cu(pmas)N3] and Cu(pmas)(N3)2 (NJ displacement of a thioether sulfur occurs in the latter species). The application of the Marcus relationship to the reductions of the [l,8-bis(2-pyridyl)-3,6-dithiaoctane]copper(II) complex by a series of Ru(II) ammine and bipyridyl complexes in 50% aqueous CH3OH yields a self-exchange rate constant of 0.63 s for the [Cu(pdto)] couple. " From the rate... 

The electron self-exchange rates for the [l,7-bis(5-methylimidazol-4-yl)-2,6-dithiaheptane]copper(I)/(II) couple in DMSO have been determined by H NMR line broadening as a function of temperature, with fcn = 4 x 10 M s" at 28 An electron self-exchange rate constant of 1.3 x 10" M s has been measured for the [Cu((imidH)2DAP)] /" couple (imidH)2DAP = 2,6-bis[l-((2-... 

Marcus theory has been used to interpret the reactions of cytochromes c and blue copper proteins. For thirteen protein-protein electron-transfer reactions, the data can be fitted with the self-exchange rate constants of 2.8 x 10 s ... 

The electron self-exchange rate constants for two Cu(I)/Cu(II) complex couples, synthesized as models for active sites of copper metalloproteins, have been determined in acetonitrile using NMR techniques. An upper limit of... 

It has been recognized that sulfur donors aid the stabilization of Cu(i) in aqueous solution (Patterson Holm, 1975). In a substantial study, the Cu(ii)/Cu(i) potentials and self-exchange electron transfer rate constants have been investigated for a number of copper complexes of cyclic poly-thioether ligands (Rorabacher et al., 1983). In all cases, these macrocycles produced the expected stabilization of the Cu(i) ion in aqueous solution. For a range of macrocyclic S4-donor complexes of type... 

The coordination of copper ion by macrocyclic quadri- and quinque-dentate thi-oethers makes the Cu VCu reduction process easier, and also increases the rate of the redox self-exchange electron transfer process [55]. For example, [Cu(13-aneS4)] undergoes a one-electron reduction at 0.52 V versus NHE [58] (cf. E°(Cu /Cu ) = 0.15V versus NHE for the aquated ion in water) and the rate constant for the corresponding self-exchange electron transfer is 3 x 10 s [59] (to be compared... 

A mechanism involving the polarization of the ascorbate ligand by a Cu(II) central ion was proposed (138), though the involvement of Cu(I) cannot be ruled out (139). All these reactions proceed via the inner-sphere mechanism however, the copper-catalyzed reduction of superoxide boimd to a binuclear cobalt(III) complex by 2-aminoethanethiol proceeds via the outer-sphere mechanism (140). This is attributed to the effect of 2-aminoethanethiol as a hgand on the rate constant of the Cu(ll/1) electron self-exchange reaction which is suggested to proceed via the gated mechanism. 

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