- Temperature and pressure effects on the outer-sphere electron-transfer reaction between hexacyanoferrate(II) and pentaamminecobalt(III) complexes in aqueous solution. Comparison of experimental and theoretical volumes of activation
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The kinetics of a series of outer-sphere electron-transfer reactions of the type Co(NH3)4(NH2R)X(3-n)+ + Fe(CN)64- → Co2+ + 4NH3 + NH2R + Xn- + Fe(CN)63- (X = N3-, R = H; X = Cl-, R = H, CH3, i-C4H9) were studied as a function of temperature and pressure. It was possible to separate the ion-pair formation constant and the electron-transfer rate constant in a kinetic way, and the corresponding thermodynamic and activation parameters were determined. For the electron-transfer process, the rate and activation parameters lie in the ranges 0.06 ≤ k × 102 ≤ 20 s-1, 84 ≤ ΔH? ≤ 118 kJ mol-1, +11 ≤ ΔS? ≤ 113 J K-1 mol-1, and +19 ≤ ΔV? ≤ +34 cm3 mol-1. The experimentally observed activation volumes are in good agreement with those predicted theoretically on the basis of an average λ? value of 0.48 ± 0.07. The results are discussed in reference to related studies reported in the literature.
- Krack,Van Eldik
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p. 1700 - 1704
(2008/10/08)
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- Effect of Axially Bound Anions on the Electroreduction of Tin(IV) Porphyrins in Tetrahydrofuran
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The spectroscopic characterization and electrochemistry of SnL(X)2 is presented where L is the dianion of tetra-p-tolylporphyrin or tetra-m-tolylporphyrin and X is CIO4-, Br-, Cl-, F-, or OH-.In all cases, electroreduction leads to porphyrin ? anion radicals and dianions which were characterized in tetrahydrofuran by spectroelectrochemistry and e.s.r. spectroscopy.Dissociation of one CIO4- ion from SnL(CIO4)2 occurs before electroreduction of the complex but no dissociation is observed either before or after electroreduction of SnL(F)2 or SnL(OH)2.In contrast, one Br- ion dissociates after the first electron addition to SnL(Br)2 while one Cl- ion dissociates from SnCl(Cl)2 after the second electroreduction of this complex.
- Kadish, Karl M.,Xu, Quan Yun Y.,Maiya, G, Bhaskar,Barbe, Jean-Michel,Guilard, Roger
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p. 1531 - 1536
(2007/10/02)
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- MASS-SPECTROMETRIC AND QUANTUM-CHEMICAL INVESTIGATION OF THERMOCHEMICAL CHARACTERISTICS OF CHLORINE OXIDES
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An electron impact technique has been used for the direct determination of the ionization potential (IP) of the ClO3 radical and the electron affinity (EA) of the ClO3 and ClO4 radicals.By means of quantum-chemical calculations taking into account configu
- Alekseev, V. I.,Zyubina, T. S.,Zyubin, A. S.,Baluev, A. V.
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p. 2092 - 2096
(2007/10/02)
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- Trivalent germanium cations in solution
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Reaction of R3GeH (R = Me, Ph) with trityl perchlorate produces free germylenium cations (R3Ge+) in dilute sulfolane solution. Conductivities, cryoscopic molecular weights, 35Cl line widths, and 35Cl
- Lambert, Joseph B.,Schilf, Wojciech
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p. 1659 - 1660
(2008/10/08)
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