- Two-electron oxidation of N,N,N′,N′-tetramethylphenylenediamine with a chromium(v) salen complex
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The oxidation of tetramethylphenylenediamine (TMPD) with (salen)Cr VO+ generates initially the 2-electron product TMPD 2+, followed by the reaction with excess TMPD to yield the radical cation, TMPD+. The kineti
- Chaka, Gezahegn,Bakac, Andreja
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p. 318 - 321
(2009/04/19)
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- Application of Marcus cross-relation to mixed inorganic-organic redox couples. A stopped-flow study of the oxidation of N,N,N′,N′-tetramethyl-p-phenylenediamine with various oxidants
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The rate constants of the oxidation of N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPPD) are measured in water by means of stopped-flow techniques using different inorganic ions, like Fe(CN)63-, MnO4-, Co(NH3)63+, Ru(OH)63+. The rates do not depend on the different oxidation potentials, but can be correlated well with calculated rate constants from the Marcus cross-relation. The electron self-exchange rates of the inorganic oxidants range over nine orders of magnitude. Measurements were performed at T = 293 K within a pH-range of 7-9.
- Grampp, Guenter,Landgraf, Stephan,Sabou, Dana,Dvoranova, Dana
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p. 178 - 180
(2007/10/03)
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- Mechanism and Kinetics of the Photocatalyzed Oxidation of p-Phenylenediamines by Peroxydisulfate in the Presence of Tri-2,2'-bipyridylylruthenium(II)
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The autocatalytic oxidation of p-phenylenediamines with peroxydisulfate can be strongly enhanced by irradiation in the presence of tri-2.2'-bipyridylylruthenium(II).Ru(bpy)32+ acts as photosensitizer and photocatalyst.First, Ru(bpy)33+ is formed by quenching excited Ru*(bpy)32+ with S2O82-.Then the ruthenium(III) complex oxidizes p-phenylenediamine.The resulting Ru(bpy)32+ can start the cycle again.The photocatalytic oxidation of N,N-diethyl-p-phenylenediamine as well as the dark reactions were studied with stopped-flow techniques.The mechanism of this complex reaction is discussed in detail.
- Nickel, Ulrich,Chen, Yao-Hong,Schneider, Siegfried,Silva, Maria I.,Burrows, Hugh D.,Formosinho, Sebastiao J.
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p. 2883 - 2888
(2007/10/02)
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- INVESTIGATION OF ELECTRON TRANSFER REACTIONS BETWEEN AROMATIC AND QUINOID SYSTEMS.
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A classical organic redox reaction is the conversion of an aromatic compound from its reduced form R to a semioxidized state S, and further to a totally oxidized (quinoid) species T. Complex redox systems are present in a reaction of quinoid and aromatic forms derived from different parent compounds. In this case, the exchange of one or two electrons in one step between T and R can be distinguished experimentally. These reactions were investigated in a stopped-flow apparatus with optical detection. In the system N,N,N prime ,N prime -tetramethyl-para-phenylene-diamine/N,N-dimethyl-para- phenylenediamine the rate constants for all elementary reactions have been determined. Protonated, and unprotonated R were found to be reactive.
- Goez,Jaenicke,Nickel
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p. 459 - 467
(2007/10/02)
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