Transfert couplé électron/proton et coupure de liaison dans des systèmes bio-inspirés

Viviane Hajj 1
1 Transfert d'électron et bouleversement moléculaire
LEM - Laboratoire d'electrochimie moleculaire
Abstract : The electron transfer associated with proton transfer or bond breaking is an important process often presented in natural and biological systems. Understanding the mechanistic issues involved in the operation of these systems allows one to exploit and imitate them. Two bio-inspired systems have been studied by direct electrochemistry, the oxidation of a guanine paired to a cytosine with hydrogen bonds and the reduction of a cycloperoxide assisted by the presence of a proton donor group. The match between DNA bases through hydrogen bonding has no effect on the kinetic and thermodynamic of the oxidation of a guanine. The reaction is kinetically controlled by the first stage of electronic transfer and the mechanism involved is sequential. The reductive cleavage of the O-O bond of the cycloperoxide assisted by the presence of a proton donor group is compared to another system in which the carboxylic acid group is replaced by an ester function. An offset of 700 mV was observed between the peak potentials of both compounds indicating that the gain offered by the protonation step is expressed in the kinetic of the reaction. Consequently the dissociative electron transfer and the proton transfer are all concerted. A new simplified kinetic model was established to describe the dynamics of such a mechanism called " all in concert ".
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Theses
Theoretical and/or physical chemistry. Université Paris-Diderot - Paris VII, 2011. French


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Submitted on : Wednesday, June 27, 2012 - 10:52:39 AM
Last modification on : Wednesday, October 29, 2014 - 1:28:28 PM

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Viviane Hajj. Transfert couplé électron/proton et coupure de liaison dans des systèmes bio-inspirés. Theoretical and/or physical chemistry. Université Paris-Diderot - Paris VII, 2011. French. <tel-00712330>

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