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Variations autour d'une porphyrine à anse phénanthroline : un site distal dynamique

Abstract : The purpose of this work was to prepare efficient models of cytochrome P450, hemoglobin and cytochrome c oxidase, by various synthetic modifications on a phenanthroline-strapped porphyrin (Porphen). In particular, a new model of cytochrome c oxidase was analyzed here. This compound was obtained by substitution of both meso positions of a Zn-Porphen. Dynamics phenoma were observed and analyzed by 1H NMR, showing the presence of atropoisomers and coordination-decoordination of the proximal pyridine on zinc. Zinc was then replaced by iron, which allows the coordination of a sixth exogenous ligand in the dynamic distal site. The evolution of the complexes’ geometry was monitored by UV-Visible spectrophotometry and EPR. In the presence of imidazolesligands, complexes [1 receptor/ 1 substrate] were observed in all cases. Our model’s high affinity for dioxygen was shown by UV-Visible and 1H NMR spectroscopy and Raman resonance. In UV-Visible and NMR studies, the reversibility of dioxygen binding was demonstrated by replacement with CO.The versatility of this new architecture was demonstrated during IR studies by the relative flexibility of the CO binding in the distal site. This versatility also led to surprisingly behavior in electrochemistry, where the reduction of iron(III) and the oxidation of copper(I) were easier in the presence of O2. In electrocatalysis, the reduction of O2 by this new cytochrome c oxidase model was not easier in terms of potentiel, but was efficient in a 4-electrons mechanism.
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Submitted on : Tuesday, November 20, 2012 - 11:32:13 AM
Last modification on : Friday, August 5, 2022 - 9:27:47 AM
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  • HAL Id : tel-00754973, version 1



Pauline Vorburger. Variations autour d'une porphyrine à anse phénanthroline : un site distal dynamique. Sciences agricoles. Université de Strasbourg, 2012. Français. ⟨NNT : 2012STRAF004⟩. ⟨tel-00754973⟩



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