EPR, ENDOR, and HYSCORE Study of the ...
Type de document :
Article dans une revue scientifique: Article original
DOI :
URL permanente :
Titre :
EPR, ENDOR, and HYSCORE Study of the Structure and the Stability of Vanadyl−Porphyrin Complexes Encapsulated in Silica: Potential Paramagnetic Biomarkers for the Origin of Life
Auteur(s) :
Gourier, Didier [Auteur]
Delpoux, Olivier [Auteur]
Bonduelle, Audrey [Auteur]
Binet, Laurent [Auteur]
Ciofini, Ilaria [Auteur]
Vezin, Herve [Auteur]
Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement (LASIRE) - UMR 8516
Delpoux, Olivier [Auteur]
Bonduelle, Audrey [Auteur]
Binet, Laurent [Auteur]
Ciofini, Ilaria [Auteur]
Vezin, Herve [Auteur]
Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement (LASIRE) - UMR 8516
Titre de la revue :
The Journal of Physical Chemistry B
Nom court de la revue :
J. Phys. Chem. B
Numéro :
114
Pagination :
3714-3725
Éditeur :
American Chemical Society (ACS)
Date de publication :
2010-02-22
ISSN :
1520-6106
Mot(s)-clé(s) en anglais :
Degradation
Anions
Pyrroles
Silica
Electron paramagnetic resonance spectroscopy
Anions
Pyrroles
Silica
Electron paramagnetic resonance spectroscopy
Discipline(s) HAL :
Chimie/Chimie théorique et/ou physique
Résumé en anglais : [en]
The possibility of using vanadyl ions as paramagnetic biomarkers for the identification of traces of primitive life fossilized in silica rocks is studied by cw-EPR, ENDOR, HYSCORE, and DFT calculations. It is well-known ...
Lire la suite >The possibility of using vanadyl ions as paramagnetic biomarkers for the identification of traces of primitive life fossilized in silica rocks is studied by cw-EPR, ENDOR, HYSCORE, and DFT calculations. It is well-known that porphyrins, which are common to all living organisms, form vanadyl−porphyrin complexes in sediments deposited in oceans. However, the stability of these complexes over a very long time (more than 3 billion years) is not known. By encapsulating vanadyl−porphyrin complexes in silica synthesized by a sol−gel method to mimic SiO2 sediments, we studied the structure and stability of these complexes upon step heating treatments by monitoring the evolution of the g factor and of the hyperfine interactions with 51V, 1H, 14N, 13C, and 29Si nuclei. It is found that vanadyl−porphyrin complexes are progressively transformed into oxygenated vanadyl complexes by transfer of the VO2+ ion from the porphyrin ring to the mineral matrix. The organic component is transformed into carbonaceous matter which contains paramagnetic centers (IOM• centers). To test the validity of this approach, we studied by EPR a 3490 million years old chert (polycrystalline SiO2 rock) containing some of the oldest putative traces of life. This rock contains oxygenated vanadyl complexes and IOM• centers very similar to those found in the synthetic analogues.Lire moins >
Lire la suite >The possibility of using vanadyl ions as paramagnetic biomarkers for the identification of traces of primitive life fossilized in silica rocks is studied by cw-EPR, ENDOR, HYSCORE, and DFT calculations. It is well-known that porphyrins, which are common to all living organisms, form vanadyl−porphyrin complexes in sediments deposited in oceans. However, the stability of these complexes over a very long time (more than 3 billion years) is not known. By encapsulating vanadyl−porphyrin complexes in silica synthesized by a sol−gel method to mimic SiO2 sediments, we studied the structure and stability of these complexes upon step heating treatments by monitoring the evolution of the g factor and of the hyperfine interactions with 51V, 1H, 14N, 13C, and 29Si nuclei. It is found that vanadyl−porphyrin complexes are progressively transformed into oxygenated vanadyl complexes by transfer of the VO2+ ion from the porphyrin ring to the mineral matrix. The organic component is transformed into carbonaceous matter which contains paramagnetic centers (IOM• centers). To test the validity of this approach, we studied by EPR a 3490 million years old chert (polycrystalline SiO2 rock) containing some of the oldest putative traces of life. This rock contains oxygenated vanadyl complexes and IOM• centers very similar to those found in the synthetic analogues.Lire moins >
Langue :
Anglais
Comité de lecture :
Oui
Audience :
Internationale
Vulgarisation :
Non
Établissement(s) :
Université de Lille
CNRS
CNRS
Collections :
Date de dépôt :
2021-06-18T08:21:26Z
2021-10-14T08:26:47Z
2021-10-14T08:26:47Z