Title :

Biradical character of D-rich carriers in the insoluble organic matter of carbonaceous chondrites: A relic of the protoplanetary disk chemistry

Author(s) :

Delpoux, Olivier [Auteur]
Laboratoire de Chimie de la Matière Condensée de Paris (site ENSCP) [LCMCP (site ENSCP)]
Gourier, Didier [Auteur]
Laboratoire de Chimie de la Matière Condensée de Paris (site ENSCP) [LCMCP (site ENSCP)]
Vezin, Herve [Auteur]
Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement (LASIRE) - UMR 8516
Binet, Laurent [Auteur]
Laboratoire de Chimie de la Matière Condensée de Paris (site ENSCP) [LCMCP (site ENSCP)]
Derenne, Sylvie [Auteur]
Institut d'écologie et des sciences de l'environnement de Paris [iEES]
Robert, François [Auteur]
Laboratoire de Minéralogie et Cosmochimie du Muséum [LMCM]

Journal title :

Geochimica et Cosmochimica Acta

Abbreviated title :

Geochimica et Cosmochimica Acta

Volume number :

75

Pages :

326-336

Publisher :

Elsevier BV

Publication date :

2011-01-01

ISSN :

0016-7037

HAL domain(s) :

Chimie/Chimie théorique et/ou physique
Chimie/Matériaux

English abstract : [en]

The insoluble organic matter (IOM) of the Orgueil meteorite contains deuterium-rich radicals detectable by Electron Paramagnetic Resonance (EPR) techniques (Gourier et al., 2008). However the structure of these deuterium ...
Show more >The insoluble organic matter (IOM) of the Orgueil meteorite contains deuterium-rich radicals detectable by Electron Paramagnetic Resonance (EPR) techniques (Gourier et al., 2008). However the structure of these deuterium carriers remains poorly constrained. In this work, their electronic structure is deduced from the measurement of the spin states S by transient nutation in pulsed-EPR. It is shown that these deuterium-rich radicals are dominated by biradicaloids (species with S = 0 ground state and thermally accessible S = 1 state) and biradicals (species with S = 1 ground state) representing ∼61% and ∼31% of the radicals in the IOM of Orgueil, respectively, while single radicals (S = 1/2) contribute only to ∼8%. This is definitely different from mature terrestrial IOMs, which are known to contain almost exclusively S = 1/2 radicals. A structural model is proposed, whereby the occurrence of dominant biradicaloids and biradicals is the direct consequence of the structure of the IOM, made of a network of small aromatic moieties linked by branched and short aliphatic units. This implies that the formation of stable biradicaloids and biradicals by C–H breaking and their deuterium enrichment are produced after the formation of the IOM in the primitive solar system. These results reinforce the idea that the formation of the IOM and the deuterium-rich hotspots are the product of ion chemistry in the solar disk.Show less >

Language :

Anglais

Audience :

Internationale

Popular science :

Non

Administrative institution(s) :

Université de Lille
CNRS

Collections :

• Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement (LASIRE) - UMR 8516

Submission date :

2021-06-18T08:05:09Z
2021-10-08T11:54:47Z