ESR investigation of chemical exchange in geminally diphosphorylated linear nitroxide radicals

A. Rockenbauer, Gilles Olive, Xavier Rozanska, Alain Jacques, Didier Gigmes, François Le Moigne, Daniel Peeters, Anton German, Paul Tordo

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

For geminally diphosphorylated linear nitroxide radicals, a marked line width alternation (LWA) can be observed. The LWA appears irrespectively whether the investigated radicals R″N(Ȯ)C(P(O)(OEt) 2)2R″ contain any chiral group or not. If R″ = tert-butyl and R″ = H, the small β-hydrogen coupling indicates a completely blocked rotation around the N-C σ-bond and the LWA can be assigned to a chemical exchange between conformations in which the phosphoryl groups have a symmetric and a nonsymmetric geometry. The conformational change is accompanied by the deformation of the CP2 bonding angle and the rate of exchange is slowed in pentane for which the solvent molecules can be trapped by the chelating phosphoryl groups. If R″ = benzyl, both the proton hyperfine lines of the CH2 group and the phosphorus lines of the CP2 group produce a LWA; two coalescences can be observed. In the case of a chiral R″ group (R″ = secondary butyl, R″ = methyl) a tentative four-site model can explain the highly complex LWA.

Original languageEnglish
Pages (from-to)5484-5489
Number of pages6
JournalJournal of Physical Chemistry A
Volume108
Issue number25
DOIs
Publication statusPublished - Jun 24 2004

Fingerprint

Linewidth
alternations
Paramagnetic resonance
Chelation
Coalescence
pentanes
Phosphorus
Conformations
Protons
Hydrogen
coalescing
phosphorus
nitroxyl
Molecules
Geometry
protons
hydrogen
geometry
molecules

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

Cite this

ESR investigation of chemical exchange in geminally diphosphorylated linear nitroxide radicals. / Rockenbauer, A.; Olive, Gilles; Rozanska, Xavier; Jacques, Alain; Gigmes, Didier; Le Moigne, François; Peeters, Daniel; German, Anton; Tordo, Paul.

In: Journal of Physical Chemistry A, Vol. 108, No. 25, 24.06.2004, p. 5484-5489.

Research output: Contribution to journalArticle

Rockenbauer, A, Olive, G, Rozanska, X, Jacques, A, Gigmes, D, Le Moigne, F, Peeters, D, German, A & Tordo, P 2004, 'ESR investigation of chemical exchange in geminally diphosphorylated linear nitroxide radicals', Journal of Physical Chemistry A, vol. 108, no. 25, pp. 5484-5489. https://doi.org/10.1021/jp048652n
Rockenbauer, A. ; Olive, Gilles ; Rozanska, Xavier ; Jacques, Alain ; Gigmes, Didier ; Le Moigne, François ; Peeters, Daniel ; German, Anton ; Tordo, Paul. / ESR investigation of chemical exchange in geminally diphosphorylated linear nitroxide radicals. In: Journal of Physical Chemistry A. 2004 ; Vol. 108, No. 25. pp. 5484-5489.
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