Next Article in Journal
Comparison of Flavonoid Compounds in the Flavedo and Juice of Two Pummelo Cultivars (Citrus grandis L. Osbeck) from Different Cultivation Regions in China
Next Article in Special Issue
Thermal Reactivity of Neutral and Oxidized Ferrocenyl-Substituted Enediynes
Previous Article in Journal
Radical Intermediates in Photoinduced Reactions on TiO2 (An EPR Spin Trapping Study)
Previous Article in Special Issue
New Developments in Spin Labels for Pulsed Dipolar EPR
Article Menu

Export Article

Open AccessArticle
Molecules 2014, 19(11), 17305-17313; doi:10.3390/molecules191117305

The Dynamical Behavior of the s-Trioxane Radical Cation—A Low-Temperature EPR and Theoretical Study

1
Ingenieurgesellschaft Auto und Verkehr (IAV GmbH), Rockwellstraße 16, Gifhorn D-38518, Germany
2
Leibniz-Institute for Surface Modification, Permoserstraße 15, Leipzig D-04318, Gemany
3
Department of Physics, University of Leipzig, Linnéstraße 5, Leipzig D-04103, Gemany
These authors contributed equally to this work.
*
Author to whom correspondence should be addressed.
Received: 1 September 2014 / Revised: 15 October 2014 / Accepted: 21 October 2014 / Published: 28 October 2014
(This article belongs to the Special Issue Free Radicals and Radical Ions)
View Full-Text   |   Download PDF [1647 KB, uploaded 28 October 2014]   |  

Abstract

The radical cation of s-trioxane, radiolytically generated in a freon (CF3CCl3) matrix, was studied in the 10–140 K temperature region. Reversible changes of the EPR spectra were observed, arising from both ring puckering and ring inversion through the molecular plane. The ESREXN program based on the Liouville density matrix equation, allowing the treatment of dynamical exchange, has been used to analyze the experimental results. Two limiting conformer structures of the s-trioxane radical cation were taken into account, namely “rigid” half-boat and averaged planar ones, differing strongly in their electron distribution. The spectrum due to the “rigid” half-boat conformer can be observed only at very low (<60 K) temperatures, when the exchange of conformers is very slow. Two transition states for interconversion by puckering and ring-inversion were identified, close in activation energy (2.3 and 3.0 kJ/mol calculated). Since the energy difference is very small, both processes set on at a comparable temperature. In the case of nearly complete equilibration (fast exchange) between six energetically equivalent structures at T > 120 K in CF3CCl3, a septet due to six equivalent protons (hfs splitting constant 5.9 mT) is observed, characteristic of the dynamically averaged planar geometry of the radical cation. DFT quantum chemical calculations and spectral simulation including intramolecular dynamical exchange support the interpretation. View Full-Text
Keywords: radical cations; s-trioxane; EPR; DFT; dynamical exchange radical cations; s-trioxane; EPR; DFT; dynamical exchange
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

Scifeed alert for new publications

Never miss any articles matching your research from any publisher
  • Get alerts for new papers matching your research
  • Find out the new papers from selected authors
  • Updated daily for 49'000+ journals and 6000+ publishers
  • Define your Scifeed now

SciFeed Share & Cite This Article

MDPI and ACS Style

Naumov, S.S.; Knolle, W.; Naumov, S.P.; Pöppl, A.; Janovský, I. The Dynamical Behavior of the s-Trioxane Radical Cation—A Low-Temperature EPR and Theoretical Study. Molecules 2014, 19, 17305-17313.

Show more citation formats Show less citations formats

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]

Molecules EISSN 1420-3049 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top