Dynamic nuclear polarization in highly fluorinated solutions


Ovalioglu H., PEKSÖZ A., ENGİN KIRIMLI H., Yalciner A.

Journal of Dispersion Science and Technology, vol.31, no.3, pp.332-337, 2010 (Peer-Reviewed Journal) identifier identifier

  • Publication Type: Article / Article
  • Volume: 31 Issue: 3
  • Publication Date: 2010
  • Doi Number: 10.1080/01932690903192572
  • Journal Name: Journal of Dispersion Science and Technology
  • Journal Indexes: Science Citation Index Expanded, Scopus
  • Page Numbers: pp.332-337
  • Keywords: Dynamic nuclear polarization, Epr spectra, Fluorine-electron double resonance, Free radical, Overhauser effect

Abstract

The Overhauser effect type dynamic nuclear polarization experiments were performed to study solutions of the stable free radical a,c-Bisdiphenylene-b-phenyl allyl complex with benzene (1:1) in some highly fluorinated aliphatic and aromatic solvents. In solutions examined in this study, it occurs mainly the Overhauser effect, which normally arises due to both dipolar and scalar interactions between the unpaired electrons of the free radical molecules and fluorine nuclei of solvent molecules. 1-Iodotridecafluorohexane, N-Methyl-bis-trifluoroacetamide, Octafluoroto- luene and Hexafluorobenzene were used as the solvents. The experiments were performed at a low field double resonance NMR spectrometer, which operates at 1.53 mT. The NMR enhancements depend on competition between intermolecular magnetic interactions. It was studied to investigate variation of EPR spectra with four different temperatures. It was found as temperature increases, peak points of EPR spectra decreases. © Taylor & Francis Group, LLC.