title: A high saturation factor in Overhauser DNP with nitroxide derivatives: the role of (14)N nuclear spin relaxation.
abstract: Overhauser DNP enhancements of toluene were measured at a magnetic field of 0.35 Tesla in a series of chemically functionalized nitroxide radicals. We observe that the enhancements increase systematically with polarizer size and rotational correlation time. Examination of the saturation factor of (14)N nitroxides by pulsed ELDOR spectroscopy led to a quantitative interpretation of the enhancements, for which the saturation factor increases up to almost unity due to enhanced nuclear ((14)N) relaxation in the nitroxide radical. The observation has a direct impact on the choice of optimum DNP polarizers in liquids.
authors: RG EPR spectroscopy, Max-Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany.
authors: Nikolay
authors: N
authors: Enkin
authors: Guoquan
authors: G
authors: Liu
authors: Maria Del Carmen
authors: Mdel C
authors: Gimenez-Lopez
authors: Kyriakos
authors: K
authors: Porfyrakis
authors: Igor
authors: I
authors: Tkach
authors: Marina
authors: M
authors: Bennati
mesh_terms: D005609:Free Radicals / Q000737:chemistry; D037741:Fullerenes / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D009584:Nitrogen / Q000737:chemistry*; D009589:Nitrogen Oxides / Q000737:chemistry*
chemical_list: D005609:Free Radicals; D037741:Fullerenes; D009589:Nitrogen Oxides; D009584:Nitrogen