http://www.arkat-usa.org/get-file/37461/

High resolution NMR of free radicals: 13C magic angle spinning of two solid organic free radicals derived from 4,5-dihydro-1H-imidazol-3-oxide-1-oxyl and theoretical calculation of their NMR properties

The 13C CPMAS NMR spectra of  two 4,4,5,5-tetramethyl-2-(1H- and 2H-pyrazol-3-yl)-2-imidazoline-1-oxyl-3-oxides have been recorded and their signals assigned, through unrestricted density functional theory (UDFT) calculations of their absolute shieldings, with satisfactory results.