Stable free imino and nitronyl nitroxyl radicals of the acetylene series: synthesis, electronic absorption spectra and magnetic resonance parameters

Methods for the synthesis of aryl(hetaryl)ethynylphenyl-2-imidazoline nitroxides have been developed; the g-tensor and HFI components for imidazoline-1-oxyl were found to depend (in contrast to imidazoline-3-oxide-1-oxy derivatives) on the properties of substituent at the 2-position.