Electron spin density distribution of a series of nitroxide radicals with five-member ring as studied by solid-state 1H, 2H and 13C NMR

Stable nitroxide radicals are useful to construct molecular magnetic systems. Particularly, radicals substituted by –COOH and –CONH2 can be coordinated to magnetic metal ions and may be used as cladding reagents of gold nano-particles for modifying magnetism. Nitroxide molecules with unsaturated five-member ring have almost planner structure and electron spin delocalization may be expected. We determined the hyperfine coupling constants (hfcc) of 1H, 2H and 13C of a series of nitroxide radicals with five-member ring. Experimental values of hfcc were compared with those deduced from calculations based on density functional theory. The electron spin density distribution at β position of ring was sensitive to the ring structure, although the electron spin density at β position is small compared with N–O site. Magnetic susceptibility and UV–Vis absorption spectra were also measured and discussed.

Graphical abstractHyperfine coupling constants (hfcc) of 1H, 2H and 13C of a series of nitroxide radicals with five-member ring were determined by solid-state magic angle spinning 1H, 2H and 13C NMR. Experimental values of hfcc were compared with those deduced from calculations based on density functional theory. Magnetic susceptibility and UV–Vis absorption spectra were also measured and discussed.Figure optionsDownload full-size imageDownload as PowerPoint slide