Three lanthanide–nitronyl nitroxide complexes: Syntheses, crystal structures and magnetic properties

• Three novel lanthanide–radical complexes
• Complexes 1, 2 and 3 are isomorphous.
• Ferromagnetic interactions between Ln–radical
• Tb complex shows the presence of frequency-dependent signals.

Three rare earth–nitronyl nitroxide radical complexes [Ln(hfac)3(NIT-1′-MeBzIm)] (Ln(III) = Gd 1, Tb 2, Dy 3; hfac = hexafluoroacetylacetonate; NIT-1′-MeBzIm = 2-{2′-[(l′-methyl)-benzimidazolyl]}-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) have been successfully prepared and structurally characterized. X-ray crystallographic analysis reveals that all the three complexes are isomorphous. The center lanthanide(III) ions are eight-coordinated to one NIT-1′-MeBzIm and three hexafluoroacetylacetonate ligands. The NIT-1′-MeBzIm acts as a bidentate ligand via its nitrogen atom of the imidazole ring and the oxygen atom of the N–O group. The magnetic properties of complexes 1, 2 and 3 were studied. All of them exhibit ferromagnetic interaction. AC magnetic susceptibility studies show that Tb complex displays frequency-dependent signals at low temperature suggesting that it behaves as SMM.

Three new lanthanide–radical complexes have been successfully prepared. The magnetic studies reveal that Tb complex shows the presence of frequency-dependent signals at low temperature suggesting that it behaves as SMM.Figure optionsDownload as PowerPoint slide