Synthesis, structure and magnetic properties of lanthanide(III) complexes with new imidazole-substituted imino nitroxide radical

New lanthanide-radical complexes, [LnIII(hfac)3(IM2imH)] (Ln = Gd, Tb; IM2imH = 2-(2-pyridyl)-4,5-dihydro-4,4,5,5-tetramethyl-1H-imidazolyl-1-oxy), were prepared and characterized by the X-ray structural analysis and magnetic susceptibility measurement. The polyhedron of [Tb(hfac)3(IM2imH)] is close to SAPR-8. There is found to be a weak antiferromagnetic interaction between Gd(III) and IM2imH in [Gd(hfac)3(IM2imH)], which is examined in connection with planarity of the IM2imH chelate.