A family of lanthanide–nitronyl nitroxide complexes: syntheses, crystal structures and magnetic properties

Abstract

Seven Ln(III) complexes based on a novel nitronyl nitroxide radical have been synthesized and characterized structurally and magnetically: [Ln(hfac)₃(NITNapOMe)₂] (Ln = Pr(1), Gd(2), Tb(3), Dy(4), Ho(5), Er(6), Tm(7); hfac = hexafluoroacetylacetonate; NITNapOMe = 2-6′-methoxy-2′-naphthyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide). The single-crystal analyses show that these complexes have similar mononuclear tri-spin structures, in which central Ln(III) ions are eight coordinated by three hfac molecules and two NITNapOMe radicals. The variable-temperature magnetic susceptibility studies reveal the ferromagnetic interactions between Ln(III) ion and radicals in complexes 3, 4, and 7 and antiferromagnetic interactions in complexes 1, 2, 5, and 6.