Synthesis, structures and magnetic properties of three cyclic lanthanide complexes with nitronyl nitroxide radical

Abstract

Three new lanthanide complexes based on a nitronyl nitroxide radical [Ln(hfac)3(NIT3Ph3Py)]2 (Ln = Dy(1), Tb(2), Gd(3); hfac = hexafluoroacetylacetonate, NIT3Ph3Py = 2-(3′-(3″-pyridyl)-phenyl)-4,4,5,5- tetramethylimidazoline-1-oxyl-3-oxide) have been successfully synthesized, characterized structurally and magnetically. Single crystal X-ray diffraction analysis reveals that complexes 1–3 are isomorphous in which NIT3Ph3Py acts as a bridging ligand linking two Ln(III) ions through the nitrogen atom of pyridine ring and the oxygen atom of NO group to form a four-spin system. The magnetic studies reveal that the ferromagnetic interactions between the Ln(III) ions and nitronyl nitroxide radicals in the complexes. Moreover, alternating current (ac) magnetic susceptibilities show that Dy(III) complex exhibits frequency-dependent signals at low temperature.