Magnetic relaxation in mononuclear Tb complex involving a nitronyl nitroxide ligand

Abstract

Two new lanthanide complexes with nitronyl nitroxide radicals [Ln(hfac)₃(NIT-C₃H₅)(H₂O)] (Ln^III = Gd 1, Tb 2; NIT-C₃H₅ = 2-cyclopropyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) have been synthesized. The two complexes possess a mononuclear structure in which the nitronyl nitroxide radical is coordinated to a Ln ion as a monodentate ligand through the NO group. Magnetic studies show that the lanthanide ion interacts ferromagnetically with the nitronyl nitroxide radical. Moreover, ac measurements show that the Tb complex exhibits frequency-dependent out-of-phase signals suggesting single-molecule magnet behavior.