Two Ln₂NIT₃ Complexes Based on 1‑Methyl-5-benzotriazole Nitronyl Nitroxide Radical with Slow Magnetic Relaxation Behavior

Two heterospin complexes, namely, [Ln2(hfac)6(1-Me-5-BetrzNIT)3] (Ln = Tb(1), Dy(2); hfac=hexafluoroacetylacetone; 1-Me-5-BetrzNIT=2-{5-(1-methyl)-benzotriazolyl}-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide), have been successfully obtained based on a benzotriazole nitronyl nitroxide radical. Single-crystal X-ray diffraction studies reveal that the two complexes are isomorphous and both of them exhibit as binuclear units through the bridging ligand 1-Me-5-BetrzNIT with the μ2–η1:η1 coordination mode. The static and dynamic magnetic properties of the two complexes were characterized. Dynamic magnetic performance shows that complex 1 has no obvious frequency dependence. For complex 2, the frequency-dependent out-of-phase signals as well as the slow relaxation of magnetization under a zero dc field confirm the single-molecule magnet behavior