Rare single-molecule magnets with six-coordinate Ln ions exhibiting a trigonal antiprism configuration

Four Ni-Ln-Ni heterometallic complexes, [Ni 2 LnL 2 ]NO 3 ·3H 2 O (H 3 L = tri(((3-methoxysalicylidene)amino)ethyl)amine, Ln = Gd for 1 , Tb for 2 and Dy for 3 , respectively) and [Ni 2 DyL 2 ]ClO 4 ·MTBE·0.65H 2 O ( 4 , MTBE = methyl tert -butyl ether) have been synthesized by diffusion of methyl tert -butyl ether vapor into the reaction solution. The X-ray analyses demonstrated that the Gd III ion in 1 exhibits rare seven-coordination, the Tb III and Dy III ions in 2-4 display unusual six-coordination, and two Ni II ions and one Ln III ion are bridged by six phenolato atoms to form linear Ni-Ln-Ni heterotrinuclear complexes for 1-4 . All complexes exhibit weak ferromagnetic interactions between Ni II and Ln III ions. Alternating current susceptibility measurements demonstrated that compounds 3 and 4 behave as single-molecule magnets with the effective energy barriers of 14.17 and 11.13 K under zero direct current field. They are rare single-molecule magnets containing six-coordinate Dy III ions. Four Ni-Ln-Ni heterometallic complexes containing seven- and six-coordinate Ln III ions have been obtained and structurally characterized. Magnetic studies show that Dy derivatives are rare single-molecule magnets containing six-coordinate Ln III ions.