A Dy4 single-molecule magnet and its Gd(III), Tb(III), Ho(III), and Er(III) analogues encapsulated by an 8-hydroxyquinoline Schiff base derivative and β-diketonate coligand
Five new tetranuclear complexes based on an 8-hydroxyquinoline Schiff base derivative and the β-diketone coligand, [Ln4(acac)4L6(μ3-OH)2]·CH3CN·0.5CH2Cl2 (Ln = Gd (1), Tb (2), Dy (3), Ho (4) and Er (5); HL = 5-(benzylidene)amino-8-hydroxyquinoline; acac = acetylacetonate) have been synthesized, and structurally and magnetically characterized. Complexes 1–5 have similar tetranuclear structures. Each LnIII ion is eight coordinated and its coordination polyhedra can be described as being in a distorted square-antiprismatic geometry. The magnetic studies reveal that 1 features the magnetocaloric effect (MCE) with the magnetic entropy change of −ΔSm(T) = 25.08 J kg−1 K−1 at 2 K for ΔH = 7 T, and 3 displays the slow magnetic relaxation behavior of Single Molecule Magnets (SMMs) with the anisotropic barrier of 86.20 K and the pre-exponential factor τ0 = 2.99 × 10−8 s.