Modulation of magnetic relaxation behaviors via replacing coordinated solvents in a series of linear tetranuclear Dy4 complexes

Abstract

Four linear tetranuclear dysprosium compounds, [Dy₄(L)₂(dbm)₆(ROH)₂]·x(ROH) (ROH = MeOH, x = 3 (1); ROH = EtOH, x = 3 (2); ROH = n-PrOH, x = 1 (3); ROH = n-BuOH, x = 1 (4); H₃L = N′-(2,3-dihydroxybenzylidene)-2-(6-hydroxymethyl)-pyridine carboxylic acid hydrazide, Hdbm = 1,3-diphenyl-1,3-propanedione) were successfully assembled via controlling the reaction solvents in the synthesis process. Structural analysis reveals that these four compounds possess a similar linear Dy₄ core but with different solvents coordinated to the central Dy(III) sites (MeOH for 1, EtOH for 2, n-PrOH for 3 and n-BuOH for 4). Detailed magnetic investigation reveals that 1–4 display different magnetic relaxation behaviors with the energy barrier (ΔE/k_B) values of 53.58 K for 1, 1.23 K for 2, 1.11 K for 3 and 0.65 K for 4. This study highlights the important role of solvent effects in modulating the structures and magnetic properties of multinuclear Dy-based single-molecule magnets.