Manipulating Solvothermal Coordination-Catalyzed Tandem Reactions to Construct Dysprosium-Based Complexes with Different Shapes and Zero-Field SMM Behaviors.

By changing the coordination anions (OAc and Cl), reaction temperature, solvent, and ligand substituents, four Dy(III)-based complexes were obtained by directed synthesis, which are [Dy(L)(L)(OAc)]·4CHOH·3HO (, L = 1,3,4-thiadiazole-2,5-diamine, HL = 6,6'-(((1,3,4-thiadiazole-2,5-diyl)bis(azanediyl))bis(((3-ethoxy-2-hydroxybenzyl)oxy)methylene))bis(2-ethoxyphen), [Dy(L)(OAc)]·CHOH·HO (, HL = 2-(((5-amino-1,3,4-thiadiazol-2-yl)amino)((3-ethoxy-2-hydroxybenzyl)oxy)methyl)-6-ethoxyphenol)), [Dy(L)(L)(μ-OH)(CHO)Cl]Cl (, HL = 2-hydroxy-3-methoxybenzaldehyde, HL = 2-(((5-amino-1,3,4-thiadiazol-2-yl)amino)(hydroxy)methyl)-6-methoxyphenol), and [Dy(L)(L)(μ-OH)(CHO)Cl]Cl·2HO (, HL = 2-hydroxy-3-ethoxybenzaldehyde, HL = 2-(((5-amino-1,3,4-thiadiazol-2-yl)amino)(hydroxy)methyl)-6-ethoxyphenol). A series of acetal products (HL, HL, HL, and HL) were obtained through dehydration tandem reactions. Magnetic studies show that complexes - exhibited different single-molecule magnet behavior under zero-field conditions. The best fitting results showed that under zero DC field, the effective energy barriers () and magnetic relaxation times (τ) of complexes - are = 117.0 (2.1) K and τ = 6.07 × 10 s; = 83.91 (1.5) K and τ = 4.28 × 10 s; = 1.28 (0.2) K and τ = 0.73 s, and = 104.43 (13.3) K and τ = 8.25 × 10 s, respectively.