Manipulating Solvothermal Coordination-Catalyzed In Situ 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 4 (L 1 ) 2 (L 2 ) 2 (OAc) 4 ]·4C 2 H 5 OH·3H 2 O ( 1 , L 1 = 1,3,4-thiadiazole-2,5-diamine, H 4 L 2 = 6,6'-(((1,3,4-thiadiazole-2,5-diyl)bis(azanediyl))bis(((3-ethoxy-2-hydroxybenzyl)oxy)methylene))bis(2-ethoxyphen), [Dy 4 (L 3 ) 4 (OAc) 4 ]·C 2 H 5 OH·H 2 O ( 2 , H 3 L 3 = 2-(((5-amino-1,3,4-thiadiazol-2-yl)amino)((3-ethoxy-2-hydroxybenzyl)oxy)methyl)-6-ethoxyphenol)), [Dy 6 (L 4 ) 4 (L 5 ) 2 (μ 3 -OH) 4 (CH 3 O) 4 Cl 4 ]Cl 2 ( 3 , H 2 L 4 = 2-hydroxy-3-methoxybenzaldehyde, H 2 L 5 = 2-(((5-amino-1,3,4-thiadiazol-2-yl)amino)(hydroxy)methyl)-6-methoxyphenol), and [Dy 6 (L 6 ) 4 (L 7 ) 2 (μ 3 -OH) 4 (CH 3 O) 4 Cl 4 ]Cl 2 ·2H 3 O ( 4 , H 2 L 6 = 2-hydroxy-3-ethoxybenzaldehyde, H 2 L 7 = 2-(((5-amino-1,3,4-thiadiazol-2-yl)amino)(hydroxy)methyl)-6-ethoxyphenol). A series of acetal products (H 4 L 2 , H 3 L 3 , H 2 L 5 , and H 2 L 7 ) were obtained through dehydration in situ tandem reactions. Magnetic studies show that complexes 1 - 4 exhibited different single-molecule magnet behavior under zero-field conditions. The best fitting results showed that under zero DC field, the effective energy barriers ( U eff ) and magnetic relaxation times (τ 0 ) of complexes 1 - 4 are U eff = 117.0 (2.1) K and τ 0 = 6.07 × 10 -7 s; U eff = 83.91 (1.5) K and τ 0 = 4.28 × 10 -7 s; U eff = 1.28 (0.2) K and τ 0 = 0.73 s, and U eff = 104.43 (13.3) K and τ 0 = 8.25 × 10 -8 s, respectively.