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

Abstract

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 [Dy4(L1)2(L2)2(OAc)4]·4C2H5OH·3H2O (1, L1 = 1,3,4-thiadiazole-2,5-diamine, H4L2 = 6,6′-(((1,3,4-thiadiazole-2,5-diyl)bis(azanediyl))bis(((3-ethoxy-2-hydroxybenzyl)oxy)methylene))bis(2-ethoxyphen), [Dy4(L3)4(OAc)4]·C2H5OH·H2O (2, H3L3 = 2-(((5-amino-1,3,4-thiadiazol-2-yl)amino)((3-ethoxy-2-hydroxybenzyl)oxy)methyl)-6-ethoxyphenol)), [Dy6(L4)4(L5)2(μ3–OH)4(CH3O)4Cl4]Cl2 (3, H2L4 = 2-hydroxy-3-methoxybenzaldehyde, H2L5 = 2-(((5-amino-1,3,4-thiadiazol-2-yl)amino)(hydroxy)methyl)-6-methoxyphenol), and [Dy6(L6)4(L7)2(μ3–OH)4(CH3O)4Cl4]Cl2·2H3O (4, H2L6 = 2-hydroxy-3-ethoxybenzaldehyde, H2L7 = 2-(((5-amino-1,3,4-thiadiazol-2-yl)amino)(hydroxy)methyl)-6-ethoxyphenol). A series of acetal products (H4L2, H3L3, H2L5, and H2L7) 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 (τ0) of complexes 1–4 are U eff = 117.0 (2.1) K and τ0 = 6.07 × 10–7 s; U eff = 83.91 (1.5) K and τ0 = 4.28 × 10–7 s; U eff = 1.28 (0.2) K and τ0 = 0.73 s, and U eff = 104.43 (13.3) K and τ0 = 8.25 × 10–8 s, respectively.

Different anion (NO3− and OAc−)-controlled construction of dysprosium clusters with different shapes

“…This decreasing χ m T value with temperature may be caused by the gradually decreasing Stark level of the excited state of the thermally reduced Dy( iii ) ion and/or the crystal field effect. 63,64 Furthermore, there is a weak increase in the χ m T of cluster 4 in the high temperature region. As the temperature decreases, the maximum value of 36.23 is reached at 89 K. Finally, it exhibits a decreasing trend in the low temperature area and reaches a minimum value of 23.9 cm 3 K mol −1 at 2 K. In summary, cluster 4 exhibits weak antiferromagnetic interactions.…”

Two Octa-Nuclear {Ln8} (Ln = Tb, Dy) Complexes with “4 + 4” Covalent Organic Macrocycles: Structure, Solution Behavior, Luminescence, and Magnetic Properties

“…As the temperature drops from 300 to 22 K, the value of χ m T of Dy 8 L 4+4 gradually decreases, from 22 to 2 K, the value of χ m T slightly increases. The rise of the χ m T value of Dy 8 L 4+4 in the low-temperature region was generally considered suggestive of ferromagnetic interaction between the Dy centers. , …”

“…The rise of the χ m T value of Dy 8 L 4+4 in the low-temperature region was generally considered suggestive of ferromagnetic interaction between the Dy centers. 38,39 The field-dependent magnetizations of Dy 8 L 4+4 were tested at different temperatures (2.0 and 5.0K) (Figure S9b). Their measured magnetization at a temperature of 2 K increases rapidly in the low-field region and gradually flattens out in the high-field region.…”

“One-Pot” In Situ Tandem Reaction─Dy(III) Coordination-Catalyzed Multicomponent Condensation of Salicylaldehyde Derivatives to Obtain Ketals

“…In recent years, high-resolution electrospray mass spectrometry (HRESI-MS) has been widely used to study the mechanism of coordination-catalyzed in situ tandem reactions. ,, In order to deeply explore the reaction mechanism of the formation of dimer (I/II) and trimer (I/II), the species changes in the reaction solution were tracked by time-dependent HRESI-MS, and the possible formation mechanism of dimers and trimers was speculated (Figures and ). At 0 min (stirred at room temperature for 5 min), 30 min, 3 h, 6 h, 12 h, 24 h, and 48 h, the reaction solution was taken out immediately and diluted in chromatographic methanol for HRESI-MS test.…”