Widespread concern has been raised over the synthesis of highly nucleated lanthanide clusters with special shapes and/or specific linkages. Construction of lanthanide clusters with specific shapes and/or linkages can be achieved by carefully regulating the hydrolysis of lanthanide metal ions and the resulting hydrolysis products. However, studies on the manipulation of lanthanide-ion hydrolysis to obtain giant lanthanide-oxo clusters have been few. In this study, we obtained a tetraicosa lanthanide cluster (3) by manipulating the hydrolysis of Dy(III) ions using an anion (OAc − ). As far as we know, cluster 3 has the highest nucleation among all lanthanide-oxo clusters reported. In 3, two triangular Dy 3 O 4 are oriented in opposite directions to form the central connecting axis Dy 6 (OH) 8 , which is in turn connected to six Dy 3 O 4 that are oriented in different directions. Meanwhile, a sample of a chiral trinuclear dysprosium cluster (1) was obtained in a mixed CH 3 OH and CH 3 CN solvent and by replacing the anion in the reaction to Cl − ions. In this cluster, 1,3,4thiadiazole-2,5-diamine (L 2 ) is free on one side through π•••π interactions and is parallel to the o-vanillin (L 1 ) − ligand, thus resulting in a triangular arrangement. The arrangement of L 2 affects the end group coordination in the cluster 1 structure through hydrogen bonding and induces the cluster to exhibit chirality. When the reaction solvent was changed to CH 3 OH, a sample of cluster 2, composed of two independent triangular Dy 3 that have different end group arrangements, was obtained. Magnetic analysis showed that clusters 1 and 3 both exhibit distinctive single-molecule magnetic properties under zero-magnetic-field conditions. This study thus provides a method for the creation of chiral high-nucleation clusters from achiral ligands and potentially paves the way for the synthesis of high-nucleation lanthanide clusters with unique forms.

Two Dy4 complexes, namely, [Dy4(L 1 )4(NO3)2(μ3-OH)2]­·2C2H5OH­·3H2O (1) and [Dy4(L 2 )4(NO3)2(μ3-OH)2]­·3C2H5OH­·8H2O (2), were successfully designed and synthesized under solvothermal conditions. X-ray diffraction results show that both of them display unique {Dy4O8} cores, and the four central Dy­(III) ions are arranged in a regular rhombic frame coplane. Surprisingly, 1 and 2 with a similar structure show the same metal ion coordination environment, but the topological stacking mode has changed drastically due to the introduction of −CH3 into the ligand of 2. Complex 1 shows a fcu network topology with 10 connections, while 2 displays a bcu topology with 8 connections. In addition, magnetic studies revealed that both of them are single-molecular magnets with effective energy barriers of 79.22 and 67.61 K, respectively. Interestingly, complex 2 has undergone a transition from single relaxation of the zero field to two-step relaxation process of the optimal field. The discussion of the magnetic structure relationship in this work provides a good example for exploring the factors affecting magnetic relaxation dynamics.

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.

No abstract

There have been many examples of synthesizing multinuclear lanthanide clusters of special shapes, such as spherical, cage-shaped, tubular, and so on. However, synthesizing multinuclear lanthanide clusters with distinct layered structures possess a challenge. We use the ligands 2,3-dihydroxybenzaldehyde, benzohydrazide and pyridin-2-ylmethanamine to obtain a single layer of six-core lanthanide clusters [Dy 6 (μ 3 -O)(μ 3 -OH) 4 (L 2 ) 3 (L 3 ) 3 (L 4 ) 3 (H 2 O) 3 ]Cl 6 •CH 3 OH ( 1) and [Gd 6 (μ 3 -O)(μ 3 -OH) 4 (L 2 ) 3 (L 3 ) 3 (L 4 ) 3 (H 2 O) 2 (CH 3 OH)]Cl 6 •CH 3 OH•3CH 3 CN (2). The central metal ion of cluster 1 presents a triangular lattice shape. We changed the ligands to 2-hydroxy-3-methoxybenzaldehyde and 2-aminobenzoic acid and obtained the double-layer eightcore lanthanide clusters [Dy 8 (μ 3 -OH) 6 (L 5 ) 2 (L 6 ) 8 ] (3) and [Gd 8 (μ 3 -OH) 6 (L 5 ) 2 (L 6 ) 8 ]•4CH 3 OH•CH 3 CN (4). The upper and lower layers of cluster 3 have four metal ions, respectively, forming a huge cavity inside the structure. This is the first time that a multinuclear lanthanide cluster with a layered structure has been constructed by the in situ reaction of mixed ligands. AC susceptibility test shows that the imaginary part signals of cluster 1 do not show frequency dependence and the imaginary part signals of cluster 3 show frequency dependence at low temperatures. By fitting the Arrhenius equation, we obtain U eff = 2.87 K and τ 0 = 2.76 × 10 −4 s.