Two Diamond-Shaped Dy₄ Complexes Caused by Different Topological Connections: Structure and Magnetism

Abstract

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.

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

“… , At room temperature, the χ m T values of clusters 1–3 were 33.51, 38.06, and 40.91 cm 3 K mol –1 , respectively, which were less than the theoretical values of three free Dy­(III) ions of 42.51 cm 3 K mol –1 ( 6 H 15/2 , S = 5/2, g = 4/3, L = 5, C = 14.17 cm 3 K mol –1 ) (Figure S6a,c,e). − The χ m T – T curves of clusters 1–3 were basically the same, and their χ m T values increased slightly with the decrease of temperature. Cluster 1 increased to 34.24 cm 3 K mol –1 at 139.86 K (Figure S6a), cluster 2 increased to 38.79 cm 3 K mol –1 at 89.97 K (Figure S6c), and cluster 3 increased to 42.03 cm 3 K mol –1 at 49.95 K (Figure S6e).…”

In Situ Reaction and Coordination Site Regulation to Form Binuclear Dysprosium Complexes with Different Connections and Magnetic Properties

“…The magnetic susceptibility of clusters 1 – 3 were tested at the temperature range of 300 to 2 K with an external magnetic field of 1000 Oe (Figure S6). ,, The results show that the χ m T values of complexes 1 and 3 at 300 K are 28.59 and 28.63 cm 3 ·K·mol –1 , respectively. Both of the values are close to the theoretical molar susceptibility of two uncoupled Dy­(III) ions ( S = 5/2, L = 5, g = 4/3).…”

“…Next, they obtained complexes with different relaxation behavior transitions by fine-tuning the coordination environment of the complexes . In 2019, our research group obtained two cases of tetranuclear dysprosium clusters with different SMM properties through substitution effect regulation . Acylhydrazone organic ligands with polydentate chelation sites can coordinate with metal ions through a variety of coordination methods. ,,− In particular, the pyridine-derived acylhydrazone ligands with easy adjustment and modification of coordination sites have opened up a new horizon for the study of the magneto-structural relationship of multinuclear lanthanide complexes …”

Bis-pyrazolone-based dysprosium(iii) complexes: zero-field single-molecule magnet behavior in the [2 × 2] grid DyIII4 cluster

“…10 As compared to mono-nuclear SMMs, there is a limited number of Ln-SMMs with higher nuclearity having a higher energy barrier (U eff ), where the {Dy 4 K 2 } compound has the highest U eff of 692 K. 20 The main reason could be due to the difficulty in manipulating the direction of the easy-axis arrangement and modulating the coordination geometry of the multiple spin centers owing to the LnIJIII) ions inherent nature, such as variable coordination sphere, their high coordination numbers and weak unpredictable stereochemical preferences. [21][22][23][24][25][26][27][28] Therefore, to further enhance the magnetic properties, it is of primary interest to understand their multi-nuclear LnIJIII)-based architectures, comprising their magneto-structural correlations between several spin carrier centers.…”