A Series of High-Nuclear Gadolinium Cluster Aggregates with a Magnetocaloric Effect Constructed through Two-Component Manipulation

Abstract

The serialized expansion of high-nuclear clusters usually includes the controlled variable method and changes only a single variable. However, changing both variables will greatly increase the complexity of the reaction simultaneously. Therefore, the use of a two-component regulation reaction is rare. Herein, we used a diacylhydrazone ligand (H 4 L 1 ) with multidentate chelating coordination sites for the reaction with Gd(NO 3 ) 3 •6H 2 O under solvothermal conditions to obtain an example of 16-nucleus discshaped cluster 1 with a brucite structure. The overall structure of cluster 1 can be regarded as an equilateral triangle, which is formed by three (L 1 ) 4− ions that can be regarded as "sides" and wrap the four-layer metal center Gd(III) ions. Notably, upon simultaneous regulation of the substituent of the ligand and the coordination anion, heptanuclear gadolinium cluster 2 was obtained. Cluster 2 can be regarded as a butterfly structure, which was formed by connecting two Gd 3 L 2 molecules that were not in the same plane and through the central Gd(III) ion as an intersection. Moreover, hexanuclear gadolinium cluster 3 was obtained by changing the ligand substituent and adding an auxiliary ligand. Cluster 3 can be regarded as a chair structure, which was composed of two molecules of diacylhydrazone ligand (L 2 ) 4− wrapping vacant cubane shared by four vertices. This study was the first to construct a series of high-nuclear gadolinium clusters through two-component regulation manipulation. The study of the magnetocaloric effect showed that the maximum values of −ΔS m for clusters 1−3 were 34.05, 29.04, and 24.32 J kg −1 K −1 , respectively, when T = 2 K and ΔH = 7 T.

Giant Crown-Shaped Dy34 Nanocluster with High Acid–Base Stability Assembled by an out-to-in Growth Mechanism

“…In 2020, the authors’ group obtained an example of a double cage-like dysprosium cluster Dy 60 by reacting a polydentate chelate-coordinated bisacylhydrazone ligand with Dy­(OAc) 3 ·4H 2 O under solvothermal conditions . Although tremendous progress has been made, the design and synthesis of high-nucleation lanthanoid clusters with specific shapes and linkages are still stagnant and currently limited to common shapes, such as cages, tubes, and wheels. − The main reasons are the large radius of lanthanoid metal ions, complex coordination modes, difficulty in forming stable coordination bonds with metal ions, difficulty in controlling the hydrolysis process, diverse hydrolysis products, and self-assembly processes interfered by multiple templates. , Therefore, designing and synthesizing high-nucleation lanthanoid clusters with special shapes are still extremely difficult, and the progress is slow. , …”

Coordination site manipulation of the annular growth mechanism to assemble chiral lanthanide clusters with different shapes and magnetic properties

“…[25][26][27] Although the exploration of the self-assembly mechanism of lanthanide clusters is still at the initial stage, we have made a series of progresses in this field. [28][29][30][31][32][33][34][35][36][37] In 2018, we were the first to use HRESI-MS to track the self-assembly process of triangular-shaped dysprosium clusters with toroidal magnetic moments. 28 Furthermore, we were the first to use crystallography combined with the HRESI-MS technique to trace the formation mechanism of the high-nuclearity lanthanide cluster Dy 10 with double relaxation behavior.…”

Anion-Manipulated Hydrolysis Process Assembles of Giant High-Nucleation Lanthanide-Oxo Cluster

“…High-nucleation lanthanide clusters with unique shapes, attractive structures, and superior characteristics are actively continuously being designed and synthesized. − To date, different lanthanide clusters with various shapes, linkages, and nuclei have been prepared, and their applications in the fields of molecular magnetism, luminescence, sensing, and catalysis have been successfully expanded. − Although great progress has been made, high-nucleation lanthanide cluster design and synthesis have also been aided by a number of assembly methods. − In 2021, our group first proposed an out-to-in growth mechanism for designing and synthesizing a series of discoid lanthanide clusters . Afterward, we found that the outside-in growth mechanism can be effectively manipulated by regulating the reaction solvent or anion or by adding a second ligand, and we obtained a series of lanthanide clusters with different shapes. , However, the out-to-in growth mechanism is only suitable for bulky organic ligands that have strong chelating ability and numerous coordination sites. − When the organic ligands in the reaction system have small volumes, poor chelating ability, and few coordination sites, the hydrolysis conditions and anionic template become a major factor in controlling the formation of lanthanide clusters. ,,− Ligand-mediated hydrolysis of lanthanide ions first undergoes tight binding between Ln­(III) ions and water to obtain hydrolysis products with various shapes (template precursors), such as linear {Ln 2 (μ 2 -OH)}, triangular {Ln 3 (μ 3 -OH)}/{Ln 3 (μ 3 -OH) 2 }, tetrahedral {Ln 4 (μ 3 -OH) 4 }, trigonal bipyramidal {Ln 5 (μ 3 -OH) 6 }, square pyramidal {Ln 5 (μ 3 -OH) 4 (μ 4 -O)}, and octahedral {Ln 6 (μ 3 -OH) 8 (μ 6 -O)}. ,, The hydrolysates are then captured by ligands for assembly to form lanthanide clusters with specific shapes. Therefore, manipulating lanthanide-ion hydrolysis to produce certain template motifs with specific assembly is an effective strategy for constructing lanthanide clusters with specific shapes and linkages .…”