Ligand Induced Double-Chair Conformation Ln₁₂ Nanoclusters Showing Multifunctional Magnetic and Proton Conductive Properties

Abstract

Many methods have been utilized to adjust the size of superatomic metal nanoclusters, while tuning the geometric conformations of specific nanoclusters is rare. Here, we demonstrate that conformation variation can be realized by slightly modifying the ligand under maintaining the nuclei number of metal atoms. A series of novel “double-chair” conformation Ln12 (Ln = Sm (1), Eu (2), Gd (3), Tb (4), and Dy (5)) clusters were generated by replacing 3-formylsalicylic acid with 2,3-dihydroxybenzoic acid in the Ln12 nanocluster. Intriguingly, Dy12 displays slow magnetic relaxation at low temperatures, while Gd12 shows a large magnetocaloric effect (MCE) of 35.63 J kg–1 K–1 at 2 K for ΔH = 7 T. Additionally, the introduction of numerous coordination water molecules in these clusters enables Dy12 and Gd12 with high proton conductivity, namely, 2.13 × 10–4 and 3.62 × 10–4 S cm–1 under 358 K and 95% RH humidity conditions.

Two Windmill-Shaped Ln18 Nanoclusters Exhibiting High Magnetocaloric Effect and Luminescence

“…How to assemble discrete clusters into exquisite structures and multidimensional nanoclusters appears to be the key point to the development of metal–organic frameworks. To the best of our knowledge, there are two time-honored synthetic methods, namely, ligand-controlled hydrolysis and anionic templates. , In the ligand-controlled hydrolytic approach, lanthanide ions are primitively combined with water and allowed to further react in hydrolysis to obtain Ln-hydroxyl intermediates, such as octahedral {Ln 6 (μ 6 -O)­(μ 3 -OH) 8 }, trigonal bipyramidal {Ln 5 (μ 3 -OH) 6 }, tetrahedral {Ln 4 (μ 3 -OH) 4 }, and trigonal {Ln 3 (μ 3 -OH) 2 } units. , In 2013, one high-nuclearity nanocluster Ho 48 , showing a two-dimensional layer, was synthesized in the presence of isonicotinic acid (HIN) by our group, which was assembled by tetrahedral {Ho 4 (μ 3 -OH) 4 } and square pyramids {Ho 5 (μ 3 -OH) 4 (μ 5 -O)} units . In 2017, a hexagram-shaped Er 18 cluster with six vertex-sharing {Er 4 (μ 3 -OH) 4 } intermediates was constructed by controlling the hydrolysis of lanthanide ions via 2,2-dimethylolpropionic acid .…”

“…To the best of our knowledge, there are two time-honored synthetic methods, namely, ligand-controlled hydrolysis and anionic templates. 24,25 In the ligand-controlled hydrolytic approach, lanthanide ions are primitively combined with water and allowed to further react in hydrolysis to obtain Ln-hydroxyl intermediates, such as octahedral {Ln 6 (μ 6 -O)(μ 3 -OH) 8 }, trigonal bipyramidal {Ln 5 (μ 3 -OH) 6 }, tetrahedral {Ln 4 (μ 3 -OH) 4 }, and trigonal {Ln 3 (μ 3 -OH) 2 } units. 26,27 In 2013, one high-nuclearity nanocluster Ho 48 , showing a two-dimensional layer, was synthesized in the presence of isonicotinic acid (HIN) by our group, which was assembled by tetrahedral {Ho 4 (μ 3 -OH) 4 } and square pyramids {Ho 5 (μ 3 -OH) 4 (μ 5 -O)} units.…”

C2O42−-templated cage-shaped Ln28(Ln = Gd, Eu) nanoclusters with magnetocaloric effect and luminescence

“…[13][14][15] At the same time, aesthetically captivating configurations with various conformations and shapes have been designed, such as chair, boat, cage, disk, wheel, nanocapsule, etc. [16][17][18][19][20][21] However, due to practical obstacles in their sizeable ionic radius and high coordination numbers, as well as the mutual repulsion between lanthanide ions, the assembly of highnuclearity lanthanide nanoclusters is a great challenge, especially when the number of the lanthanide ions is greater than 20. 15,22,23 It is well known that in situ reactions can benefit the formation of anionic templates through decomposition, rearrangement and other unpredictable side reactions of solvents or ligands.…”

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.…”