Two Discrete Ln₁₂ Shelf‐Shaped Clusters: Magnetic Studies Reveal a Significant Cryogenic Magnetocaloric Effect and Slow Magnetic Relaxation

Abstract

Two unique dodecanuclear lanthanide clusters, [Ln III 12 Na 3 (μ 3 -OH) 2 (hmmp) 6 (piv) 12 (CO 3 ) 6 (MeOH) 6 ]OH·5MeOH {Ln = Gd 3+ , Dy 3+ ; hmmpH 2 = 2-[(2-hydroxyethylimino)methyl]-6-methoxyphenol}, have been synthesized by treating the simple Schiff-base ligand hmmpH 2 with the relevant lanthanide chloride and sodium pivalate (NaPiv). Single-crystal X-ray diffraction analysis revealed that the central cores of Gd 12 and Dy 12 are unprecedented and composed of a distorted four-layer [a]

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

“…The most interesting structural characteristic of the Dy 12 nanocluster is that two different kinds of chair construction Dy 6 rings can be observed and an overall particular “double-chair” conformation was obtained. Interestingly, no μ 3 -bridged oxygen atoms and triangular or cubane-like subclusters can be observed in the “double-chair” type clusters, which were commonly seen in the reported Ln 12 clusters as mentioned above. − Figures S1 and S2 show the packed structures of the Dy 12 along the a -direction and c -direction, respectively.…”

“…Wang et al recently reported two homometallic Ln 12 clusters with the formula of [Ln 12 (H 2 L1) 4 (μ 3 -O) 4 (μ 3 -OH) 4 (CH 3 COO) 15 ]·(CH 3 COO)·(CH 3 OH) 6 (Ln = Dy (1) and Gd (2)) using 2,6-bis­(2-(( E )-2-hydroxybenzylidene)­hydrazine-1-carbonyl) pyridine 1-oxide (H 4 L1) ligand and Ln­(CH 3 COO) 3 ·6H 2 O. In these homometallic dodecanuclear clusters, the main core of [Ln 12 (μ 3 -OH) 4 (μ 3 -O) 4 (μ 2 -O) 14 ] can be divided into four triangular [Ln 3 (μ 3 -O)­(μ 2 -O) 3 ] with three Ln III ions under the connection of oxygen bridges, which were integrated by a vertex-sharing cubic [Ln 4 (μ 3 -O) 4 ] 4– cluster. − …”

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

“…Based on the above study, it has been found that appropriate multidentate ligands can link and stabilize lanthanide ions to make their self-assembly regular, which is instrumental for the framework expansion of Ln-exclusive clusters. ,− As a remarkable sort of multifunctional bridging ligand, HIN is a linear ligand with the −COOH group and the N atom on opposite sides, which benefits the construction of exquisite and multidimensional lanthanide-organic frameworks . Concerning the anionic template approach, a small volume of anions is regarded as a reaction building block to disperse the highly positive charge of hydroxyl intermediates, such as the shelf-shaped cluster Ln 12 templated by a single-anion template (CO 3 2– ) and the cage-like Ln 27 clusters templated by mixed-anion templates (CO 3 2– and ClO 4 – ). , Among anion templates, HCOO – , as a light and short anionic template, is exactly embedded in the cavity of the cationic cluster to disperse the highly positive charges …”

“…Nanosized lanthanide clusters, as a peculiar category of molecules, exhibit captivating structural multiformities and own unique chemical and physical properties, which are potentially applied in the fields of catalysts, molecular electronics, optics, magnetocaloric effect (MCE), etc . − Over the past few decades, a variety of Ln-exclusive clusters have been further reported, such as Ln 5 , Ln 10 , Ln 12 , Ln 18 , Ln 20 , Ln 24 , Ln 27 , Ln 36 , Ln 37 , Ln 38 , Ln 48 , Ln 60 , Ln 104 , and Ln 140 . − Most of the high-nuclearity Ln-exclusive nanoclusters reported so far are cage-shaped or ring-shaped, and the exquisite windmill-shaped configuration has not been reported yet. On the other hand, despite significant advances in the synthesis and the framework expansion of Ln-exclusive clusters, constructing novel multidimensional high-nuclearity lanthanide nanoclusters with giant MCEs is still a big challenge, given the fact that the hydrophobic ligands within the fringe of the cluster cores hinder any extended lanthanide-organic frameworks. − …”

Hierarchical Coordination Frameworks Based on Metal–Organic Dimeric Nanocapsules Comprising Praseodymium and Pyrogallol[4]arene

“…Synthesizing nanocapsules with lanthanide ions has not been fully explored. , Lanthanide ions have been widely used as a functional constituent in coordination polymers, , sensors, , molecular magnets, − magnetic refrigerants, − and catalysts. − In this study, we report the synthesis of a praseodymium­(III)-seamed dimeric nanocapsule and hierarchical coordination frameworks (1D and 3D) formed from linking the individual nanocapsule SBBs. To date, there has only been a single example of a molecular cage based on praseodymium­(III) bonded to calix[4]­pyrrole dibenzoic acid and a nanocontainer capsule based on [(Mo)­Mo 5 O 21 (H 2 O) 6 ] 12 [Mo 2 O 4 (SO 4 )] 30 hosting praseodymium­(III) atoms in the tunnels …”