Anion‐Templated Assembly and Magnetocaloric Properties of a Nanoscale {Gd₃₈} Cage versus a {Gd₄₈} Barrel

Abstract

The comprehensive study reported herein provides compelling evidence that anion templates are the main driving force in the formation of two novel nanoscale lanthanide hydroxide clusters, {Gd38(ClO4)6} (1) and {Gd48Cl2(NO3)} (2), characterized by single-crystal X-ray crystallography, infrared spectroscopy, and magnetic measurements. {Gd38(ClO4)6}, encapsulating six ClO4(-) ions, features a cage core composed of twelve vertex-sharing {Gd4} tetrahedrons and one Gd⋅⋅⋅Gd pillar. When Cl(-) and NO3(-) were incorporated in the reaction instead of ClO4(-), {Gd48Cl2(NO3)} is obtained with a barrel shape constituted by twelve vertex-sharing {Gd4} tetrahedrons and six {Gd5} pyramids. What is more, the cage-like {Gd38} can be dynamically converted into the barrel-shaped {Gd48} upon Cl(-) and NO3(-) stimulus. To our knowledge, it is the first time that the linear M-O-M' fashion and the unique μ8-ClO4(-) mode have been crystallized in pure lanthanide complex, and complex 2 represents the largest gadolinium cluster. Both of the complexes display large magnetocaloric effect in units of J kg(-1) K(-1) and mJ cm(-3) K(-1) on account of the weak antiferromagnetic exchange, the high N(Gd)/M(W) ratio (magnetic density), and the relatively compact crystal lattice (mass density).

A brilliant cryogenic magnetic coolant: magnetic and magnetocaloric study of ferromagnetically coupled GdF3

“…2-3 At an early stage, the cryogenic magnetic coolants are mainly the inorganic paramagnetic salts and oxides, such as Gd 2 (SO 4 ) 3 ·8H 2 O and Gd 3 Ga 5 O 12 (GGG). 4 In recent years, molecular materials suddenly emerged in this field as an unprecedented classification, and a lot of highly competitive molecular magnetic coolants of 3d, [5][6][7][8][9][10][11] 3d-4f 12-21 and 4f-types [22][23][24][25][26][27][28][29] have been synthesized and characterized. Their distinct advantages, such as stoichiometric composition, monodispersity and modifiability, have provided the researchers a perfect platform to realize the design strategies towards cryogenic magnetic coolants.…”

Magnetic Properties of 3D Heptanuclear Lanthanide Frameworks Supported by Mixed Ligands

“…4 As a result, a lot of pure lanthanide clusters, such as Ln 3 −Ln 10 , 5 Ln 12 −Ln 15 , 6 Ln 20 , 7 Ln 22 , 8 Ln 24 , 9 Ln 36 , 10 Ln 38 11 Ln 48 , 11,12 Ln 60 , 13 and Ln 104 , 14 have been documented. Recently, Yaghi et al proposed that metal cluster units may self-assemble into coordination polymers, 15 which will bring about the particular characteristics of the clusters into the obtained frameworks.…”

Large Magnetocaloric Effect in a Dense and Stable Inorganic–Organic Hybrid Cobridged by In Situ Generated Sulfate and Oxalate

“…[8] Compared with the discrete complexes, the main superiority of polymeric complexes is that the adjacent metal ions or metal clusters share the bridging ligands among them, which can prompt the magnetic density and generate a large MCE. [3e,f] However, to date, most of the known Gd-containing complexes with a remarkable MCE from 0D clusters to 3D architectures are fabricated via organic ligands, [5, 6] and cases constructed by inorganic ligands are sparse.[8c,h,j] Actually, some inorganic ligands like sulfate, phosphate, and carbonate are also polydentate. For example, the tetradentate sulfate with diverse binding modes could readily bond to lanthanide ions, which has been broadly used to prepare metalorganic frameworks (MOFs).…”

“…[2] Since observations of MCE in Mn 12 and Fe 8 molecular clusters, molecule-based magnetic refrigerants have been a focus of research and are developing rapidly due to their synthetic tunability and functional tailorability. [3][4][5][6][7][8] To design desirable magnetocaloric molecules, Gd 3 + is a good candidate because its intrinsic nature, such as large spin ground state S, D ion = 0, and low-lying excited spin states, satisfies to improve the performance in MCE. [4] Moreover, owing to the shielding characteristic of the 4f orbitals of Gd 3 + , the magnetic couplings of Gd 3 + -Gd 3 + /3d-Gd 3 + are usually expected to be weak, which is also beneficial to enhance the MCE.…”