1. Highly proton-conducting lanthanide metal–organic frameworks featuring highly oxygenated ligands with slow magnetic relaxation or magnetocaloric effect.
- Author
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Yang, Shun-Yi, Zhang, Qian, Zhang, Yang-Lu, Tan, Tie-Shen, Zhu, Junlun, Yang, Xiaodong, Shi, Le, Yang, Jiong, and Shao, Dong
- Subjects
MAGNETOCALORIC effects ,SOLID state proton conductors ,MAGNETIC properties ,MAGNETIC relaxation ,X-ray crystallography ,MAGNETIC entropy ,RARE earth metals - Abstract
Two isoreticular lanthanide metal–organic frameworks (Ln-MOFs), {[Ln
2 (H2 O)6 (H2 dobdc)6 ·12H2 O}n (Ln = Tb3+ and Gd3+ ); H4 dobdc = 2,5-di-hydroxy-benzene-1,4-di-carboxylic acid), constructed from a hydroxy-functionalized dicarboxybenzene were synthesized and structurally characterized. Single-crystal X-ray crystallography reveals that the two Ln-MOFs were constructed from Ln3+ dimers as secondary building units, which were linked by H2 dobdc2− ligands to form three-dimensional (3D) frameworks featuring pcu topology. Interestingly, 1D triangular porous channels were formed in the frameworks with a high density of coordinated and guest water molecules and hydroxy-containing inwall, which provide a hydrophilic and highly oxygenated environment. Magnetic studies indicated the Tb(III) analogue exhibited slow relaxation of magnetization under an applied static field of 2 kOe while the Gd(III) MOF displayed the magnetocaloric effect (MCE) with a magnetic entropy change of 19.5 J kg−1 K−1 . At 55 °C under 98% RH, impedance spectroscopy indicated that the Ln-MOFs exhibit high proton conductivities up to 1.63 × 10−2 and 2.51 × 10−2 S cm−1 through the vehicle mechanism, suggesting that the two are highly proton-conducting Ln-MOFs. This work not only demonstrates two rare magnetic-electrical bifunctional Ln-MOFs with high proton-conduction and interesting magnetic properties but also provides potential design guidelines for high-performance Ln-MOF based proton conductors. [ABSTRACT FROM AUTHOR]- Published
- 2024
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