Wang Jin-Jin, Li Yu, Zheng Teng-Fei, Peng Yan, Chen Jing-Lin, Liu Sui-Jun, Wen He-Rui
School of Chemistry and Chemical Engineering, Jiangxi Provincial Key Laboratory of Functional Molecular Materials Chemistry, Jiangxi University of Science and Technology, Ganzhou 341000, Jiangxi Province, P.R. China.
Dalton Trans. 2024 Mar 19;53(12):5601-5607. doi: 10.1039/d3dt03867j.
The design and synthesis of a Gd(III) metal-organic framework with the formula [Gd(BTDI)(DMF)] (JXUST-40, HBTDI = 5,5'-(benzo[][1,2,5]thiadiazole-4,7-diyl)diisophthalic acid) are reported hererin. Interestingly, a reversible single-crystal-to-single-crystal transition between JXUST-40 and {[Gd(BTDI)(HO)]·6HO} (JXUST-40a) was achieved under the stimulation of heat and solvents. Both JXUST-40 and JXUST-40a exhibited good stability when soaked in common solvents and aqueous solutions with pH values of 1-12. Magnetic studies showed that JXUST-40a has a larger magnetocaloric effect with -Δmaxm = 26.65 J kg K at 2 K and 7 T than JXUST-40 due to its larger magnetic density. Structural analyses indicated that the coordinated solvent molecules play a crucial role in the coordination environment around the Gd(III) ions and the change in the framework, ultimately leading to the changes in the pore size and magnetism between JXUST-40 and JXUST-40a. In addition, both isomorphic [Dy(BTDI)(DMF)] (JXUST-41) and {[Dy(BTDI)(HO)]·6HO} (JXUST-41a) displayed slow magnetic relaxation behaviour.
本文报道了一种化学式为[Gd(BTDI)(DMF)]（JXUST - 40，HBTDI = 5,5'-(苯并[][1,2,5]噻二唑 - 4,7 - 二基)二间苯二甲酸）的钆（III）金属有机框架的设计与合成。有趣的是，在热和溶剂的刺激下，JXUST - 40与{[Gd(BTDI)(HO)]·6HO}（JXUST - 40a）之间实现了可逆的单晶到单晶转变。当浸泡在pH值为1 - 12的常见溶剂和水溶液中时，JXUST - 40和JXUST - 40a均表现出良好的稳定性。磁性研究表明，由于其更大的磁密度，JXUST - 40a在2 K和7 T时具有比JXUST - 40更大的磁热效应，-Δmaxm = 26.65 J kg K。结构分析表明，配位溶剂分子在钆（III）离子周围的配位环境和框架变化中起关键作用，最终导致JXUST - 40和JXUST - 40a之间孔径和磁性的变化。此外，同构的[Dy(BTDI)(DMF)]（JXUST - 41）和{[Dy(BTDI)(HO)]·6HO}（JXUST - 41a）均表现出缓慢的磁弛豫行为。
