Flores Gonzalez Jessica, Montigaud Vincent, Dorcet Vincent, Bernot Kevin, Le Guennic Boris, Pointillart Fabrice, Cador Olivier
Univ Rennes, INSA Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, 35000, Rennes, France.
Institut Universitaire de France (IUF), 1 rue Descartes, F-75231, Paris, France.
Chemistry. 2021 Jul 12;27(39):10160-10168. doi: 10.1002/chem.202100953. Epub 2021 Jun 4.
Single-Molecule Magnet (SMM) property is by essence molecular, while commonly measured in solid crystalline state. Solvent crystallization molecules are usually neglected in the analysis and interpretation of solid-state properties. The solvation/desolvation process in the polyoxometalate(POM)-based Na [Er(W O ) ] ⋅ 35 H O SMM demonstrates that the dehydrated form relaxes more than 1000 times faster than the initial state, while the rehydration process allows the quasi complete recovering of the initial magnetic behaviour. This dehydration process is monitored by thermogravimetric analysis (TGA) and temperature-dependent X-ray powder diffraction, and rationalized by periodic quantum chemical calculations evidencing the tremendous role of the labile water molecules in the stability of the edifice. Ab-initio calculations highlight that sodium ions localization in the structure drive the magnetic responses. Isotopic enrichment with nuclear spin free ( Er, I=0) Er ions shows that the relaxation dynamics in the quantum regime depends on the nuclear spin.
单分子磁体（SMM）的性质本质上是分子层面的，而通常是在固体晶体状态下进行测量。在固态性质的分析和解释中，溶剂结晶分子通常被忽略。基于多金属氧酸盐（POM）的Na [Er（WO）]⋅35H₂O SMM中的溶剂化/去溶剂化过程表明，脱水形式的弛豫速度比初始状态快1000倍以上，而复水过程使初始磁行为几乎完全恢复。通过热重分析（TGA）和变温X射线粉末衍射监测该脱水过程，并通过周期性量子化学计算进行合理化，证明了不稳定水分子在结构稳定性中的巨大作用。从头算计算表明，结构中钠离子的定位驱动磁响应。用无核自旋的（¹⁵¹Er，I = 0）Er离子进行同位素富集表明，量子态下的弛豫动力学取决于核自旋。
