title: Room-temperature switching of magnetic hysteresis by reversible single-crystal-to-single-crystal solvent exchange in imidazole-inspired Fe(ii) complexes.
abstract: The recent upsurge in molecular magnetism reflects its application in the areas of sensors and molecular switches. Thermal hysteresis is crucial to the molecular bistability and information storage, a wide hysteresis near room temperature is expected to be of practical sense for the molecular compound. In this work, spin crossover iron(ii) complexes [Fe(Liq)2](BF4)2·(CH3CH2)2O (1-Et2O) and [Fe(Liq)2](BF4)2·3H2O (1-3H2O) were prepared and structurally and magnetically analysed. The single-crystal-to-single-crystal (SCSC) solvation transformation and the influence on the crystal structures and magnetic hysteresis were investigated in an etherification-hydration cycle. At room temperature, X-ray diffraction experiments indicated a transformation from one crystal (1-Et2O, P21212) to another crystal (1-3H2O, P212121) upon humidity exposure and reversible recovery of its crystallinity upon exposure to ether vapor. The etherified phase 1-Et2O exhibits room temperature spin crossover (T1/2 = 305 K) but negligible thermal hysteresis, however the hydrated phase 1-3H2O exhibits the apparent hysteresis loop (T1/2↑ = 346 K, T1/2↓ = 326 K) which expands to room temperature. This effect is associated with the change of intermolecular cooperativity in the etherification-hydration recyclability.
authors.affiliation: Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, Collaborative Innovation Center of Advanced Catalysis & Green Manufacturing, School of Petrochemical Engineering, Changzhou University, Changzhou, Jiangsu 213164, China. wudy@cczu.edu.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Huang
authors.forename: Fuxing
authors.initials: F
authors.lastname: Shen
authors.forename: Ming
authors.initials: M
authors.lastname: Zhang
authors.forename: Dayu
authors.initials: D
authors.lastname: Wu
authors.forename: Feifei
authors.initials: F
authors.lastname: Pan
authors.forename: Osamu
authors.initials: O
authors.lastname: Sato