Chameleonic layered metal–organic frameworks with variable charge-ordered states triggered by temperature and guest molecules. Issue 14 (17th March 2020)

• Record Type: Journal Article
• Authors: Chen, Jian; Sekine, Yoshihiro; Okazawa, Atsushi; Sato, Hiroyasu; Kosaka, Wataru; Miyasaka, Hitoshi
• Is Part Of: Chemical science. Volume 11:Issue 14(2020)
• Page Start: 3610
• Page End: 3618
• Publication Date: 2020-03-17
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d0sc00684j
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : A two-dimensional honeycomb layer composed of tetraoxolene-bridged iron subunits whose charge-ordered states are multiply variable via thermal treatments and solvation/desolvation is present. Abstract : Molecular materials whose electronic states are multiply varied depending on external stimuli are among the most promising targets for the development of multiply accessible molecular switches. Here, we report a honeycomb layer composed of tetraoxolene-bridged iron (Fe) subunits whose charge-ordered states are multiply variable via thermal treatments and solvation/desolvation with the crystallinity intact. The compound is (NPr4 )2 [Fe2 (Cl2 An)3 ] (1-d ; NPr4 + = tetra- n -propylammonium; Cl2 An 2− = 2, 5-dichloro-3, 6-dihydroxo-1, 4-benzoquinonate), which possesses three charge-ordered states: a low-temperature (LT) phase [(Fe 3+ )2 (Cl2 An 2− )(Cl2 An˙ 3− )2 ] 2− ; an intermediate (IM) phase [(Fe 2.5+ )2 (Cl2 An 2− )(Cl2 An 2.5− )2 ] 2− ; and a high-temperature (HT) phase [(Fe 2+ )2 (Cl2 An 2− )3 ] 2− that varies according to temperature. In addition, the LT phase of 1-d is reversibly changeable to another IM phase in its solvated compound 1 via a solvation/desolvation process at room temperature. This example demonstrates a new multiple-switching system based on electron transfer and host–guest chemistry in a charge-flexible metal–organic framework.