Díaz-Torres Raúl, Chastanet Guillaume, Collet Eric, Trzop Elzbieta, Harding Phimphaka, Harding David J
Thammasat University Research Unit in Multifunctional Crystalline Materials and Applications (TU-MCMA), Faculty of Science and Technology, Thammasat University Pathum Thani 12121 Thailand.
Université de Bordeaux, ICMCB 87 Avenue du Dr A. Schweitzer Pessac F-33608 France.
Chem Sci. 2023 Jun 1;14(26):7185-7191. doi: 10.1039/d3sc01495a. eCollection 2023 Jul 5.
The impact of solvent on spin crossover (SCO) behaviour is reported in two solvates [Fe(qsal-I)]NO·2ROH (qsal-I = 4-iodo-2-[(8-quinolylimino)methyl]phenolate; R = Me 1 or Et 2) which undergo abrupt and gradual SCO, respectively. A symmetry-breaking phase transition due to spin-state ordering from a [HS] to [HS-LS] state occurs at 210 K in 1, while = 250 K for the EtOH solvate, where complete SCO occurs. The MeOH solvate exhibits LIESST and -LIESST from the [HS-LS] state, revealing a hidden [LS] state. Moreover, photocrystallographic studies on 1 at 10 K reveal re-entrant photoinduced phase transitions to a high symmetry [HS] phase when irradiated at 980 nm or a high symmetry [LS] phase after irradiation at 660 nm. This study represents the first example of bidirectional photoswitchability and subsequent symmetry-breaking from a [HS-LS] state in an iron(iii) SCO material.
在两种溶剂化物[Fe(qsal-I)]NO·2ROH（qsal-I = 4-碘-2-[(8-喹啉基亚氨基)甲基]苯酚盐；R = 甲基 1 或 乙基 2）中报道了溶剂对自旋交叉（SCO）行为的影响，这两种溶剂化物分别经历突然和逐渐的 SCO。在 1 中，由于自旋态从[HS]到[HS-LS]状态的有序排列，在 210 K 时发生了对称性破缺的相变，而乙醇溶剂化物在 250 K 时发生完全的 SCO。甲醇溶剂化物从[HS-LS]状态表现出光激发电子转移诱导的自旋态捕获（LIESST）和反向光激发电子转移诱导的自旋态捕获（-LIESST），揭示了一个隐藏的[LS]状态。此外，在 10 K 下对 1 进行的光晶体学研究表明，当在 980 nm 处照射时，会发生重入光诱导相变到高对称的[HS]相，或者在 660 nm 处照射后转变为高对称的[LS]相。这项研究代表了铁（III）SCO 材料中双向光开关性以及随后从[HS-LS]状态发生对称性破缺的首个实例。
