Hagiwara Hiroaki, Hashimoto Shingo, Matsumoto Naohide, Iijima Seiichiro
Department of Chemistry, Faculty of Science, Kumamoto University, Kurokami 2-39-1, Kumamoto 860-8555, Japan.
Inorg Chem. 2007 Apr 16;46(8):3136-43. doi: 10.1021/ic061960a. Epub 2007 Mar 16.
A 2D iron(II) spin crossover complex, FeII(HLH,Me)22.1.5MeCN (1), was synthesized, where HLH,Me = imidazol-4-yl-methylidene-8-amino-2-methylquinoline. 1 showed a gradual spin transition between the HS (S = 2) and LS (S = 0) states from 180 to 325 K within the first warming run from 5 to 350 K, in which 1.5MeCN is removed, and there was an abrupt spin transition at T1/2 downward arrow = 174 K in the first cooling run from 350 to 5 K. Following the first cycle, the compound showed an abrupt spin transition at T1/2 upward arrow = 185 K and T1/2 downward arrow = 174 K with 11 K wide hysteresis in the second cycle. The crystal structures of 1 were determined at 296 (an intermediate between the HS and LS states) and 150 K (LS state). The structure consists of a 2D extended structure constructed of both the bifurcated NH...O- hydrogen bonds between two ClO4- ions and two neighboring imidazole NH groups of the [FeII(HLH,Me)2]2+ cations and the pi-pi interactions between the two quinolyl rings of the two adjacent cations. Thermogravimetric analysis showed that solvent molecules are gradually eliminated even at room temperature and completely removed at 369 K. Desolvated complex 1' showed an abrupt spin transition at T1/2 upward arrow = 180 K and T1/2 downward arrow = 174 K with 6 K wide hysteresis.
合成了一种二维铁（II）自旋交叉配合物FeII(HLH,Me)22·1.5MeCN（1），其中HLH,Me = 咪唑-4-基亚甲基-8-氨基-2-甲基喹啉。在从5到350 K的首次升温过程中，1在180至325 K之间显示出从高自旋（S = 2）态到低自旋（S = 0）态的逐渐自旋转变，在此过程中1.5MeCN被去除，并且在从350到5 K的首次冷却过程中，在T1/2向下箭头 = 174 K处出现突然的自旋转变。在第一个循环之后，该化合物在第二个循环中在T1/2向上箭头 = 185 K和T1/2向下箭头 = 174 K处显示出突然的自旋转变，具有11 K宽的滞后现象。在296 K（高自旋和低自旋态之间的中间态）和150 K（低自旋态）下测定了1的晶体结构。该结构由二维扩展结构组成，该结构由两个ClO4-离子与[FeII(HLH,Me)2]2+阳离子的两个相邻咪唑NH基团之间的分叉NH...O-氢键以及两个相邻阳离子的两个喹啉环之间的π-π相互作用构成。热重分析表明，即使在室温下溶剂分子也会逐渐被去除，并在369 K时完全去除。去溶剂化的配合物1'在T1/2向上箭头 = 180 K和T1/2向下箭头 = 174 K处显示出突然的自旋转变，具有6 K宽的滞后现象。
