Département de chimie physique, Université de Genève, 30 Quai Ernest-Anserment, 1211 Genève 4, Switzerland.
Chemistry. 2013 Aug 19;19(34):11418-28. doi: 10.1002/chem.201301257. Epub 2013 Jul 12.
Whereas the neat polymeric Fe(II) compound {[Fe(bbtr)3 ][ClO4 ]2 }∞ (bbtr=1,4-di(1,2,3-triazol-1-yl)butane) shows an abrupt spin transition centered at 107 K facilitated by a crystallographic symmetry breaking, in the covalently linked 2D coordination network of {[Fe(bbtr)3 ][BF4 ]2 }∞ , Fe(II) stays in the high-spin state down to 10 K. However, strong cooperative effects of elastic origin result in reversible, persistent, and wavelength-selective photoswitching between the low-spin and high-spin manifolds. This compound thus shows true light-induced bistability below 100 K. The persistent bidirectional optical switching behavior is discussed as a function of temperature, irradiation time, and intensity. Crystallographic studies reveal a photoinduced symmetry breaking and serve to establish the correlation between structure and cooperative effects. The static and kinetic behavior is explicated within the framework of the mean-field approximation.
虽然规整的聚合态 Fe(II) 化合物 {[Fe(bbtr)3 ][ClO4 ]2 }∞（bbtr=1,4-二(1,2,3-三氮唑-1-基)丁烷）在晶体对称性破缺的作用下，以 107 K 为中心发生急剧的自旋转变，但在共价连接的二维配位网络 {[Fe(bbtr)3 ][BF4 ]2 }∞中，Fe(II) 保持高自旋状态，直至 10 K。然而，弹性起源的强烈协同效应导致在低自旋和高自旋之间进行可逆、持久和波长选择性的光致开关。因此，该化合物在 100 K 以下表现出真正的光诱导双稳性。讨论了持久的双向光开关行为作为温度、辐照时间和强度的函数。晶体学研究揭示了光诱导的对称性破缺，并建立了结构与协同效应之间的相关性。静态和动力学行为在平均场近似的框架内得到了解释。
