Sato Osamu
Special Research Laboratory for Optical Science, Kanagawa Academy of Science and Technology, KSP Building East 412, 3-2-1 Sakado, Takatsu-ku, Kawasaki-shi, Kanagawa 213-0012, Japan.
Acc Chem Res. 2003 Sep;36(9):692-700. doi: 10.1021/ar020242z.
A possible route to finding new optically switchable molecular solids is to investigate the photoeffects of compounds that exhibit an abrupt phase transition or hysteresis loop. Such compounds must possess at least bistable states that are separated by a potential barrier in free energy. In fact, on the basis of this idea, we have recently succeeded in identifying three kinds of optically switchable molecular compounds. These include an Fe(III) spin-crossover complex exhibiting light induced excited spin state trapping effects and a Cu(II) photochromic complex and an FeCo Prussian blue exhibiting photoinduced magnetization. It should be noted that abrupt phase transitions or phase transitions with a hysteresis loop are observed when cooperativity due to an intermolecular interaction operates within the crystals. This suggests that the introduction of intermolecular interactions such as pi-pi interactions, hydrogen bonding, or an ion-dipole interaction might serve to achieve optical switching effects in molecular compounds.
寻找新型光可切换分子固体的一种可能途径是研究那些表现出突变相变或滞后回线的化合物的光效应。这类化合物必须至少拥有两个由自由能势垒分隔的双稳态。事实上，基于这一理念，我们最近成功鉴定出了三种光可切换分子化合物。其中包括一种表现出光诱导激发自旋态俘获效应的Fe(III)自旋交叉配合物、一种Cu(II)光致变色配合物以及一种表现出光致磁化的FeCo普鲁士蓝。应当指出的是，当晶体内部因分子间相互作用产生协同效应时，会观察到突变相变或具有滞后回线的相变。这表明引入诸如π-π相互作用、氢键或离子-偶极相互作用等分子间相互作用，可能有助于在分子化合物中实现光开关效应。
