Lehn Jean-Marie
Institut de Science et d'Ingénierie Supramoléculaires, Université Louis Pasteur, 8 Allée Gaspard Monge, 67000 Strasbourg, France.
Chemistry. 2006 Aug 7;12(23):5910-5. doi: 10.1002/chem.200600489.
Compounds containing the C==N group, such as imines and their derivatives, may undergo syn-anti isomerization by two different routes: 1) photochemically, by out-of-plane rotation around the carbon-nitrogen double bond through a "perpendicular" form, and 2) thermally, by in-plane nitrogen inversion through a "linear" transition state. When the two interconversions occur in sequence, a full, closed process is accomplished, restoring the initial state of the system along two different steps. In a chiral imine-type compound, for example, with an asymmetric center next to the C==N function, photoinduced rotation may be expected to occur in one sense in preference to the opposite one. Thus, photoisomerization followed by thermal isomerization in a chiral imine compound generates unidirectional molecular motion. Generally, imine-type compounds represent unidirectional molecular photomotors converting light energy into mechanical motion. As they are also able to undergo exchange of the carbonyl and amine partners, they present constitutional dynamics. Thus, imine-type compounds are double dynamic, motional, and constitutional devices.
含有C==N基团的化合物，如亚胺及其衍生物，可通过两种不同途径进行顺反异构化：1）光化学途径，即通过围绕碳氮双键的平面外旋转形成“垂直”形式；2）热途径，即通过平面内氮反转形成“线性”过渡态。当这两种相互转化依次发生时，就完成了一个完整的闭环过程，沿着两个不同步骤恢复系统的初始状态。例如，在手性亚胺型化合物中，在C==N官能团旁边有一个不对称中心，光诱导旋转可能会优先以一种方向而非相反方向发生。因此，在手性亚胺化合物中，光异构化后接着热异构化会产生单向分子运动。一般来说，亚胺型化合物代表将光能转化为机械运动的单向分子光马达。由于它们还能够进行羰基和胺配体的交换，所以呈现出结构动力学。因此，亚胺型化合物是具有双重动态性、运动性和结构变化的装置。
