Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa 920-1192, Japan.
Nano Life Science Institute, Kanazawa University, Kanazawa 920-1192, Japan.
Proc Natl Acad Sci U S A. 2022 Mar 15;119(11):e2113237119. doi: 10.1073/pnas.2113237119. Epub 2022 Mar 8.
SignificanceWe first observed a transient chirality inversion on a simple unimolecular platform during the racemization of a chiral helical complex [LCo], i.e., the helicity changed from -rich (right-handed) to -rich (left-handed), which then racemized to a / equimolar mixture in spite of the absence of a reagent that could induce the helix. This transient chirality inversion was observed only in the forward reaction, whereas the reverse reaction showed a simple monotonic change with an induction time. Consequently, the helicity appeared only in the forward reaction. These forward and reverse reactions constitute a hysteretic cycle. Compounds showing such unique time responses would be useful for developing time-programmable switchable materials that can control the physical/chemical properties in a time-dependent manner.
意义 我们首次在一个简单的单分子平台上观察到手性螺旋配合物 [LCo]消旋过程中出现的短暂手性反转，即螺旋结构从富（右）手性转变为富（左）手性，尽管没有可以诱导螺旋结构的试剂存在，但该配合物最终仍消旋为等量的混合物。这种短暂的手性反转仅在正向反应中观察到，而反向反应则表现出简单的单调变化，并伴随着诱导时间。因此，只有在正向反应中才会出现螺旋结构。这些正向和反向反应构成了一个滞后循环。具有这种独特时间响应的化合物将有助于开发时间可编程的开关材料，这些材料可以在时间相关的方式下控制物理/化学性质。
