Dipartimento di Biotecnologie, Chimica e Farmacia, Università di Siena, Via A. Moro 2, 53100 Siena, Italy.
Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy.
J Phys Chem Lett. 2021 Apr 29;12(16):3875-3884. doi: 10.1021/acs.jpclett.1c00526. Epub 2021 Apr 15.
The experimental investigation of the unidirectional motion characterizing the photoisomerization of single-molecule rotary motors requires accessible lab prototypes featuring an electronic circular dichroism (ECD) signal that is sensitive to the geometrical and electronic changes occurring during an ultrafast reactive process. Here we report a combined experimental/computational study of a candidate obtained via the asymmetrization of a light-driven biomimetic molecular switch. We show that the achieved motor has an ECD band that is remarkably sensitive to the isomerization motion, and it is therefore suitable for time-resolved ECD studies. However, we also find that, unexpectedly, the synthesized motor isomerizes on a time scale longer than the subpicosecond time measured for the achiral parent, a result that points to alternative candidates conserving a high reaction speed.
单分子旋转马达光异构化的单向运动的实验研究需要可访问的实验室原型，其具有对超快反应过程中发生的几何和电子变化敏感的电子圆二色性（ECD）信号。在这里，我们报告了通过不对称光驱动仿生分子开关获得的候选物的组合实验/计算研究。我们表明，所获得的马达的 ECD 带对异构化运动非常敏感，因此适合于时间分辨的 ECD 研究。然而，我们也发现出乎意料的是，合成的马达的异构化时间比非手性母体测量的亚皮秒时间长得多，这一结果指向了保持高反应速度的替代候选物。
