On the Transition from a Biomimetic Molecular Switch to a Rotary Molecular Motor

yThe 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 lightdriven 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 timeresolved 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.

Automated summary

An experimental/computational study of a candidate obtained via the asymmetrization of a light-driven biomimetic molecular switch was conducted. The achieved motor has an ECD band that is remarkably sensitive to isomerization motion, suitable for timeresolved ECD studies. However, the synthesized motor isomerizes on a longer time scale than expected.