Fig. 2: Concept for photochemical elucidation of very fast molecular motor rotations.
From: A photochemical method to evidence directional molecular motions
Indanone rotor and part of the benzothiophenone stator are colored purple and the biaryl moiety is depicted in dark red. a Macrocyclic setup 2 with locked atropisomers of the biaryl moiety (purple) restricting the motor (blue) motions to only one half-space with respect to the sulfoxide oxygen (grey half cycles I (solid arrows) and dashed grey half cycles II (dotted arrows)). Quantum yields Φ for all four photoisomerization (hv) directions can thus be measured individually (expected clockwise (cw) direction indicated by blue arrows, opposite counterclockwise (ccw) direction by orange arrows). b Comparison of quantum yields with the same non-macrocyclic molecular motor 3 (black arrows) allows evidencing its unidirectional motion.
