Origin of the isotropic motion in crystalline molecular rotors with carbazole stators

摘要: Herein we report two crystalline molecular rotors 1 and 4 that show extremely narrow signals in deuterium solid-state NMR spectroscopy. Although this line shape is typically associated with fast-moving components, our VT 2H experiments, along X-ray diffraction analyses periodic DFT computations spectroscopic feature can also be originated from low-frequency intramolecular rotations of the central phenylene a cone angle 54.7° attained by cooperative motion entire structure distorts axis to rotation. In contrast, isomeric structures (2 3) do not noticeable rotation, because their crystallographic arrays showed very restricting close contacts. Our findings clearly indicate multiple components phase transitions machines work concert achieve desired motion.