Anisotropic bending and twisting behaviour of a twin crystal composed of a diarylethene

Here, we found that crystals consisting of 1,2-bis(2-methyl-5-(4-undecyloxyphenyl)-3-thienyl)-perfluorocyclopentene (1a) exhibit unusual photomechanical bending. Upon irradiation with ultraviolet (UV) light, the crystal bent toward the incident light, but the velocity of the bending depended on the illumination directions. When irradiated from the left and right sides of the crystal, the velocities of the bending were different from each other. We found that the crystal is a twin crystal, as confirmed by X-ray crystallography. The bending mechanism of the twin crystal can be interpreted from the content of twin components, the absorption anisotropy of diarylethene molecules and the degree of the crystal twisting.

Automated summary

The crystals formed by 1,2-bis(2-methyl-5-(4-undecyloxyphenyl)-3-thienyl)-perfluorocyclopentene demonstrated unique photomechanical bending behavior under UV light irradiation, with bending velocity depending on lighting directions. This crystal was identified as a twin crystal through X-ray crystallography, and the bending mechanism was found to be influenced by twin components, absorption anisotropy of diarylethene molecules, and crystal twisting degree.