The Photostability of Two Optical Materials Based on Perylene Diimide Substituted by Different Aromatic Groups at the Bay Area

The perylene diimide substituented by thiophene rings at bay area shows photoactivity and can be used as a photo sensor, but another one substituented by mestylene groups is photostable. The single crystal of 1,7‐mesitylene perylene diimide was obtained. X‐ray diffraction data of the crystal revealed that the plane of the perylene core was hardly twisted by introduction of mesitylene groups. These mestylene groups are like clips maintaining the planarity of the perylene core. Density functional theory calculation was applied to study the difference of photophysical and photochemical properties. The discovery is valuable for design guidance of perylene diimides.