Electronic Modulation of Terrylene Diimides Leading to Core-Twisting, Tunable Emission and Intermolecular Interactions

Three new symmetrically para‐phenylethynylene‐substituted terrylene diimide derivatives namely, TDI‐Ph, TDI‐PhCN and TDI‐PhNMe2 were synthesized to study the electronic effects on the structure and properties. The solid‐state single‐crystal structures for TDI‐Ph and TDI‐PhCN as well as for the precursor TDI‐Br4 are presented. The X‐ray diffraction studies revealed twisting in the bay‐area of terrylene core, which improved the solubility as well, despite of having some of the shortest intermolecular Br···Br and C‐H···O interactions in TDI‐Br4. All the compounds exhibited near infra‐red absorption and emission except for TDI‐PhNMe2; especially TDI‐PhNMe2 showed interesting broad absorption ranging from 300 to 970 nm. Further, the effects of electron‐donating and accepting unit on electrochemical and optical properties have been investigated.