Triptycene-Based Luminescent Materials in Homoconjugated Charge-Transfer Systems: Synthesis, Electronic Structures, AIE Activity, and Highly Tunable Emissions

We have developed a new family of luminescent materials featuring through-space charge transfer from electron donors to acceptors that are electronically separated by triptycene. Most of these molecules are highly fluorescent, and modulation of their emissions was achieved by tuning the electron-accepting strength in a range from the weak triptycene acceptor over triarylborane (BMes) to strongly accepting naphthalimide (Npa) moieties. Pz-Pz shows an aggregation-induced emission in aggregates and in the solid state coupled with a highly red-shifted broad emission (ca. 160 nm) of the excimer, indicating that phenothiazine (Pz) also plays a vital role in the emission responses as an electron donor. This work may help develop new approaches to photophysical mechanism based on the rigid, homoconjugated, and structurally unusual 3D triptycene scaffold.