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.