Triple B←N Lewis Pair-Functionalized Triazatruxenes with Large Stokes Shifts.

A novel class of multiple B←N Lewis pair-functionalized polycyclic aromatic hydrocarbons with different BR 2 groups (R = Cl or Et) directly attached at positions 1, 6, and 11 of triazatruxene was synthesized. The triazatruxene backbone of 4 displays a bowl shape, and its molecular skeleton shows a highly twisted propeller-like structure with C 3 symmetry. The introduction of B←N Lewis pairs not only results in a large decrease in the HOMO-LUMO gap but also lowers the LUMO to -3.00 eV. Both compounds show excellent stability with large Stokes shifts of ≤8234 cm -1 and solvatochromic emission in solvents of different polarities.