[(2-Dimesitylboryl)phenyl]ethynyl-Substituted [2.2]Paracyclophane Exhibiting Circularly Polarized Luminescence in...

Developing a new type of circularly polarized luminescent active small organic molecule that combines high fluorescence quantum yield and luminescence dissymmetric factor in both solution and solid state is highly challenging but promising. In this context, we designed and synthesized a unique triarylborane-based [2.2]paracyclophane derivative, , in which an electron-accepting [(2-dimesitylboryl)phenyl]ethynyl group and an electron-donating N,N-diphenylamino group are introduced into two different benzene rings of [2.2]paracyclophane. Owing to the electronic effect of these two substituents, this compound can display charge-transfer emission with large Stokes shifts (∆υ = 4.23 - 8.20 × 10³ cm^-1) and fair quantum yields (Φ_F = 0.15 - 0.37) in solutions. In addition, this compound can emit strong blue fluorescence in the solid state with quantum yields that are even much higher than in solution (Φ_F up to 0.64 in powder and spin-coated film). Moreover, the enantiomeric forms of can show strong CPL signals in both dilute solution and solid state with |g_lum|s up to 9.6 × 10^-3 and 5.4 × 10^-3, respectively. Thus, it is possible to achieve tunable CPL from blue to yellow in solution with high B_CPLs ranging from 56.7 to 26.6 M^-1 cm^-1 and intense blue CPL combing high Φ_F and |g_lum| in the solid state.