Axially Chiral Binaphthyl With Carbazole Donor and Cyano Acceptor: Circularly Polarized Fluorescence and Phosphorescence.

We investigated the chiroptical properties of an axially chiral binaphthyl derivative bearing a carbazole donor and a cyano acceptor, with particular emphasis on circularly polarized fluorescence (CPF) and circularly polarized phosphorescence (CPP). The compound was synthesized via Pd-catalyzed carbazole introduction followed by Ni(cod)2-mediated cyanation. Theoretical calculations revealed that the HOMO is localized on the carbazole donor, whereas the LUMO is distributed over the cyanonaphthalene acceptor, indicating intramolecular charge-transfer (ICT) character. Consequently, the emission spectra exhibited pronounced positive solvatochromism, accompanied by two fluorescence lifetime components (1.3-1.4 and 7.6-13 ns). The (S)-enantiomer showed positive circular dichroism and CPF signals independent of solvent polarity, with |glum| values of 1.9-3.1 × 10-3. In frozen 2-methyltetrahydrofuran, a well-resolved CPP spectrum with vibronic structure was observed, displaying an opposite sign relative to CPF and exhibiting enhanced |glum| values of 6.9-14.0 × 10-3.