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

ABSTRACT 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 | g lum | 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 | g lum | values of 6.9–14.0 × 10 −3 .