Tunable circularly polarized luminescence of D-A type chiral conjugated oligomers via achiral donors

Abstract

Chiral conjugated oligomers with circularly polarized luminescence (CPL) have received great interest and been extensively researched. However, chiral conjugated oligomers with donor-acceptor (D-A) structures are poorly developed. In this paper, a series of D-A type chiral conjugated oligomers were synthesized by the copolymerization of axially chiral acceptors and achiral donors through Pd-catalyzed Buchwald-Hartwig C-N coupling reactions. The resulting chiral conjugated oligomers exhibit donor dependent fluorescence in solution with emission wavelength ranging from 500 to 574 nm and photoluminescence quantum yields (ФPL) up to 49%, which can be attributed to ICT transition derived from the D-A oligomer backbone. Obvious CPL response signals can be detected for the chiral conjugated oligomers with luminescence dissymmetry factors (glum) up to 1.3 × 10-3, which can be tuned via the variation of achiral donors. This work can provide a novel strategy for the design of chiral conjugated polymers or oligomers with D-A structure and tunable CPL signals.