Deep red aggregation-induced CPL emission behavior of four-component tunable AIE-active chiral polymers via two FRET pairs mechanism

Abstract

Two four-component chiral polymers with two Förster resonance energy transfer (FRET) pairs incorporating chiral 1,1′-binaphthyl, 4,7- di(thiophen-2-yl)-2,1,3-benzothiadiazole (DTBT), tetraphenylethene (TPE) and fluorene moieties were designed and synthesized via one-pot two-step of Pd-catalyzed Sonogashira reaction and Suzuki reaction by changing different ratios of DTBT chromophore and AIE-active TPE group. Both chiral polymers exhibit large Stokes shift (257 nm) and tunable red aggregation-induced emission (AIE) response behavior via two intramolecular FRET pairs by changing excitation wavelength. Interestingly, the chiral polymer with lower ratio of DTBT (P-1) shows obvious aggregation-induced circularly polarized luminescence (AICPL) emission signals in deep red region (around 650 nm) and higher glum, which can reach as high as ±2.0 × 10-3 in THF-H2O mixtures.