AIE luminogens based on 9, 10-dithienylanthracene with a D-A-D structure: Design, synthesis and application in cell imaging.

Three novel D-A-D-structured emitters derived from 9, 10-dithienylanthracene derivatives (DTAs) were synthesized and characterized. These DTAs consist of substituted 9-phenyl-9H-carbazole (BPCB-DTA), triphenylamine (BTPA-DTA) and N, N-dimethylaniline (BDMA-DTA) as donor units, with the phenylacetonitrile group serving as the acceptor. The impact of steric hindrance and electronic effect of the substituents on the optical properties has been thoroughly discussed. All DTAs exhibited aggregation-induced emission, except for BDMA-DTA, which displayed gradual fluorescence quenching as the water fraction increased from 0 to 90 %. Scanning electron microscope analysis revealed that aggregates formed morphologically regular nanorods due to the self-assembled process. Moreover, BPCB-DTA and BTPA-DTA demonstrated reversible mechanofluorochromic and vapochromic luminescence behaviors with a high color contrast mechanofluorochromism ranging from yellow to bright green coloration. These results suggest that large volume and non-coplanar fluorophores play a crucial role in constructing DTA-type AIE dyes. Additionally, fluorescence imaging experiments conducted on HeLa cells confirmed the bio-imaging capabilities of these DTAs.