LAUSR

Abstract Five BODIPY derivatives containing different number of styryl units were designed and synthesized based on the Knoevenagel reactions. All compounds were characterized by NMR and HRMS. The single crystal structures of compounds 1 and 3–5 were confirmed by X-ray crystallography. The photophysical and electrochemical properties of these dyes were also investigated by UV/Vis spectroscopy, fluorescence spectroscopy, and cyclic voltammetry. Our study indicates that the optical and electronic properties of the BODIPY derivatives could be easily tuned by the introduction of a various number of styryl units. Their absorption and emission spectra become gradually bathochromically shifted from the red region to the near-infrared region. Their first reduction and first oxidation potential (HOMO-LUMO gap) changes from 2.45 to 1.62 V. The structure-optical property relationships of these compounds are also systematically studied. Furthermore, cellular uptake experiments suggest that compounds 1–3 are membrane permeable and promising fluorophores for bio-labeling/imaging applications.