© 2015 Elsevier B.V. All rights reserved. A series of five mono-styryl and their corresponding symmetric di-styryl-2,6-diiodo-BODIPYs containing indolyl, pyrrolyl, thienyl or tri(ethylene glycol)phenyl groups were synthesized using Knoevenagel condensations. The yields for the condensation reactions were improved up to 40% using microwave irradiation (90 °C for 1 h at 400 W) due to lower decomposition of BODIPYs upon prolonged heating. The spectroscopic, structural (including the X-ray of a di-styryl-2,6-diiodo-BODIPY) and in vitro properties of the BODIPYs were investigated. The extension of π-conjugation through the 3,5-dimethyls of the known phototoxic 2,6-diiodo-BODIPY 1 produced bathochromic shifts in the absorption and emission spectra, in the order of 63-125 nm for the mono-styryl- and 128-220 nm for the di-styryl-BODIPYs in DMSO. The largest red-shifts were observed for the indolyl-containing BODIPYs while the largest fluorescence quantum yields were observed for the tri(ethyleneglycol)phenylstyryl-BODIPYs. Among this series, only the mono-styryl-BODIPYs were phototoxic (IC 50 = 2-15 μM at 1.5 J/cm 2 ), and were observed to localize preferentially in the cell ER and mitochondria. On the other hand, the di-styryl-BODIPYs were found to have low or no phototoxicity (IC 50 > 100 μM at 1.5 J/cm 2 ). Among this series of compounds BODIPY 2a shows the most promise for application as photosensitizer in PDT.
Publication Source (Journal or Book title)
Journal of Photochemistry and Photobiology B: Biology
Gibbs, J., Zhou, Z., Kessel, D., Fronczek, F., Pakhomova, S., & Vicente, M. (2015). Synthesis, spectroscopic, and in vitro investigations of 2,6-diiodo-BODIPYs with PDT and bioimaging applications. Journal of Photochemistry and Photobiology B: Biology, 145, 35-47. https://doi.org/10.1016/j.jphotobiol.2015.02.006