Optical limiting properties of 2,6-dibromo-3,5-distyrylBODIPY dyes were investigated by using the z-scan technique at 532 nm in the nanosecond pulse range. A strong reverse saturable absorption response was observed even in solution, which suggests that compounds of this type are potentially suitable for use in optical limiting applications.
The ease of functionalization of BODIPY dyes provides scope for preparing pH indicators by introducing suitable functional groups. In this work, two dimethylamino substituted BODIPY dyes 3 and 4 with styryl and phenylbuta-1,3-dienyl groups introduced at the 3,5-positions were synthesized, characterized, and studied for use as pH indicators. Incorporation of the electron-rich vinylene substituents yielded dyes that absorb in the NIR region with emission wavelengths of 796 and 797 nm for 3 and 4, respectively, in dimethylsulfoxide (DMSO). Time-dependent density functional theory (TD-DFT) calculations were performed to study the effect of adding an extra alkene bond in 4 on the photophysical properties. The extra alkene bond in 4 resulted in a 3 nm shift in the main NIR region absorption band, lower molar extinction coefficient values, higher emission wavelength, and a decrease in fluorescence quantum yield in all solvents studied. Upon protonation of the amino groups, a large blue shift is observed in both the absorption and emission wavelengths, along with an increase in the fluorescence quantum yields and longer fluorescence lifetimes. The [Formula: see text] values for 3 and 4 were estimated to be 2.9 (± 0.05) and 1.2 (± 0.05), respectively.