Blue Emission BODIPY Dyes: Synthesis and Characterization

BODIPY (Boron Dipyrromethene) dyes have been studied for their high fluorescence intensity and small Stoke’s Shift. This molecule can be substituted in different positions to tweak the emission wavelength as well as responses to several conditions or environments like metal coordination or acidity. However, the molecules reported in the literature usually emit at wavelengths ranging from green (500 nm) to near-IR (800 nm). Our research interest has been based on 8-methylthiol-BODIPY because methylthiol is a good leaving moiety and substitution is relatively easy. More recently, we have explored a method to create blue emission BODIPY dyes by the incorporation of an amine group to the BODIPY backbone. While studying their optical properties we encountered that some molecules exhibit sensitivity to solvent polarity while others for acidity. We even found one BODIPY that was a total surprise since no fluorescence whatsoever was observed. X-ray crystallography was used to determine the crystal packing and the interactions in the solid phase which were useful for determining the cause for the lack of emission in the BODIPY dye previously mentioned. We would like present our expanding library of amino-BODIPY dyes in which even a methyl group can change drastically the emission properties. We acknowledge support for this work from the Welch Foundation and R.R. wishes to acknowledge UTEP-LSAMP.