Functionalized BF2 chelated azadipyrromethene dyes

Fluorescent molecules that emit in the near infra-red are potentially useful as probes for biotechnology. A relatively under-explored design for probes of this type are the aza-BODIPY dyes; this study was performed to enhance our understanding of these materials and ways in which they may be used in dye cassette systems. Thus, the aza-BODIPY dyes 1a – g were prepared. An advanced intermediate towards an eighth compound in the series, 6h , was made but it could not be complexed with boron effectively to give 1h . Spectroscopic properties of these compounds were recorded, and correlations between substituent effects, UV absorbance, fluorescence emissions, and quantum yields were made. Compound 1a was coupled with a fluorescein-alkyne derivative to give the energy transfer cassettes 2 and 3 . Both these compounds gave poor energy transfer, and the possible reasons for this were discussed.