Water-soluble bodipys: syntheses, derivatization and photophysical studies

A set of water-soluble 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) derivatives, has been prepared and their spectroscopic properties examined. These dyes can be used as either donor or acceptor in synthesis of through-bond energy transfer cassettes. Sulfonation conditions were developed for several BODIPY dyes to give the mono-sulfonated and di-sulfonated products. Compounds with an aryl iodide could be used for organometallic couplings. Similarly, BODIPYs with an aromatic bromide, but also two chlorine atoms could be replaced via SNAr reactions. The amine sulfonated BODIPY is amenable to couple to biomolecules via acylation reactions. A diazotization/azide reaction sequence was used to convert the amines into azides; the latter may be functionalized via click reactions. Spectral data for these materials indicates they are highly fluorescent probes in aqueous environments. We have also prepared some lipophilic BODIPY derivatives, which can be used for SNAr reactions and make some through-bond, energy transfer cassettes. DichloroBODIPYs can also be used for labeling proteins successfully.