Synthesis of Highly Functionalized BOPHY Chromophores Displaying Large Stokes Shifts.

BOPHY dyes bearing bromo (in 5,5'-position) and iodo (in 4,4'-position) were synthesized. Double Knoevenagel reactions allow the extension of conjugation, resulting in an absorption above 625 nm. Selective cross-coupling reactions promoted by palladium(0) and microwave irradiation allow linking of a perylene module. These dyes are highly fluorescent, and the intramolecular cascade energy transfer from the perylene moiety to the BOPHY framework is almost quantitative, providing large virtual Stoke shifts (>5100 cm(-1)).