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).