title: Rapid energy transfer in cascade-type bodipy dyes.
abstract: Three new molecular dyads, comprising a bora-3a,4a-diaza-s-indacene (Bodipy) dye linked to two aromatic polycycles via the boron center, have been synthesized and fully characterized. The polycyclic compounds are either pyrene or perylene, or a mixture of both. Whereas the absorption spectral profiles contain important contributions from each of the subunits, fluorescence occurs exclusively from the Bodipy fragment. Intramolecular excitation energy transfer is extremely efficient in each case, even though spectral overlap integrals for the pyrene-based system are modest. Although these polycycles are sterically congested, molecular dynamics simulations indicate that they are in dynamic motion, and this hinders proper computation of the orientation factors for Förster-type energy transfer. These new dyes, especially the mixed polycycle system, greatly extend the range of excitation wavelengths that can be used for fluorescence microscopy.
authors.affiliation: Molecular Photonics Laboratory, School of Natural Sciences, Bedson Building, University of Newcastle, Newcastle upon Tyne NE1 7RU, United Kingdom. anthony.harriman@ncl.ac.uk
authors.forename: Anthony
authors.initials: A
authors.lastname: Harriman
authors.forename: Guillaume
authors.initials: G
authors.lastname: Izzet
authors.forename: Raymond
authors.initials: R
authors.lastname: Ziessel