Star-shaped supramolecular multichromophoric array from bodipy dyes grafted on truxene core

Supramolecular multichromophoric systems containing photoactive subunits are extensively investigated for both fundamental and applicative reasons. Several such reasons are linked to the possibility for properly designed multichromophoric architectures to behave as light-harvesting antennae for application in solar energy conversion devices. Difluoroborondipyrromethene species (Bodipy) are quite interesting dyes, since they exhibit strong visible absorption and intense luminescence, which can be tuned in energy and lifetime by incorporating suitable substituents on the organic framework. Truxene species are recently characterized chromophores, which can play the role of photoactive cores for multichromophoric systems. Bodipy dyes and truxene species are compatible systems from a photochemical point of view, since they absorb at different wavelengths (essentially UV region for truxene species, visible for the Bodipy dyes), so they can be addressed separately, to a large extent. By taking advantage of the structural and photophysical properties of truxene derivatives and Bodipy molecules, we prepared a novel star-shaped supramolecular system containing three different bodipy dyes logically arranged around a truxene core. This is the first time that Bodipy and truxene chromophores are linked into the same (super)molecule. Luminescence experiments have shown that the star-shaped molecule features highly efficient and fast energy migration processes. Both Dexter-type (from the truxene core to the peripheral Bodipys) and Foerster-type (between the peripheral Bodipy subunits) mechanisms likely contribute to the overall energy migration process.