Directed Energy Transfer Funnels in Dendrimeric Antenna Supermolecules

We have studied the dynamics of directed, multistep energy transport in a class of fractal-like dendrimeric molecules. For particular forms of these highly branched phenylacetylene dendrimers, both theory and experiment put the lowest excitation energy at the center (locus) of the supermolecule. This results in a structurally symmetric and ordered exciton funnel, with a well-directed energy gradient. We have designed and synthesized a derivative of these dendrimers with a perylene moiety at the locus, which acts as an energy trap for the directed exciton funnel. Spectroscopic evidence indicates transfer efficiency of 98% from the photoabsorbing dendrimer backbone to the perylenic trap.