Self-Assembly-Induced Ultrafast Photodriven Charge Separation in Perylene-3,4-dicarboximide-Based Hydrogen-Bonded Foldamers.

We report the synthesis, self-assembly characteristics, and ultrafast electron transfer dynamics of a perylene-3,4-dicarboximide (PMI) covalently linked to an N,N'-bis(3,4,5-tridodecyloxyphenyl)melamine electron donor (D) via a biphenyl spacer (PMI-Ph2-D). Synchrotron-based small- and wide-angle X-ray scattering (SAXS/WAXS) measurements in methylcyclohexane solution show that PMI-Ph2-D self-assembles into π-π stacked, hydrogen-bonded foldamers consisting of two or three hexameric rings or helices. Ultrafast transient absorption spectroscopy reveals that photoinduced charge separation within these nanostructures occurs by a unique pathway that is emergent in the assembly, whereas electron transfer does not occur in the PMI-Ph2-D monomers in tetrahydrofuran.