Light harvesting vesicular donor-acceptor scaffold limits the rate of charge recombination in the presence of an electron donor

We report the synthesis and excited state properties of a single component light harvesting donor-acceptor dyad (R/S)-NP(OH)(2) containing an alpha,beta-dihydroxypropyl side-chain that can undergo molecule-bilayer-vesicle-gel-crystal transition. By virtue of steric hindrance offered by orthogonal naphthalimide and 2,6-diisopropylphenyl substituents, very weak H-type excitonic interactions between the perylenimide units resulted in high fluorescence quantum yield in the dyad-based metastable vesicular gel having a near-quantitative excitation energy transfer from naphthalimide to perylenimide. Femtosecond transient absorption measurements of the dyad (R/S)-NP(OH)(2) : indole co-gel show that the vesicular scaffold promoted extension of the survival time of charge separated states (similar to 1.4 ns) when compared to ultrafast charge recombination (similar to 6 ps) in dyad (R/S)-NP(OH)(2) : indole solution.