title: Folding-induced modulation of excited-state dynamics in an oligophenylene-ethynylene-tethered spiral perylene bisimide aggregate.
abstract: The excited-state photophysical behavior of a spiral perylene bisimide (PBI) folda-octamer (F8) tethered to an oligophenylene-ethynylene scaffold is comprehensively investigated. Solvent-dependent UV/Vis and fluorescence studies reveal that the degree of folding in this foldamer is extremely sensitive to the solvent, thus giving rise to an extended conformation in CHCl(3) and a folded helical aggregate in methylcyclohexane (MCH). The exciton-deactivation dynamics are largely governed by the supramolecular structure of F8. Femtosecond transient absorption (TA) in the near-infrared region indicates a photoinduced electron-transfer process from the backbone to the PBI core in the extended conformation, whereas excitation power- and polarization-dependent TA measurements combined with computational modeling showed that excitation energy transfer between the unit PBI chromophores is the major deactivation pathway in the folded counterpart.
authors.affiliation: Spectroscopy Laboratory for Functional, π-Electronic Systems and Department of Chemistry, Yonsei University, Seoul 120-749 (Korea).
authors.forename: Minjung
authors.initials: M
authors.lastname: Son
authors.affiliation: Institut für Organische Chemie & Center for Nanosystems Chemistry, Universität Würzburg, Am Hubland, 97074 Würzburg (Germany).
authors.forename: Benjamin
authors.initials: B
authors.lastname: Fimmel
authors.affiliation: Institut für Organische Chemie & Center for Nanosystems Chemistry, Universität Würzburg, Am Hubland, 97074 Würzburg (Germany).
authors.forename: Volker
authors.initials: V
authors.lastname: Dehm
authors.affiliation: Institut für Organische Chemie & Center for Nanosystems Chemistry, Universität Würzburg, Am Hubland, 97074 Würzburg (Germany). wuerthner@chemie.uni-wuerzburg.de.
authors.forename: Frank
authors.initials: F
authors.lastname: Würthner
authors.affiliation: Spectroscopy Laboratory for Functional, π-Electronic Systems and Department of Chemistry, Yonsei University, Seoul 120-749 (Korea). dongho@yonsei.ac.kr.
authors.forename: Dongho
authors.initials: D
authors.lastname: Kim
keywords: excited state; foldamers; perylene bisimide; self-assembly; time-resolved spectroscopy