title: DNA-Based Oligochromophores as Light-Harvesting Systems.
abstract: The chromophores ethynyl pyrene as blue, ethynyl perylene as green and ethynyl Nile red as red emitter were conjugated to the 5-position of 2'-deoxyuridine via an acetylene bridge. Using phosphoramidite chemistry on solid phase labelled DNA duplexes were prepared that bear single chromophore modifications, and binary and ternary combinations of these chromophore modifications. The steady-state and time-resolved fluorescence spectra of all three chromophores were studied in these modified DNA duplexes. An energy-transfer cascade occurs from ethynyl pyrene over ethynyl perylene to ethynyl Nile red and subsequently an electron-transfer cascade in the opposite direction (from ethynyl Nile red to ethynyl perylene or ethynyl pyrene, but not from ethynyl perylene to ethynyl pyrene). The electron-transfer processes finally provide charge separation. The efficiencies by these energy and electron-transfer processes can be tuned by the distances between the chromophores and the sequences. Most importantly, excitation at any wavelength between 350 and 700 nm finally leads to charge separated states which make these DNA samples promising candidates for light-harvesting systems.
authors.affiliation: Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe (Germany).
authors.forename: Philipp
authors.initials: P
authors.lastname: Ensslen
authors.affiliation: Institute of Physical and Theoretical Chemistry, University of Regensburg, Universitätsstr. 31, 93053 Regensburg (Germany).
authors.forename: Fabian
authors.initials: F
authors.lastname: Brandl
authors.affiliation: Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe (Germany).
authors.forename: Sabrina
authors.initials: S
authors.lastname: Sezi
authors.affiliation: Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe (Germany).
authors.forename: Reji
authors.initials: R
authors.lastname: Varghese
authors.affiliation: Institute of Physical and Theoretical Chemistry, University of Regensburg, Universitätsstr. 31, 93053 Regensburg (Germany).
authors.forename: Roger-Jan
authors.initials: RJ
authors.lastname: Kutta
authors.affiliation: Institute of Physical and Theoretical Chemistry, University of Regensburg, Universitätsstr. 31, 93053 Regensburg (Germany).
authors.forename: Bernhard
authors.initials: B
authors.lastname: Dick
authors.affiliation: Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe (Germany). Wagenknecht@kit.edu.
authors.forename: Hans-Achim
authors.initials: HA
authors.lastname: Wagenknecht
mesh_terms: D001483:Base Sequence; D004247:DNA / Q000737:chemistry*; D004579:Electron Transport; D004735:Energy Transfer; D005453:Fluorescence; D008027:Light; D009841:Oligonucleotides / Q000737:chemistry*; D010569:Perylene / Q000737:chemistry; D011721:Pyrenes / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet
chemical_list: D009841:Oligonucleotides; D011721:Pyrenes; D010569:Perylene; D004247:DNA; C030984:pyrene
keywords: electron transfer; energy transfer; fluorescence; helix; oligonucleotides