title: The Three Possible 2-(Pyrenylethynyl) Adenosines: Rotameric Energy Barriers Govern the Photodynamics of These Structural Isomers.
abstract: This article presents a comprehensive study of the photophysics of 2-(2-pyrenylethynyl) adenosine and 2-(4-pyrenylethynyl) adenosine, which are structural isomers of the well-established fluorescent RNA label 2-(1-pyrenylethynyl) adenosine. We performed steady-state and ultrafast transient absorption spectroscopy studies along with time-resolved fluorescence emission experiments in different solvents to work out the interplay of locally excited and charge-transfer states. We found the ultrafast photodynamics to be crucial for the fluorescence decay behavior, which extends up to tens of nanoseconds and is partially multi-exponential. These features in the ultrafast dynamics are indicative of the rotational energy barriers in the first excited state.
authors.affiliation: Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue-Str. 7, 60438, Frankfurt, Germany.
authors.forename: Andreas J
authors.initials: AJ
authors.lastname: Reuss
authors.affiliation: Institute of Organic Chemistry and Chemical Biology, Goethe University Frankfurt, Max-von-Laue-Str. 7, 60438, Frankfurt, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Grünewald
authors.affiliation: Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue-Str. 7, 60438, Frankfurt, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Braun
authors.affiliation: Institute of Organic Chemistry and Chemical Biology, Goethe University Frankfurt, Max-von-Laue-Str. 7, 60438, Frankfurt, Germany.
authors.forename: Joachim W
authors.initials: JW
authors.lastname: Engels
authors.affiliation: Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue-Str. 7, 60438, Frankfurt, Germany. wveitl@theochem.uni-frankfurt.de.
authors.forename: Josef
authors.initials: J
authors.lastname: Wachtveitl
mesh_terms: D000241:Adenosine / Q000737:chemistry*; D007536:Isomerism; D015394:Molecular Structure; D011789:Quantum Theory; D013050:Spectrometry, Fluorescence
chemical_list: D000241:Adenosine
keywords: density functional calculations; fluorescent probes; photophysics; thermodynamics; time-resolved spectroscopy