Erlangen 2018 – wissenschaftliches Programm
MO 2.4: Vortrag
Montag, 5. März 2018, 11:15–11:30, PA 1.150
Ultrafast Photoinduced Ring Closing in Photoswitchable Diarylethene-Based Nucleosides — •Jose Luis Perez Lustres1, Yang Li1, Hans Robert Volpp1, Tiago Buckup1, Theresa Kolmar2, Andres Jaeschke2, and Marcus Motzkus1 — 1PCI, Universität Heidelberg, Germany — 2IPMB, Universität Heidelberg, Germany
Diarylethene-based nucleosides are novel photoswitchable compounds, where the nucleobase forms the core of the molecular switch.(1) The latter undergoes ring closing/opening reactions upon conrotatory movement of the side chains. The process is reversible and occurs on ultrafast timescales with high yield.(2) Thus, these DNA building blocks are designed to control and report about DNA structure. We address here the ring closing reaction by broadband fs transient absorption in the near UV. The signature of the closed structure is detected in the sub picosecond timescale. Transient anisotropy indicates strong structural reorganisation occurring in the course of vibrational relaxation. Finally, spectral analysis of the non-decaying component demonstrates branching at the earliest stages of the photoreaction. The analysis is facilitated by a novel strategy to isolate the absorption coefficients of the open and closed forms from steady-state UV–Vis absorption spectra obtained during long time irradiation at selected wavelengths.
1. Cahova, H.; Jaeschke, A., Angew Chem Int Edit 2013, 52 (11), 3186-3190.
2. Buckup, T.; Sarter, Ch.; Volpp, H.-R.; Jaeschke, A.; Motzkus, M., J. Phys. Chem. Lett. 2015, 6, 4717-4721.