Work Group Prof. Dr. F. Temps

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XMP paper selected as Editor's Research Highlight in Focus on Chemistry

Kiel, 30 January 2017:

     molecules logo
       
 

We happily report that the chief editor of MDPI has selected our recent paper in Molecules, vol. 22, p. 160 (2017) by Katharina Röttger, Rebecca Stellmacher, Mayra C. Stuhldreier and Friedrich Temps on the

Ultrafast Electronic Deactivation Dynamics of Xanthosine Monophosphate

as Research Highlight in the January 30 edition of Focus on Chemistry.

Abstract: Ultrafast energy dissipation is a crucial factor for the photostability of DNA and RNA, but even some of the key electronic deactivation pathways in monomeric nucleic acid building stones are still controversial. Here, we report on the excited-state dynamics of the rare nucleotide xanthosine monophosphate as a function of deprotonation state (XMP vs. XMP ) and excitation wavelength ( λpump =  278–243 nm) by femtosecond time-resolved fluorescence and absorption spectroscopy. We show that the predominating relaxation channel leads to a return of the photo-excited molecules to the electronic ground state in τ ∼ 1 ps. The mechanism likely involves an out-of-plane deformation of the five-membered ring, different from the main electronic deactivation pathways in the canonical purine bases adenine and guanine. The results are discussed in terms of the structural and electronic differences of XMP compared to the canonical nucleotides.

To read the full article see: DOI 10.3390/molecules22010160 

  

New SFB 677 video podcast online: "Ultrafast Molecular Switches Caught in the Act"

Kiel, 15 December 2015:

Photochemically driven molecular switches are extremely fast: Typically, the switching process takes just 1 picosecond (10‑12 s). To understand the underlying molecular mechanisms, it is necessary therefore to investigate them on the time scale of femtoseconds (10‑15 s). Experimentally, this can be done with modern methods of ultrafast spectroscopy, as applied in our work group. In complementary work, the molecular switching dynamics is simulated theoretically in the group of Professor Bernd Hartke. A new video podcast by the Kiel CRC 677 "Function by Switching" illustrates our approach:  

  

SFB video podcast
Click on image to start the video in a new page.
 

 

In combined studies of this kind within CRC 677, the photochemical mechanisms of basic switches like azobenzenes and furylfulgides have been analyzed in high details. This, in turn, allows us to systematically improve these molecules, i.e. to develop molecular systems that can be switched from one state to the other more selectively, more rapidly, more efficiently and more robustly. These achievements directly translate to improved applications of the switches, for example in functional materials or as tiny actuators and motors in molecular machines. The video podcast illustrates one of our improvements: An additional bridge between the two phenyl rings of azobenzene improves its switching properties dramatically, by shortening the molecular pathways from one state to the other, and by eliminating other molecular movements that would reduce the switching efficiency. Additionally, the bridge separates the excitation light wavelengths for the forward and backward switching directions. 

  

Friedrich Temps receives Wilhelm Jost Medal

Göttingen, 10 December 2015:

       F. Wilhelm Jost
F. Wilhelm Jost

Friedrich Temps received the Wilhelm Jost Medal of the Academy of Sciences Göttingen for the 2015 Wilhelm Jost Memorial Lecture

"Ultrafast Light-Induced Transformations in Molecular Switches and DNA Building Blocks"   

The Wilhelm Jost Memorial Lecture and Medal is awarded by the Academy of Sciences Göttingen and jointly by the Deutsche Bunsengesellschaft für Physikalische Chemie to commemorate the many scientific achievements and merits of F. Wilhelm Jost (1903 - 1968). The Lecture is traditionally given at the former work places of W. Jost, in Halle, Berlin, Hannover, Leipzig, Marburg, Darmstadt and Göttingen. The medal is presented after the last lecture in Göttingen.

Links to lecture scheduleAcademy of Sciences Göttingenlist of previous Jost lecturerslarger photo of Jost Medal.