Ultrafast molecular switches caught in the act

Published on December 1, 2015

Photochemically driven molecular switches may serve as motor units in future nanoscale machines. To design such motor units, we need to understand and improve the photochemical dynamics of molecular switches.


In CRC 677, scientists from physical, organic and theoretical chemistry are working together towards this aim. In one of these research lines, the well-known molecular switch azobenzene could be improved significantly, by joining the two phenyl rings with an additional ethylenic bridge. With advanced methods of physical and theoretical chemistry, working hand in hand, it was possible to analyze the molecular movements on the femtosecond time scale and to fully understand the reasons for the improved photophysical properties of bridged azobenzene. In ongoing work, further improvements have already been achieved and embeddings of these new photochemical switches into complex molecular environments are studied.

Hartke Group and Temps Group | Christian-Albrechts-University of Kiel, Germany

Prof. Friedrich Temps leads the ultrafast spectroscopy group at the Institute of Physical Chemistry, Christian-Albrechts-University of Kiel. His group investigates chemical reaction dynamics using state-of-the-art femtosecond laser experiments with wavelengths ranging from mid-infrared to ultraviolet.

Prof. Bernd Hartke is head of the theoretical chemistry group at the Institute of Physical Chemistry, Christian-Albrechts-University of Kiel. One of the research topics in his group is computational simulation of photochemically triggered molecular dynamics.

Dr. Julia Bahrenburg has recently completed her PhD studies in the Temps group, on femtosecond spectroscopy studies involving several different molecular switches.

M.Sc. Ronja Höppner is a PhD student in the Hartke group, working on the design of new photoswitches and on simulations of their dynamics.


Siewertsen, R., Neumann, H., Buchheim-Stehn, B., Herges, R., Näther, C., Renth F., and Temps, F.: Highly Efficient Reversible Z−E Photoisomerization of a Bridged Azobenzene with Visible Light through Resolved S1(n-pi-star) Absorption Bands J. Am. Chem. Soc. 2009, 131,15594–15595, DOI: 10.1021/ja906547d

Carstensen, O., Sielk, J., Schönborn, J., Granucci, G. and Hartke, B.: Unusual photochemical dynamics of a bridged azobenzene derivative J. Chem. Phys. 2010, 53,124305, DOI: 10.1063/1.3479397

Siewertsen, R., Schönborn, J.B., Hartke, B., Renth F. and Temps, F.: Superior photoswitching dynamics of dihydrodibenzodiazocine, a bridged azobenzene Phys. Chem. Chem. Phys. 2011, 13,1054–1063, DOI: 10.1039/c0cp01148g

Carstensen, N. O.: QM/MM surface-hopping dynamics of a bridged azobenzene derivative Phys. Chem. Chem. Phys. 2013, 15,15017-15026, DOI: 10.1039/c3cp50606a.

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