Work Group Prof. Dr. F. Temps

Multi-azobenzene switches

In functional systems, photoswitches are typically embedded in complex environments, where the close proximity of the chromophores leads to cooperative phenomena, e.g. steric interactions, excitonic coupling, charge-transfer (CT) and direct electronic coupling in π-conjugated systems. All of these mechanisms may compete with the desired photoisomerization. To elucidate the ensuing influences, we investigate prototypical photoswitchable multi-azobenzene compounds, such as bis[4-(phenylazo)-phenyl]amine (BPAPA) and tris[4-(phenylazo)phenyl]amine (TPAPA), where the AB units are connected via an amino linker to enable electronic coupling between the chromophores, in comparison to the parent compound 4-aminoazobenzene (AAB) for reference.

BPAPA and TPAPA
 
Structures of bis[4-(phenylazo)-phenyl]amine (BPAPA) and tris[4-(phenylazo)phenyl]amine (TPAPA).

  

Important Papers:

  • T. G. Gopakamur, T. Davran-Candan, J. Bahrenburg, R. J. Maurer, F. Temps, K. Reuter, R. Berndt, "Broken Symmetry of an Adsorbed Molecular Switch Determined by Scanning Tunneling Spectroscopy", Angew. Chem. Int. Ed. 52, 11007 - 11070 (2013). DOI: 10.1002/anie.201305027
  • J. Bahrenburg, C. M. Sievers, J. B. Schönborn, B. Hartke, F. Renth F. Temps, C. Näther, F. D. Sönnichsen, "Photochemical Properties of Multi-Azobenzene Compounds", Photochem. Photobiol. Sci. 12, 511 - 518 (2013). DOI:  10.1039/C2PP25291K