The browser you are using is not supported by this website. All versions of Internet Explorer are no longer supported, either by us or Microsoft (read more here: https://www.microsoft.com/en-us/microsoft-365/windows/end-of-ie-support).

Please use a modern browser to fully experience our website, such as the newest versions of Edge, Chrome, Firefox or Safari etc.

Tönu Pullerits. Portrait.

Tönu Pullerits

Professor

Tönu Pullerits. Portrait.

Excited‐State Topology Modifications of the Dihydroazulene Photoswitch Through Aromaticity

Author

  • Anders B. Skov
  • Nicolai Ree
  • Anders S. Gertsen
  • Pavel Chabera
  • Jens Uhlig
  • Jonas S. Lissau
  • Luigi Nucci
  • Tõnu Pullerits
  • Kurt V. Mikkelsen
  • Mogens Brøndsted Nielsen
  • Theis I. Sølling
  • Thorsten Hansen
Show all

Summary, in English

The gain and loss of aromaticity plays a key role in organic chemistry and in the prediction of rate‐determining steps. Herein, we explore the concept of aromaticity in photoisomerization reactions. Benzannulated derivatives of the dihydroazulene‐vinylheptafulvene (DHA‐VHF) photoswitch were investigated using transient absorption spectroscopy and time‐dependent density functional theory to elucidate the effect of built‐in aromaticity on the switching properties. We found that benzannulation hampered the switching ability by enhancing an already existing barrier on the excited state surface. This enhancement was found to arise from a significant loss of aromaticity in the DHA‐to‐VHF transition state on the excited state potential energy surface. The VHF was found to be highly aromatic on the excited state surface, showing a reversal of aromaticity compared to the ground state. The barrier was found to be dependent on the position of benzannulation, since one derivative was found to switch as fast as the non‐benzannulated molecule although with lower efficiency, whereas another derivative completely lost the ability to undergo reversible photoswitching. The findings herein provide novel principles for the design of molecular photoswitches, shedding new light on excited state aromaticity, as previous discussions have mainly considered excited state aromaticity to be beneficial to switching. Our findings show that this view must be reconsidered.

Department/s

  • Chemical Physics
  • NanoLund: Centre for Nanoscience
  • eSSENCE: The e-Science Collaboration

Publishing year

2019

Language

English

Pages

619-629

Publication/Series

ChemPhotoChem

Volume

3

Issue

8

Document type

Journal article

Publisher

Wiley-VCH Verlag

Topic

  • Physical Chemistry (including Surface- and Colloid Chemistry)
  • Atom and Molecular Physics and Optics

Status

Published

ISBN/ISSN/Other

  • ISSN: 2367-0932