Skip to main content

Lund University Publications

LUND UNIVERSITY LIBRARIES

Excited‐State Topology Modifications of the Dihydroazulene Photoswitch Through Aromaticity

Skov, Anders B. ; Ree, Nicolai ; Gertsen, Anders S. ; Chabera, Pavel LU ; Uhlig, Jens LU ; Lissau, Jonas S. ; Nucci, Luigi ; Pullerits, Tõnu LU ; Mikkelsen, Kurt V. and Brøndsted Nielsen, Mogens , et al. (2019) In ChemPhotoChem 3(8). p.619-629
Abstract
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... (More)
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. (Less)
Please use this url to cite or link to this publication:
author
; ; ; ; ; ; ; ; and , et al. (More)
; ; ; ; ; ; ; ; ; ; and (Less)
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
ChemPhotoChem
volume
3
issue
8
pages
619 - 629
publisher
Wiley-Blackwell
external identifiers
  • scopus:85078465338
ISSN
2367-0932
DOI
10.1002/cptc.201900088
language
English
LU publication?
yes
id
c9e539d1-0df4-4387-b7ea-0f0234b87322
date added to LUP
2020-02-11 06:47:29
date last changed
2023-11-05 11:49:47
@article{c9e539d1-0df4-4387-b7ea-0f0234b87322,
  abstract     = {{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.}},
  author       = {{Skov, Anders B. and Ree, Nicolai and Gertsen, Anders S. and Chabera, Pavel and Uhlig, Jens and Lissau, Jonas S. and Nucci, Luigi and Pullerits, Tõnu and Mikkelsen, Kurt V. and Brøndsted Nielsen, Mogens and Sølling, Theis I. and Hansen, Thorsten}},
  issn         = {{2367-0932}},
  language     = {{eng}},
  number       = {{8}},
  pages        = {{619--629}},
  publisher    = {{Wiley-Blackwell}},
  series       = {{ChemPhotoChem}},
  title        = {{Excited‐State Topology Modifications of the Dihydroazulene Photoswitch Through Aromaticity}},
  url          = {{http://dx.doi.org/10.1002/cptc.201900088}},
  doi          = {{10.1002/cptc.201900088}},
  volume       = {{3}},
  year         = {{2019}},
}