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Conformations and Photophysics of a Stilbene Dimer.

Ruseckas, Arvydas; Namdas, Ebinazar B; Lee, J Y; Mukamel, S; Wang, S J; Bazan, G C and Sundström, Villy LU (2003) In The Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory 107(40). p.8029-8034
Abstract
Photophysical studies of pseudo-p-distyryl[2.2]paracyclophane, a model molecule of a stilbene dimer arranged in a brick-wall geometry, in tetrahydrofurane solution indicate the existence of at least two conformers in the ground state. The conformer A with the smallest optical gap of 3 eV has a short radiative lifetime of 3.3 ns, while the conformer B with an optical gap about 0.3 eV larger is much more abundant in solution and its radiative lifetime is about 10 times longer. Ab initio calculations show that the ground-state energy has a shallow minimum with respect to the torsional angle between the styryl side group and the paracyclophane core around the zero position, with the lowest energy conformation at a torsional angle of -21. On... (More)
Photophysical studies of pseudo-p-distyryl[2.2]paracyclophane, a model molecule of a stilbene dimer arranged in a brick-wall geometry, in tetrahydrofurane solution indicate the existence of at least two conformers in the ground state. The conformer A with the smallest optical gap of 3 eV has a short radiative lifetime of 3.3 ns, while the conformer B with an optical gap about 0.3 eV larger is much more abundant in solution and its radiative lifetime is about 10 times longer. Ab initio calculations show that the ground-state energy has a shallow minimum with respect to the torsional angle between the styryl side group and the paracyclophane core around the zero position, with the lowest energy conformation at a torsional angle of -21. On this basis, A and B are assigned to flat and twisted conformations, respectively. Conformer B shows a partial decay of excited-state absorption and fluorescence with a time constant ranging from 5 to 30 ps, depending on excitation photon energy. We attribute this to isomerization of the stilbene moiety, which initially keeps conjugation in the ground state. The isomerization product is long-lived and tends to accumulate in solution. (Less)
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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
The Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory
volume
107
issue
40
pages
8029 - 8034
publisher
The American Chemical Society
external identifiers
  • wos:000185757100004
  • scopus:0242270985
ISSN
1520-5215
DOI
10.1021/jp027536m
language
English
LU publication?
yes
id
0b993f16-8cef-4363-aecc-42e673b3293e (old id 128205)
date added to LUP
2007-07-03 16:32:17
date last changed
2017-08-20 04:17:35
@article{0b993f16-8cef-4363-aecc-42e673b3293e,
  abstract     = {Photophysical studies of pseudo-p-distyryl[2.2]paracyclophane, a model molecule of a stilbene dimer arranged in a brick-wall geometry, in tetrahydrofurane solution indicate the existence of at least two conformers in the ground state. The conformer A with the smallest optical gap of 3 eV has a short radiative lifetime of 3.3 ns, while the conformer B with an optical gap about 0.3 eV larger is much more abundant in solution and its radiative lifetime is about 10 times longer. Ab initio calculations show that the ground-state energy has a shallow minimum with respect to the torsional angle between the styryl side group and the paracyclophane core around the zero position, with the lowest energy conformation at a torsional angle of -21. On this basis, A and B are assigned to flat and twisted conformations, respectively. Conformer B shows a partial decay of excited-state absorption and fluorescence with a time constant ranging from 5 to 30 ps, depending on excitation photon energy. We attribute this to isomerization of the stilbene moiety, which initially keeps conjugation in the ground state. The isomerization product is long-lived and tends to accumulate in solution.},
  author       = {Ruseckas, Arvydas and Namdas, Ebinazar B and Lee, J Y and Mukamel, S and Wang, S J and Bazan, G C and Sundström, Villy},
  issn         = {1520-5215},
  language     = {eng},
  number       = {40},
  pages        = {8029--8034},
  publisher    = {The American Chemical Society},
  series       = {The Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory},
  title        = {Conformations and Photophysics of a Stilbene Dimer.},
  url          = {http://dx.doi.org/10.1021/jp027536m},
  volume       = {107},
  year         = {2003},
}