Abstract
The electric field photogenerated by an electron donor-acceptor pair is probed with a covalently attached dye molecule using transient absorption spectroscopy. The donor molecule, 4-X-naphthalene-1,8-dicarboximide (Dx) (where X is (1) piperidine or (2) pyrrolidine), is directly attached to the 1,4,5,8-naphthalenetetracarboxydiimide acceptor (A), which is attached through a benzene spacer to the probe molecule, 4,4-difluoro-3,5-dimethyl-4-bora-3a, 4a-diaza-s-indacene (P). A ~150fs laser pulse at 412nm selectively excites Dx. The transition dipole of P is approximately perpendicular to the direction of the electric field generated by DX-A~, minimizing the rate of excitation energy transfer from DJ to P, whereas the maximum change in the state dipole upon excitation is parallel to the electric field, maximizing Stark-shift effects. The groundstate absorption spectrum of P in 1,4-dioxane (Ama)( = 512 nm) blue-shifts 5 + 1 nm and bleaches as the nearby radical pair (DX-A~) forms. The band-shift effect diminishes in the higher polarity solvents tetrahydrofuran and butyronitrile but does not disappear completely. Solvatochromism measurements performed at room temperature and conventional electrochromism measurements performed at 77 K on P alone, indicate that the state dipole of P decreases by 2.0+0.2 D upon excitation to the first excited singlet state. From this change in dipole moment and the observed band-shift in DX-A-P, the effective electric field due to the charge-separated pair, experienced by P in 1,4-dioxane, is found to be 6±1 MV/cm. '
| Original language | English |
|---|---|
| Pages (from-to) | 815-828 |
| Number of pages | 14 |
| Journal | New Journal of Chemistry |
| Volume | 20 |
| Issue number | 7-8 |
| Publication status | Published - 1996 |
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A molecular probe of the electric field produced by a photogenerated ion pair. / Debreczeny, Martin P.; Svec, Walter A.; Wasielewski, Michael R.
In: New Journal of Chemistry, Vol. 20, No. 7-8, 1996, p. 815-828.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - A molecular probe of the electric field produced by a photogenerated ion pair
AU - Debreczeny, Martin P.
AU - Svec, Walter A.
AU - Wasielewski, Michael R
PY - 1996
Y1 - 1996
N2 - The electric field photogenerated by an electron donor-acceptor pair is probed with a covalently attached dye molecule using transient absorption spectroscopy. The donor molecule, 4-X-naphthalene-1,8-dicarboximide (Dx) (where X is (1) piperidine or (2) pyrrolidine), is directly attached to the 1,4,5,8-naphthalenetetracarboxydiimide acceptor (A), which is attached through a benzene spacer to the probe molecule, 4,4-difluoro-3,5-dimethyl-4-bora-3a, 4a-diaza-s-indacene (P). A ~150fs laser pulse at 412nm selectively excites Dx. The transition dipole of P is approximately perpendicular to the direction of the electric field generated by DX-A~, minimizing the rate of excitation energy transfer from DJ to P, whereas the maximum change in the state dipole upon excitation is parallel to the electric field, maximizing Stark-shift effects. The groundstate absorption spectrum of P in 1,4-dioxane (Ama)( = 512 nm) blue-shifts 5 + 1 nm and bleaches as the nearby radical pair (DX-A~) forms. The band-shift effect diminishes in the higher polarity solvents tetrahydrofuran and butyronitrile but does not disappear completely. Solvatochromism measurements performed at room temperature and conventional electrochromism measurements performed at 77 K on P alone, indicate that the state dipole of P decreases by 2.0+0.2 D upon excitation to the first excited singlet state. From this change in dipole moment and the observed band-shift in DX-A-P, the effective electric field due to the charge-separated pair, experienced by P in 1,4-dioxane, is found to be 6±1 MV/cm. '
AB - The electric field photogenerated by an electron donor-acceptor pair is probed with a covalently attached dye molecule using transient absorption spectroscopy. The donor molecule, 4-X-naphthalene-1,8-dicarboximide (Dx) (where X is (1) piperidine or (2) pyrrolidine), is directly attached to the 1,4,5,8-naphthalenetetracarboxydiimide acceptor (A), which is attached through a benzene spacer to the probe molecule, 4,4-difluoro-3,5-dimethyl-4-bora-3a, 4a-diaza-s-indacene (P). A ~150fs laser pulse at 412nm selectively excites Dx. The transition dipole of P is approximately perpendicular to the direction of the electric field generated by DX-A~, minimizing the rate of excitation energy transfer from DJ to P, whereas the maximum change in the state dipole upon excitation is parallel to the electric field, maximizing Stark-shift effects. The groundstate absorption spectrum of P in 1,4-dioxane (Ama)( = 512 nm) blue-shifts 5 + 1 nm and bleaches as the nearby radical pair (DX-A~) forms. The band-shift effect diminishes in the higher polarity solvents tetrahydrofuran and butyronitrile but does not disappear completely. Solvatochromism measurements performed at room temperature and conventional electrochromism measurements performed at 77 K on P alone, indicate that the state dipole of P decreases by 2.0+0.2 D upon excitation to the first excited singlet state. From this change in dipole moment and the observed band-shift in DX-A-P, the effective electric field due to the charge-separated pair, experienced by P in 1,4-dioxane, is found to be 6±1 MV/cm. '
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M3 - Article
VL - 20
SP - 815
EP - 828
JO - New Journal of Chemistry
JF - New Journal of Chemistry
SN - 1144-0546
IS - 7-8
ER -