Electric field effects of photogenerated ion pairs on nearby molecules

A model for the carotenoid band shift in photosynthesis

David Gosztola, Hiroko Yamada, Michael R Wasielewski

Research output: Contribution to journalArticle

50 Citations (Scopus)

Abstract

Photoinduced charge separation within a zinc porphyrin electron donor-pyromellitimide electron acceptor pair possessing an 8.4 Å center-to-center distance and a linear orientation is shown to induce large electrochromic effects on the ground state absorption spectrum of a nearby carotenoid molecule. The orientation of the C-C backbone of the carotenoid is restricted relative to the direction of the electric field produced by the photogenerated ion pair. This is accomplished by covalently linking the electron donor - acceptor pair to the carotenoid with a calix[4]arene bridge. The bridge maintains its cone conformation resulting in an average dihedral angle of 35° between the donor-acceptor axis and the C-C backbone of the carotenoid. Using picosecond transient absorption spectroscopy, a 15 nm electrochromic red shift in the ground state absorption spectrum of the carotenoid was readily observed during the 3.7 ns lifetime of the photogenerated ion pair. The magnitude of this shift depends on the dielectric constant of the surrounding solvent. The data is used to calculate an electric field strength of about 5.5 MV/cm at the carotenoid in toluene. The magnitude of the electric field produced by the ion pair at the carotenoid is larger than the highest fields that can be applied externally. This approach can be used to study the influence of electric fields produced by ion pairs on the photophysics and photochemistry of nearby molecules.

Original languageEnglish
Pages (from-to)2041-2048
Number of pages8
JournalJournal of the American Chemical Society
Volume117
Issue number7
Publication statusPublished - Feb 22 1995

Fingerprint

Electric field effects
Photosynthesis
Carotenoids
Ions
Molecules
Electric fields
Electrons
Ground state
Absorption spectra
Photochemistry
Photochemical reactions
Porphyrins
Toluene
Dihedral angle
Absorption spectroscopy
Conformations
Cones
Spectrum Analysis
Zinc
Permittivity

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

Electric field effects of photogenerated ion pairs on nearby molecules : A model for the carotenoid band shift in photosynthesis. / Gosztola, David; Yamada, Hiroko; Wasielewski, Michael R.

In: Journal of the American Chemical Society, Vol. 117, No. 7, 22.02.1995, p. 2041-2048.

Research output: Contribution to journalArticle

@article{0a8362d4dd9549489ab7c6ec94b27f01,
title = "Electric field effects of photogenerated ion pairs on nearby molecules: A model for the carotenoid band shift in photosynthesis",
abstract = "Photoinduced charge separation within a zinc porphyrin electron donor-pyromellitimide electron acceptor pair possessing an 8.4 {\AA} center-to-center distance and a linear orientation is shown to induce large electrochromic effects on the ground state absorption spectrum of a nearby carotenoid molecule. The orientation of the C-C backbone of the carotenoid is restricted relative to the direction of the electric field produced by the photogenerated ion pair. This is accomplished by covalently linking the electron donor - acceptor pair to the carotenoid with a calix[4]arene bridge. The bridge maintains its cone conformation resulting in an average dihedral angle of 35° between the donor-acceptor axis and the C-C backbone of the carotenoid. Using picosecond transient absorption spectroscopy, a 15 nm electrochromic red shift in the ground state absorption spectrum of the carotenoid was readily observed during the 3.7 ns lifetime of the photogenerated ion pair. The magnitude of this shift depends on the dielectric constant of the surrounding solvent. The data is used to calculate an electric field strength of about 5.5 MV/cm at the carotenoid in toluene. The magnitude of the electric field produced by the ion pair at the carotenoid is larger than the highest fields that can be applied externally. This approach can be used to study the influence of electric fields produced by ion pairs on the photophysics and photochemistry of nearby molecules.",
author = "David Gosztola and Hiroko Yamada and Wasielewski, {Michael R}",
year = "1995",
month = "2",
day = "22",
language = "English",
volume = "117",
pages = "2041--2048",
journal = "Journal of the American Chemical Society",
issn = "0002-7863",
publisher = "American Chemical Society",
number = "7",

}

TY - JOUR

T1 - Electric field effects of photogenerated ion pairs on nearby molecules

T2 - A model for the carotenoid band shift in photosynthesis

AU - Gosztola, David

AU - Yamada, Hiroko

AU - Wasielewski, Michael R

PY - 1995/2/22

Y1 - 1995/2/22

N2 - Photoinduced charge separation within a zinc porphyrin electron donor-pyromellitimide electron acceptor pair possessing an 8.4 Å center-to-center distance and a linear orientation is shown to induce large electrochromic effects on the ground state absorption spectrum of a nearby carotenoid molecule. The orientation of the C-C backbone of the carotenoid is restricted relative to the direction of the electric field produced by the photogenerated ion pair. This is accomplished by covalently linking the electron donor - acceptor pair to the carotenoid with a calix[4]arene bridge. The bridge maintains its cone conformation resulting in an average dihedral angle of 35° between the donor-acceptor axis and the C-C backbone of the carotenoid. Using picosecond transient absorption spectroscopy, a 15 nm electrochromic red shift in the ground state absorption spectrum of the carotenoid was readily observed during the 3.7 ns lifetime of the photogenerated ion pair. The magnitude of this shift depends on the dielectric constant of the surrounding solvent. The data is used to calculate an electric field strength of about 5.5 MV/cm at the carotenoid in toluene. The magnitude of the electric field produced by the ion pair at the carotenoid is larger than the highest fields that can be applied externally. This approach can be used to study the influence of electric fields produced by ion pairs on the photophysics and photochemistry of nearby molecules.

AB - Photoinduced charge separation within a zinc porphyrin electron donor-pyromellitimide electron acceptor pair possessing an 8.4 Å center-to-center distance and a linear orientation is shown to induce large electrochromic effects on the ground state absorption spectrum of a nearby carotenoid molecule. The orientation of the C-C backbone of the carotenoid is restricted relative to the direction of the electric field produced by the photogenerated ion pair. This is accomplished by covalently linking the electron donor - acceptor pair to the carotenoid with a calix[4]arene bridge. The bridge maintains its cone conformation resulting in an average dihedral angle of 35° between the donor-acceptor axis and the C-C backbone of the carotenoid. Using picosecond transient absorption spectroscopy, a 15 nm electrochromic red shift in the ground state absorption spectrum of the carotenoid was readily observed during the 3.7 ns lifetime of the photogenerated ion pair. The magnitude of this shift depends on the dielectric constant of the surrounding solvent. The data is used to calculate an electric field strength of about 5.5 MV/cm at the carotenoid in toluene. The magnitude of the electric field produced by the ion pair at the carotenoid is larger than the highest fields that can be applied externally. This approach can be used to study the influence of electric fields produced by ion pairs on the photophysics and photochemistry of nearby molecules.

UR - http://www.scopus.com/inward/record.url?scp=0029253524&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0029253524&partnerID=8YFLogxK

M3 - Article

VL - 117

SP - 2041

EP - 2048

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

SN - 0002-7863

IS - 7

ER -