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The excited-state chemistry of protochlorophyllide a: A time-resolved fluorescence study

Dietzek, Benjamin ; Kiefer, Wolfgang ; Yartsev, Arkady LU orcid ; Sundström, Villy LU ; Schellenberg, Peter ; Grigaravicius, Paulius ; Hermann, Gudrun ; Popp, Jurgen and Schmitt, Michael (2006) In ChemPhysChem 7(8). p.1727-1733
Abstract
The excited-state processes of protochlorophyllide a, the precursor of chlorophyll a in chlorophyll biosynthesis, are studied using picosecond time-resolved fluorescence spectroscopy. Following excitation into the Soret band, two distinct fluorescence components, with emission maxima at 640 and 647 nm, ore observed. The 640 nm emitting component appears within the time resolution of the experiment and then decays with a time constant of 27 ps. In contrast, the 647 nm emitting component is built up with a 3.5 ps rise time and undergoes a subsequent decay with a time constant of 3.5 ns. The 3.5 ps rise kinetics are attributed to relaxations in the electronically excited state preceding the nanosecond fluorescence, which is ascribed to... (More)
The excited-state processes of protochlorophyllide a, the precursor of chlorophyll a in chlorophyll biosynthesis, are studied using picosecond time-resolved fluorescence spectroscopy. Following excitation into the Soret band, two distinct fluorescence components, with emission maxima at 640 and 647 nm, ore observed. The 640 nm emitting component appears within the time resolution of the experiment and then decays with a time constant of 27 ps. In contrast, the 647 nm emitting component is built up with a 3.5 ps rise time and undergoes a subsequent decay with a time constant of 3.5 ns. The 3.5 ps rise kinetics are attributed to relaxations in the electronically excited state preceding the nanosecond fluorescence, which is ascribed to emission out of the thermally equilibrated S, state. The 27 ps fluorescence, which appears within the experimental response of the streak camera, is suggested to originate from a second minimum on the excited-state potentiol-energy surface. The population of the secondary excited state is suggested to reflect a very fast motion out of the Franck-Condon region along a reaction coordinate different from the one connecting the Franck-Condon region with the S-1 potential-energy minimum. The 27 ps-component is an emissive intermediate on the reactive excited-state pathway, as its decay yields the intermediate photoproduct, which has been identified previously (J. Phys. Chem. B 2006, 110, 4399-4406). No emission of the photoproduct is observed. The results of the time-resolved fluorescence study allow a detailed spectral characterization of the emission of the excited states in protochlorophyllide a, and the refinement of the kinetic model deduced from ultrafast absorption measurements. (Less)
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author
; ; ; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
time-resolved spectroscopy, porphyrins, photochemistry, femtochemistry, fluorescence spectroscopy
in
ChemPhysChem
volume
7
issue
8
pages
1727 - 1733
publisher
John Wiley and Sons
external identifiers
  • wos:000239884300019
  • scopus:33748126163
ISSN
1439-7641
DOI
10.1002/cphc.200600172
language
English
LU publication?
yes
additional info
The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Chemical Physics (S) (011001060)
id
35588bf3-e267-48d0-b48a-d6c9a287b2a9 (old id 397529)
date added to LUP
2016-04-01 12:13:10
date last changed
2021-01-06 06:32:52
@article{35588bf3-e267-48d0-b48a-d6c9a287b2a9,
  abstract     = {The excited-state processes of protochlorophyllide a, the precursor of chlorophyll a in chlorophyll biosynthesis, are studied using picosecond time-resolved fluorescence spectroscopy. Following excitation into the Soret band, two distinct fluorescence components, with emission maxima at 640 and 647 nm, ore observed. The 640 nm emitting component appears within the time resolution of the experiment and then decays with a time constant of 27 ps. In contrast, the 647 nm emitting component is built up with a 3.5 ps rise time and undergoes a subsequent decay with a time constant of 3.5 ns. The 3.5 ps rise kinetics are attributed to relaxations in the electronically excited state preceding the nanosecond fluorescence, which is ascribed to emission out of the thermally equilibrated S, state. The 27 ps fluorescence, which appears within the experimental response of the streak camera, is suggested to originate from a second minimum on the excited-state potentiol-energy surface. The population of the secondary excited state is suggested to reflect a very fast motion out of the Franck-Condon region along a reaction coordinate different from the one connecting the Franck-Condon region with the S-1 potential-energy minimum. The 27 ps-component is an emissive intermediate on the reactive excited-state pathway, as its decay yields the intermediate photoproduct, which has been identified previously (J. Phys. Chem. B 2006, 110, 4399-4406). No emission of the photoproduct is observed. The results of the time-resolved fluorescence study allow a detailed spectral characterization of the emission of the excited states in protochlorophyllide a, and the refinement of the kinetic model deduced from ultrafast absorption measurements.},
  author       = {Dietzek, Benjamin and Kiefer, Wolfgang and Yartsev, Arkady and Sundström, Villy and Schellenberg, Peter and Grigaravicius, Paulius and Hermann, Gudrun and Popp, Jurgen and Schmitt, Michael},
  issn         = {1439-7641},
  language     = {eng},
  number       = {8},
  pages        = {1727--1733},
  publisher    = {John Wiley and Sons},
  series       = {ChemPhysChem},
  title        = {The excited-state chemistry of protochlorophyllide a: A time-resolved fluorescence study},
  url          = {http://dx.doi.org/10.1002/cphc.200600172},
  doi          = {10.1002/cphc.200600172},
  volume       = {7},
  year         = {2006},
}