Time-resolved energy-dispersive XAS studies of photoinduced electron transfer intermediates in electron donor-acceptor complexes

Lin X. Chen, Peter L. Lee, David Gosztola, Walter A. Svec, Michael R Wasielewski

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

The structure around the Fe atom of a photoinduced electron transfer intermediate in a di-porphyrin electron donor/acceptor complex is studied with time-resolved energy dispersive X-ray absorption spectroscopy. Photoinduced electron transfer from the lowest excited triplet state of a Zn porphyrin attached at a fixed 25 D distance by means of a long spacer molecule to an Fe(III) porphyrin occurs with a 6 ms time constant at 77 K. Time domain X-ray absorption measurements show that Fe(III) is transiently photoreduced to Fe(II) and that the bond between the Fe atom and a pyridine molecule ligated to it weakens substantially upon reduction of the Fe. Coupling of ligand loss to reduction of Fe(III) to Fe(II) provides a mean of stabilizing the reduced intermediate.

Original languageEnglish
Pages (from-to)403-405
Number of pages3
JournalJournal of Synchrotron Radiation
Volume6
Issue number3
Publication statusPublished - May 1 1999

Fingerprint

Porphyrins
porphyrins
electron transfer
Electrons
Atoms
X ray absorption spectroscopy
Molecules
electrons
X ray absorption
Excited states
Pyridine
spacers
atomic energy levels
time constant
atoms
energy
molecules
pyridines
absorption spectroscopy
x rays

Keywords

  • Energy dispersive XAS
  • Photoinduced electron transfer
  • Porphyrin complexes
  • Time-resolved XAFS
  • XANES

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)
  • Instrumentation
  • Atomic and Molecular Physics, and Optics
  • Radiation

Cite this

Time-resolved energy-dispersive XAS studies of photoinduced electron transfer intermediates in electron donor-acceptor complexes. / Chen, Lin X.; Lee, Peter L.; Gosztola, David; Svec, Walter A.; Wasielewski, Michael R.

In: Journal of Synchrotron Radiation, Vol. 6, No. 3, 01.05.1999, p. 403-405.

Research output: Contribution to journalArticle

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AU - Wasielewski, Michael R

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AB - The structure around the Fe atom of a photoinduced electron transfer intermediate in a di-porphyrin electron donor/acceptor complex is studied with time-resolved energy dispersive X-ray absorption spectroscopy. Photoinduced electron transfer from the lowest excited triplet state of a Zn porphyrin attached at a fixed 25 D distance by means of a long spacer molecule to an Fe(III) porphyrin occurs with a 6 ms time constant at 77 K. Time domain X-ray absorption measurements show that Fe(III) is transiently photoreduced to Fe(II) and that the bond between the Fe atom and a pyridine molecule ligated to it weakens substantially upon reduction of the Fe. Coupling of ligand loss to reduction of Fe(III) to Fe(II) provides a mean of stabilizing the reduced intermediate.

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