Time-resolved electron transfer in porphyrin-coordinated ruthenium dimers

From mixed-valence dynamics to hot electron transfer

Jonas Petersson, Jane Henderson, Allison Brown, Leif Hammarström, Clifford P. Kubiak

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Presented here is the first effort to study the formation and dynamics of the triruthenium cluster (Ru3O) pyrazine-bridged dimer mixed-valence state. Femtosecond transient absorption spectroscopy was implemented to follow photoinduced electron-transfer reactions in a series of asymmetric porphyrin-coordinated dyads, which form strongly coupled mixed-valence species upon single reduction. Excitation of the porphyrin subunit resulted in electron transfer to the Ru3O dimer with a time constant τ ≈ 0.6 ps. The intramolecular electron transfer was confirmed by excitation of the Ru3O MLCT, which resulted in the formation of a vibrationally unrelaxed porphyrin ground state. Under both excitation experiments, the back electron transfer was extremely fast (τCR <0.1 ps), preventing complete time-resolved exploration of the mixed-valence state. These complexes enabled the observation of excited product states following electron-transfer processes, resulting from porphyrin S1 and S2 excitation. Although the charge recombination itself could not be observed, the yield of unrelaxed ground states supports the conclusion that delocalization takes place at least partially on a sub-100 fs time scale.

Original languageEnglish
Pages (from-to)4479-4487
Number of pages9
JournalJournal of Physical Chemistry C
Volume119
Issue number9
DOIs
Publication statusPublished - Mar 5 2015

Fingerprint

Ruthenium
Hot electrons
Porphyrins
hot electrons
porphyrins
Dimers
ruthenium
electron transfer
dimers
valence
Electrons
Ground state
excitation
Pyrazines
Absorption spectroscopy
ground state
Electron energy levels
pyrazines
time constant
absorption spectroscopy

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Electronic, Optical and Magnetic Materials
  • Surfaces, Coatings and Films
  • Energy(all)

Cite this

Time-resolved electron transfer in porphyrin-coordinated ruthenium dimers : From mixed-valence dynamics to hot electron transfer. / Petersson, Jonas; Henderson, Jane; Brown, Allison; Hammarström, Leif; Kubiak, Clifford P.

In: Journal of Physical Chemistry C, Vol. 119, No. 9, 05.03.2015, p. 4479-4487.

Research output: Contribution to journalArticle

Petersson, Jonas ; Henderson, Jane ; Brown, Allison ; Hammarström, Leif ; Kubiak, Clifford P. / Time-resolved electron transfer in porphyrin-coordinated ruthenium dimers : From mixed-valence dynamics to hot electron transfer. In: Journal of Physical Chemistry C. 2015 ; Vol. 119, No. 9. pp. 4479-4487.
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