Exciplex formation of copper(II) octaethylporphyrin revealed by pulsed X-rays

Lin X. Chen*, George B. Shaw, Tao Liu, Guy Jennings, Klaus Attenkofer

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

23 Scopus citations

Abstract

The triplet excited structures of Cu(II) octaethylporphyrin (CuOEP) in toluene and in 1:1 mixture of toluene and tetrahydrofuran (THF) were investigated by time-domain laser pulse pump, X-ray pulse probe X-ray absorption spectroscopy (pump-probe XAS) at room temperature using X-rays from a third generation synchrotron source with 100-ps time resolution. The transient optical absorption measurements indicate a strong solvent dependency of the triplet excited state lifetime due to the presence of oxygen-containing solvent molecules. While the ground state CuOEP molecules remain square-planar in both solvents, the attenuation of a peak attributed to the 1s→4p z transition at the Cu K-edge for the laser excited CuOEP in the THF/toluene mixture revealed the penta-coordinated exciplex formation which is responsible for the shortening of the triplet excited state lifetime. Meanwhile, the average Cu-N distance in the triplet excited state is lengthened by 0.03 Å due to ligation with a THF solvent molecule, which agrees with a domed coordination structure for copper in the penta-coordinated exciplex.

Original languageEnglish (US)
Pages (from-to)215-223
Number of pages9
JournalChemical Physics
Volume299
Issue number2-3
DOIs
StatePublished - Apr 19 2004

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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