The Threshold Photoelectron Spectrum of Fulvenone: A Reactive Ketene Derivative in Lignin Valorization

Patrick Hemberger, Zeyou Pan, Andras Bodi, Jeroen A. van Bokhoven, Thomas K. Ormond, G. Barney Ellison, Nadav Genossar, Joshua H. Baraban

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

Unveiling reaction mechanisms by isomer-selective detection of reactive intermediates requires advanced spectroscopic knowledge. We study the photoionization of fulvenone (c-C5H4=C=O), a reactive ketene species relevant in catalytic pyrolysis of lignin, which was generated by pyrolysis of 2-methoxy acetophenone. The high-resolution threshold photoelectron spectrum (TPES) with vacuum ultraviolet synchrotron radiation revealed well-resolved vibrational transitions, assigned to ring deformation modes of the cyclopentadiene moiety. The adiabatic ionization energy was determined to be 8.25±0.01 eV and is assigned to the (Formula presented.) 2A2← (Formula presented.) 1A1 transition. A broad and featureless band arising at 9 eV is associated with the (Formula presented.) 2B1← (Formula presented.) 1A1 excitation. A conical intersection is responsible for the ultrafast relaxation of the fulvenone cation from the (Formula presented.) into the (Formula presented.) state resulting in a featureless and lifetime broadened band. These insights will increase the detection capabilities for fulvenone and thereby help to elucidate reaction mechanisms in lignin catalytic pyrolysis.

Original languageEnglish
Pages (from-to)2217-2222
Number of pages6
JournalChemPhysChem
Volume21
Issue number19
DOIs
StatePublished - 2 Oct 2020

Keywords

  • Catalysis
  • ketene
  • lignin
  • photoelectron spectroscopy
  • reactive intermediates

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Physical and Theoretical Chemistry

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