Intracluster cyclization reaction producing a benzene derivative: Photoionization mass spectrometric study of alkali metal-methyl propiolate clusters

Hironori Tsunoyama, Keijiro Ohshimo, Fuminori Misaizu, Koichi Ohno

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1 Citation (Scopus)


Size-dependent stability and intracluster reactions have been investigated by photoionization mass spectrometry for alkali metal (M; Li, Na, and K)-methyl propiolate (MP; HC≡CCOOCH3) molecules clusters. In the photoionization mass spectra, the intensities of M+(MP)3 ions (M=Na and K) were unexpectedly high, whereas no intensity anomaly was observed in Li+(MP)n mass spectrum. The intensity anomaly can be explained by intracluster cyclization reaction induced by electron transfer from the metal atom and resulting a stable benzene derivative formation. Ion intensities of M+(MP)n(H2O) relative to M+(MP)n have a minimum at n=3 in Na and K systems. This result is owing to evaporation of water and/or MP molecules following exothermic cyclization reaction. Fragment ions with a loss of CH 2 were also observed predominantly from M(MP)2 in all metal systems. These ions are expected to be produced by hydrolysis in M(MP)n(H2O) clusters producing a HC≡CCOOH molecule. The difference between lithium and other alkali metals is due to the rigidity of clusters with respect to deformation into geometry leading to the polymerization reaction.

Original languageEnglish
Pages (from-to)41-50
Number of pages10
JournalInternational Journal of Mass Spectrometry
Issue number1
Publication statusPublished - 2004 Mar 1



  • Alkali metal
  • Cyclization
  • Intracluster reaction
  • Photoionization
  • Polymerization

ASJC Scopus subject areas

  • Instrumentation
  • Condensed Matter Physics
  • Spectroscopy
  • Physical and Theoretical Chemistry

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