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Correlations of chemical mass shifts of para-substituted acetophenones and benzophenones with brown’s σ p + constants

  • Yanan Peng
  • Wolfgang R. Plass
  • R. Graham Cooks
Focus: Quadrupole Ion Traps

Abstract

Relationships between chemical mass shifts and physiochemical properties of ions are sought by examining substituted acetophenones, benzophenones, and pyridines in a modified ion trap mass spectrometer. Systematic changes in chemical mass shift occur with changes in substituent in the acetophenones and the benzophenones. Brown’s σ+ constant, which is a measure of electronic effects of substituents in reactions that involve positive charge development, is shown to correlate linearly with chemical mass shifts in para-substituted acetophenones and benzophenones. Brown’s σ+ constant also correlates with the ease of dissociation of the ions via a correlation with ionization energy. It is suggested that ease of dissociation is the underlying factor in determining chemical mass shifts. The experimental results also suggest that dissociative collisions between ions and buffer gas make a much greater contribution to chemical mass shifts than do elastic collisions.

Keywords

Acetophenones Benzophenone Mass Shift Substituent Effect Chemical Mass Shift 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© American Society for Mass Spectrometry 2002

Authors and Affiliations

  • Yanan Peng
    • 1
  • Wolfgang R. Plass
    • 1
  • R. Graham Cooks
    • 1
  1. 1.Department of ChemistryPurdue UniversityWest LafayetteUSA

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