Thio derivatives of β-Diketones and their metal chelates. XV. Mass spectra of cobalt(III) and rhodium(III) chelates of some fluorinated Monothio-β-diketones

Abstract

The mass spectra of the cobalt(111) and rhodium(111) chelates of the fluorinated monothio-β-diketones RC(SH)=CHCOCF₃ (R = Ph, p-MeC₆H₄, p-BrC₆H₄, p-FC₆H₄, and 2-thienyl) and of the cobalt(111) chelate of CH₃C(SH)=CHCOCF₃ have been obtained. The cobalt chelates do not give a peak for the molecular ion because of thermal degradation to the cobalt(11) complex CO(RCS=CHCOCF₃)₂, which then undergoes reactions in the mass spectrometer. Fluorine migration occurs with cobalt but not with rhodium. The cobalt complexes give rise to more metal-containing fragments than their rhodium analogues. Mechanisms are proposed for the reactions involving the metal-containing fragments. Cobalt undergoes valency changes to give cobalt(11) and cobalt(1) complex ions, whereas rhodium undergoes a valency change to the bivalent state only.