Thio derivatives of β-diketones and their metal chelates. XVIII. Mass spectra of some metal chelates of the monothio derivatives of benzoylacetone anddibenzoylmethane

Abstract

The mass spectra of the iron(III), cobalt(III), nickel(II) and zinc(II) complexes of the monothio-β-diketones RC(SH)=CHCOPh (R = Me, Ph) have been obtained. The iron and cobalt complexes of 3-mercapto-1-phenylbut- 2-en-1-one (R = Me) do not give a peak for the molecular ion due to thermal degradation to the bivalent metal complex Met(MeCS=CHCOPh)₂ (Met = Fe, Co), which then undergoes reactions similar to those undergone by the nickel and zinc complexes. The most interesting feature of the spectra is the loss of hydrogen sulphide which does not occur with the free ligand or with metal complexes of fluorinated monothio-8-diketones RC(SH)=CHCOCF₃.     The zinc complex of 3-mercapto-1,3-diphenylprop-2-en-1-one (R = Ph) undergoes fragmentation in the mass spectrometer to produce inter alia [ZnC₆H₅]⁺. However, the iron(III), cobalt(III), nickel(II) and palladium(II) complexes undergo thermal degradation in the mass spectrometer but the mass spectra of these four complexes give metal-free ions with m/e greater than m/e for L, due to fragmentation of the ion 2L.