Thio derivatives of b-diketones and their metal chelates. XIII. Mass spectra of zinc and nickel chelates of some fluorinated monothio-b-diketones

Abstract

The mass spectra of the zinc(11) and nickel(11) chelates of four fluorinated monothio-β-diketones, RC(SH)=CHCOCF₃ (R = Ph, p-MeC₆H₄, 2-thienyl, Me), have been obtained. The mass spectra of the nickel chelates have considerably more peaks due to metal-containing species than the spectra of the zinc chelates, while the reverse is true for the metal-free fragments. All the zinc chelates give peaks for M (molecular ion), M ? CF₃, M - L (LH = monothio-β-diketone), M - L ? CF₂, LH, L, L - F, RCSCH and RCS. All the nickel chelates give peaks for M, M - F, M ? CF₃, M - COCF₃, M - L, M- 2L and L. In addition, some of the metal chelates give other peaks. Mechanisms are proposed for the reactions giving rise to some of these species. All the zinc and nickel chelates give a strong peak due to L⁺ arising from a valence change of the metal ion from the bivalent to the univalent state as follows: [Me¹¹L₂]⁺ → L⁺ + Me¹L (Me = Zn, Ni). It is suggested that the ion L⁺ has a resonance-stabilized cyclic structure.