A study of negative ions from substituted benzils

The mass spectra and the appearance potentials for the negative ions from a number of 4‐substituted and 4,4′‐disubstituted benzils, containing CH3, CH3O, CH3S, (CH3)2N and NO2 substituents have been measured. Molecular anions were observed for all benzils. The negative ion mass spectra of the CH3O‐ and CH3S‐substituted compounds also exhibited ions resulting from loss of CH3 from the parent; Cl− was observed too in the spectra of the chlorine substituted benzils. Only for the nitrobenzils is more than one fragment ion observed in the spectra. A comparison of the negative ion spectra with the positive ion spectra previously reported is also presented and discussed.