Cluster Ions in the Electron and Chemical Ionization Mass Spectra of Transition-Metal Acetylacetonates

The electron ionization mass spectra of transition-metal acetylacetonates have been recorded under conditions that maximize the abundance of cluster ions (those ions containing two or more metal atoms). Present electron ionization results obtained for copper(II), iron(III), and vanadium(III) acetylacetonates are similar to previously reported results for ions smaller than the molecular ion, but several new cluster ions of higher mass are observed. Cluster ions for zirconium(IV) and palladium(II) acetylacetonates under electron ionization conditions are reported here for the first time. The methane and ammonia chemical ionization mass spectra of transitiori-metal acetylacetonates are also included in this report; this represents the first application of chemical ionization mass spectrometry to this class of compounds.