APPLICATION OF INTEGRATED ION-CURRENT TECHNIQUE TO STUDY OF RARE-EARTH CHELATES

Several substituted acetylacetones have been prepared and reacted with holmium to give tris chelates of the form HoL3. One of these chelates has been converted to a tetrakis chelate of the form NaHoL4. The mass spectra of these compounds have been studied and the integrated ion currents at significant m/e values have been related to the amounts of metal chelates evaporated into the ion source of the mass spectrometer. The shape of the integrated ion-current curve is shown to give information about the nature of the evaporation process. When the β-diketone (L) is asymmetrical as in the case of 1,1,1-trifluoro-5,5-dimethylhexan-2,4-dione, the existence of geometrical isomers of the chelate, HoL3, is reflected in the shape of the integrated ion-current curve, which shows fine structure. The results of mass spectrometric studies are compared with those of the sublimation and gas chromatographic behaviour of the metal chelates. © 1968.