The electron impact mass spectra of salicylaldoxime, 2-hydroxyacetophenone oxime, 2-hydroxybenzophenone oxime, 2-hydroxy-4-methoxybenzophenone oxime and bisarom. hydroxyloxime metal (Cu(II), Ni(II), Co(II and Fe(II)) complexes were studied using high resoln. mass spectrometry, metastable ion measurements and the stable isotopes 15N, 63Cu and 65Cu labeling to elucidate the fragmentation pathways. The spectra of all compounds except the Fe-complex show mol. ions. The relative intensity of mol. ions of complexes is related to the electronic nature of substituents. In all metal complexes the main decomposition pathways involve the successive loss of O, NO and then H2O or LH. In these spectra the fragment ions of metal free species resulting from the cleavage of the dioxime ligands can be discriminated.

Key words: NITROGEN, COPPER, MASS SPECTROGRAPHY, LABELLED COMPOUNDS, IRON COMPLEX, COPPER COMPLEX, STRUCTURAL ANALYSIS, OXIME, COBALT COMPLEX, TRANSITION METAL COMPLEX