Mass spectral investigations on selenium compounds. II. The behaviour of meta-and para-substituted benzeneseleninic acids and of meta-nitrophenyl selenocyanate under electron impact

Abstract

Substituted benzeneseleninic acids of the type XC₆H₄SeO₂H (X = m-Cl, p-Cl, m-Br, p-Br, p-Me, m-NO₂, p-NO₂) have been investigated by mass spectrometry. The fragmentation modes and the fragment ions are discussed and compared with those obtained from the mass spectrum of m-nitro-phenyl selenocyanate, O₂NC₆H₄SeCN. Generally, as regards the acids, besides very weak peaks due to the molecular ions, a number of peaks at higher mass numbers and of greater intensity is observed; these peaks are in multiplets typical of the presence of two selenium atoms, and they correspond to the disubstituted diphenyl diselenides of the type XC₆H₄SeSeC₆H₄X. m-Nitrophenyl selenocyanate shows an intense molecular ion peak and the relative fragmentation, while the peak due to the diselenide is of very low intensity.