Electron impact induced fragmentation of dibenzo-18-crown-6 polyether and its nitro derivatives

The mass spectra of dibenzo-18-crown-6 polyether and three of its nitro derivatives have been determined. The fragmentation pathways of all the compounds suggested that ring contraction was taking place. The molecular ion of the polyether dissociated by three competing processes, mainly through loss of C₂H₄O units. The molecular ions of the three derivatives dissociated with ring contraction, as well as through losses of O, No and NO₂.