Spectres de masse de phosphonates diméthyliques dérivés du norbornane,du norbornéne et du nortricyclane

The mass spectra of dimethyl phosphonates (I to X) derived from norbornane, norbornene and nortricyclene have been studied. The fragmentation of endo and exo isomers is quite similar (only the peak intensities vary a little) except for the saturated compounds I and II where the orientation of the P(O)(OCH₃)₂ group seems to exert an influence. The spectra of the norbornene derivatives III and IV and of the isomeric nortricyclic compound IX are quite different. The fragmentation pattern of all phosphonates I to X is dominated by the localisation of the charge on the phosphorus moiety.