Thermally and electron‐impact‐induced rearrangements of dimethylthioncarbamates in gaseous phase

The thermally and electron‐impact‐induced rearrangements of the dimethylthioncarbamates to the dimethylthiolcarbamates are discussed. Owing to the competition with the ion fragmentation reactions in the mass spectrometric time, < 10 −6 seconds, the extent of the mass spectrometrically observed ion isomerization cannot be predicted from that of the thermal induced one. In the ion fragmentations of the non‐rearranged molecular ions, it was found that the relative abundance of the ion (CH 3 ) 2 NCO ⊕ to the total ionization is larger than that of the ion (CH 3 ) 2 NCS ⊕ . This is believed to be attributable to the differences in the dissociation energies of the CS bond and the CO bond and in the stabilities of the two ions.