Collisional studies of some C3H 7O (+) ions

The C3H7O(+) ions of nominal structures 1, 2, 3, and 4, produced by protonation of acetone, propanal, propylene oxide, and oxetan, respectively, have been studied by a variety of collisional techniques. The nominal isomers 2 and 3 give, within experimental error, identical high-energy collision-induced dissociation (CID) mass spectra. In addition, the breakdown graphs for the two isomers obtained from low, variable energy CID are identical, as are the neutrahzation-reionization mass spectra. The results are consistent with a facile isomerization of 3 to 2. By contrast, the ions of nominal structures 1 and 4 are shown by each technique to be distinct stable species in the gas phase. While the differences in the highenergy CID mass spectrum of 4 compared to 2 and 3 are relatively small, these differences are more pronounced in the low-energy CID mass spectra and become very large in the neutralization-reicnization mass spectra.