Proponium ions isomeric

Figure 11. Different ways for the formation of the isomeric proponium ions.

Two isomeric proponium ions, cation 455 and 457 were computed by Collins and O Malley831 (DFTand MP2 calculations). The 2-//-protonated cation 456, in turn, was suggested to be rather the transition state for the interconversion of the ions. Structure 456 is better described as the van der Waals complex of, vec-C3H7+ and H2, which was already suggested by Hiraoka and Kebarle.748 Mota and co-workers832 have recently... 

The formation of C-ethanemethonium can occur by protoiytic attack of C-H or C-C bonds, leading to H-proponium or C-proponium pentacoordinated ions, respectively. Proponium ions can further evolve towards isomeric C-ethanemethonium ion via bond-bond rearrangement. The nature of the initial interaction between proton and propane molecule is of little importance because intramolecular reatrangements of energetically close carbonium ion forms take place easily [26]. 

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