Singlet state rearrangement/elimination

It is important to note that for methyl nitrenium ion the singlet state is not predicted at higher levels of theory to show a potential energy minimum. Rather this species is a transition structure that eliminates H2 without a barrier (Fig. 13.15). It seems likely that the difficulties encountered in attempting to study alkyl nitrenium ions might be traced to their propensity to rearrange or eliminate. 

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