Protonated Methane Ions and their Analogs

Multiply-Protonated Methane Ions and their Analogs In addition to the involvement in a single 3c-2e bond formation, carbon is also capable of simultaneously participating in two 3c-2e bonds in some carbodications. Diprotonated methane (protiomethonium dication, C l P ) is the parent of such carbodications. 

Quantum mechanical calculations (by ab initio method) performed on diprotonated methane showed that the symmetrical structure (18) with two stabilizing orthogonal 3c-2e interactions is the only minimum on the potential energy surface. The other structures (19-22), in turn, were calculated to be saddle points on the potential energy surface. These were found to be 

Other six-coordinate carbon-containing carbocations reported so far are the (23) and the CLie dication (24). Ion 23 was observed by 

Hogeveen and Kwant and has a pyramidal structure (see Section 5.6.2). According to calculations carried out for CLie (24), an octahedral structure is preferred. Furthermore, similar to the five-coordinate CH5 analog gold complexes, Schmidbaur et have also prepared and character- 

As calculations showed, protonation of BH, to form BI 1 is highly exothermic by 154.4kcalmol , which is even more exothermic by 26.4kcalmoT than the protonation of methane. These data suggest that in a previous study, when Olah et al. investigated the protonation of BIB to obtain evidence 

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