Gitonic and distonic alkanonium dications (diprotonated alkane dications CnH2n+42+, n=1-4)

The structures and stabilities of gitonic and distonic alkanonium dications, i.e., diprotonated alkane dications CnH2n+42+ (n = 1-4), were investigated at the MP4(SDTQ)/6-311G**//MP2/6-31G** level. The global minimum energy structures (2, 4, 7, and 10) of the CnH2n+42+ dications are double C-H protonated alkanes to give structures with two two electron three-center (2e-3c) bonds. Two different dissociation pathways for the dications, viz deprotonation and demethylation, were also computed. Demethylation was found to be the favorable mode of dissociation.