The [13]Annulene Cation Is a Stable Mobius Annulene Cation

The isomers of the [n]annulene cation series (n = 13, 17, and 21) were systematically scrutinized by OFT, SCS-MP2, and coupled-cluster methods. Only in the case of the [13]annulene cation the global minimum is clearly a Mobius structure. According to our theoretical predictions, the [13]annulene cation should also be kinetically stable. Thus, the [13]annulene cation is the most promising candidate for the synthesis of a parent Mobius aromatic system among the neutral and cationic annulenes.