Is the [9]Annulene Cation a Möbius Annulene?

Does it do the twist? High-level theoretical calculations show that the [9]annulene cation exists in two isomers: a twisted 4n electron Möbius aromatic compound, and a non-twisted boat-like Hückel conformation (see scheme). The latter form was detected by laser flash photolysis experiments; an example of a stable, charged, or uncharged parent Möbius annulene is still elusive. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.