On-Surface Annulation Reaction Cascade for the Selective Synthesis of Diindenopyrene
F. Eisenhut, T. Lehmann, A. Viertel, D. Skidin, J. Krüger, S. Nikipar, D. A. Ryndyk, C. Joachim, S. Hecht, F. Moresco, G. Cuniberti
ACS Nano 11, 12419 (2017)
We investigated the thermally induced on-surface cyclization of 4,10-bis(2’-bromo-4’-methylphenyl)-1,3-dimethylpyrene to form the previously unknown, non-alternant polyaromatic hydrocarbon diindeno[1,2,3-cd:1´,2´,3´-mn]pyrene on Au(111) using scanning tunneling microscopy and spectroscopy. The observed unimolecular reaction involves thermally induced debromination followed by selective ring-closure to fuse the neighboring benzene moieties via a five-membered ring. The structure of the product has been verified experimentally as well as theoretically. Our results demonstrate that on-surface reactions give rise to unusual chemical reactivities and selectivities and provide access to new molecules.