abstract
Four decades after the first (and only) reported synthesis of kekulene, this emblematic cycloarene has been obtained again through an improved route involving the construction of a key synthetic intermediate, 5,6,8,9-tetrahydrobenzo[m]tetraphene, by means of a double Diels-Alder reaction between styrene and a versatile benzodiyne synthon. Ultra-high-resolution AFM imaging of single molecules of kekulene and computational calculations provide additional support for a molecular structure with a significant degree of bond localization in accordance with the resonance structure predicted by the Clar model.
keywords
AROMATIC-COMPOUNDS; SPECTROSCOPIC PROPERTIES; CYCLOADDITION REACTIONS; EFFICIENT SYNTHESIS; CYCLOARENES; BENZYNE; SUPERAROMATICITY; CONJUGATION; SYSTEMS; NUMBER
subject category
Chemistry
authors
Pozo, I; Majzik, Z; Pavlicek, N; Melle-Franco, M; Guitian, E; Pena, D; Gross, L; Perez, D
our authors
Manuel Melle-Franco
Principal Researcheracknowledgements
Financial support from the Spanish Agencia Estatal de Investigacion (CTQ2016-78157-R and MAT2016-78293-C6-3-R; AEI/FEDER, UE), Xunta de Galicia (Centro singular de investigaciOn de Galicia accreditation 2016-2019, ED431G/09), the European Union (European Regional Development Fund-ERDF), and the ERC Consolidator Grant AMSEL (682144) as well as from the Portuguese Foundation for Science and Technology (FCT), under the projects PTDC/FIS-NAN/4662/2014, IF/00894/2015, and CICECO -Aveiro Institute of Materials, FCT ref. UID/CTM/50011/2019, is gratefully acknowledged. I.P. thanks Xunta de Galicia and European Union (European Social Fund, ESF) for the award of a predoctoral fellowship. In addition, M.M.-F. would like to thank the Project HPC-EUROPA3 (INFRAIA-2016-1-730897) and the Barcelona Supercomputing Center for computer resources and technical support. This paper is dedicated to Prof. Francois Diederich and to the memory of Prof. Heinz A. Staab.