%0 Journal Article
%A Haags, Anja
%A Reichmann, Alexander
%A Fan, Qitang
%A Egger, Larissa
%A Kirschner, Hans
%A Naumann, Tim
%A Werner, Simon
%A Vollgraff, Tobias
%A Sundermeyer, Jörg
%A Eschmann, Lukas
%A Yang, Xiaosheng
%A Brandstetter, Dominik
%A Posseik, Francois
%A Koller, Georg
%A Gottwald, Alexander
%A Richter, Mathias
%A Ramsey, Michael G.
%A Rohlfing, Michael
%A Puschnig, Peter
%A Gottfried, J. Michael
%A Soubatch, Serguei
%A Tautz, F. Stefan
%T Kekulene: On-Surface Synthesis, Orbital Structure, and Aromatic Stabilization
%J ACS nano
%V 14
%N 11
%@ 1936-086X
%C Washington, DC
%I Soc.
%M FZJ-2021-03370
%P 15766 - 15775
%D 2020
%X We revisit the question of kekulene’s aromaticity by focusing on the electronic structure of its frontier orbitals as determined by angle-resolved photoemission spectroscopy. To this end, we have developed a specially designed precursor, 1,4,7(2,7)-triphenanthrenacyclononaphane-2,5,8-triene, which allows us to prepare sufficient quantities of kekulene of high purity directly on a Cu(111) surface, as confirmed by scanning tunneling microscopy. Supported by density functional calculations, we determine the orbital structure of kekulene’s highest occupied molecular orbital by photoemission tomography. In agreement with a recent aromaticity assessment of kekulene based solely on C–C bond lengths, we conclude that the π-conjugation of kekulene is better described by the Clar model rather than a superaromatic model. Thus, by exploiting the capabilities of photoemission tomography, we shed light on the question which consequences aromaticity holds for the frontier electronic structure of a π-conjugated molecule.
%F PUB:(DE-HGF)16
%9 Journal Article
%$ 33186031
%U <Go to ISI:>//WOS:000595533800118
%R 10.1021/acsnano.0c06798
%U https://juser.fz-juelich.de/record/894718