Structure Formation and Coupling Reactions of Hexaphenylbenzene and Its Brominated Analog

Authors

Jacob D. Teeter, University of Nebraska – Lincoln
Paulo S. Costa, University of Nebraska – Lincoln
Christoph Dobner, Universität Bayreuth
Mamun Sarker, University of Nebraska-LincolnFollow
Alexander Sinitskii, University of Nebraska-LincolnFollow
A Enders, University of Nebraska-LincolnFollow

Date of this Version

4-27-2021

Citation

ChemPhysChem 2021, 22, 1769– 1773. doi.org/10.1002/cphc.202100049

Comments

© 2021 The Authors. ChemPhysChem published by Wiley-VCH GmbH. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Abstract

The on-surface coupling of the prototypical precursor molecule for graphene nanoribbon synthesis, 6,11-dibromo-1,2,3,4-tetraphenyltriphenylene (C₄₂Br₂H₂₆, TPTP), and its non-brominated analog hexaphenylbenzene (C₄₂H₃₀, HPB), was investigated on coinage metal substrates as a function of thermal treatment. For HPB, which forms non-covalent 2D monolayers at room temperature, a thermally induced transition of the monolayer’s structure could be achieved by moderate annealing, which is likely driven by π-bond formation. It is found that the dibrominated carbon positions of TPTP do not guide the coupling if the growth occurs on a substrate at temperatures that are sufficient to initiate C--H bond activation. Instead, similar one-dimensional molecular structures are obtained for both types of precursors, HPB and TPTP.