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On‐Surface Synthesis of Cumulene‐Containing Polymers via Two‐Step Dehalogenative Homocoupling of Dibromomethylene‐Functionalized Tribenzoazulene
Author(s) -
Urgel José I.,
Di Giovannantonio Marco,
Eimre Kristjan,
Lohr Thorsten G.,
Liu Junzhi,
Mishra Shantanu,
Sun Qiang,
Kinikar Amogh,
Widmer Roland,
Stolz Samuel,
Bommert Max,
Berger Reinhard,
Ruffieux Pascal,
Pignedoli Carlo A.,
Müllen Klaus,
Feng Xinliang,
Fasel Roman
Publication year - 2020
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.202001939
Subject(s) - cumulene , polymer , x ray photoelectron spectroscopy , double bond , surface modification , materials science , reactivity (psychology) , chemistry , polymer chemistry , molecule , nanotechnology , chemical engineering , organic chemistry , medicine , alternative medicine , pathology , engineering
Cumulene compounds are notoriously difficult to prepare and study because their reactivity increases dramatically with the increasing number of consecutive double bonds. In this respect, the emerging field of on‐surface synthesis provides exceptional opportunities because it relies on reactions on clean metal substrates under well‐controlled ultrahigh‐vacuum conditions. Here we report the on‐surface synthesis of a polymer linked by cumulene‐like bonds on a Au(111) surface via sequential thermally activated dehalogenative C−C coupling of a tribenzoazulene precursor equipped with two dibromomethylene groups. The structure and electronic properties of the resulting polymer with cumulene‐like pentagon–pentagon and heptagon–heptagon connections have been investigated by means of scanning probe microscopy and spectroscopy methods and X‐ray photoelectron spectroscopy, complemented by density functional theory calculations. Our results provide perspectives for the on‐surface synthesis of cumulene‐containing compounds, as well as protocols relevant to the stepwise fabrication of carbon–carbon bonds on surfaces.