TY - JOUR
T1 - Hierarchy in the Halogen Activation During Surface-Promoted Ullmann Coupling
AU - Merino-Díez, Néstor
AU - Pérez Paz, Alejandro
AU - Li, Jingcheng
AU - Vilas-Varela, Manuel
AU - Lawrence, James
AU - Mohammed, Mohammed S.G.
AU - Berdonces-Layunta, Alejandro
AU - Barragán, Ana
AU - Pascual, Jose Ignacio
AU - Lobo-Checa, Jorge
AU - Peña, Diego
AU - de Oteyza, Dimas G.
N1 - Funding Information:
The project leading to this publication has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No 635919), from the Spanish Ministry of Economy, Industry and Competitiveness (MINECO, Grant Nos. MAT2016-78293-C6-R) and María de Maeztu Units of Excellence Program MDM-2026-0618. We also acknowledge financial support from the Xunta de Galicia (Centro singular de investigación de Galicia, accreditation 2016–2019, ED431G/09) and Fondo Europeo de Desarrollo Regional (FEDER). This work used the “Imbabura” computer cluster of Yachay Tech University, which was purchased under contract No. 2017-024 (SIE-UITEY-007-2017). A.P.P. thanks D.J. Mowbray for his assistance with the computer cluster. We acknowledge the Paul Scherrer Institut, Villigen, Switzerland for provision of synchrotron radiation beamtime at PEARL beamline and would like to thank N. P. M. Bachellier and M. Muntwiller for assistance. We thank R. Fasel and R. Widmer for provision of substrate and sample holder for the synchrotron experiments.
Publisher Copyright:
© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
PY - 2019/9/17
Y1 - 2019/9/17
N2 - Within the collection of surface-supported reactions currently accessible for the production of extended molecular nanostructures under ultra-high vacuum, Ullmann coupling has been the most successful in the controlled formation of covalent single C−C bonds. Particularly advanced control of this synthetic tool has been obtained by means of hierarchical reactivity, commonly achieved by the use of different halogen atoms that consequently display distinct activation temperatures. Here we report on the site-selective reactivity of certain carbon-halogen bonds. We use precursor molecules halogenated with bromine atoms at two non-equivalent carbon atoms and found that the Ullmann coupling occurs on Au(111) with a remarkable predilection for one of the positions. Experimental evidence is provided by means of scanning tunneling microscopy and core level photoemission spectroscopy, and a rationalized understanding of the observed preference is obtained from density functional theory calculations.
AB - Within the collection of surface-supported reactions currently accessible for the production of extended molecular nanostructures under ultra-high vacuum, Ullmann coupling has been the most successful in the controlled formation of covalent single C−C bonds. Particularly advanced control of this synthetic tool has been obtained by means of hierarchical reactivity, commonly achieved by the use of different halogen atoms that consequently display distinct activation temperatures. Here we report on the site-selective reactivity of certain carbon-halogen bonds. We use precursor molecules halogenated with bromine atoms at two non-equivalent carbon atoms and found that the Ullmann coupling occurs on Au(111) with a remarkable predilection for one of the positions. Experimental evidence is provided by means of scanning tunneling microscopy and core level photoemission spectroscopy, and a rationalized understanding of the observed preference is obtained from density functional theory calculations.
KW - Ullmann coupling
KW - density functional calculations
KW - graphene nanoribbons
KW - hierarchical synthesis
KW - scanning probe microscopy
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U2 - 10.1002/cphc.201900633
DO - 10.1002/cphc.201900633
M3 - Article
C2 - 31328365
AN - SCOPUS:85071269210
VL - 20
SP - 2305
EP - 2310
JO - ChemPhysChem
JF - ChemPhysChem
SN - 1439-4235
IS - 18
ER -