Observations of carbon-carbon coupling of 4,4-dibromo-p-terphenyl on Cu(110) surface at molecular level

The carbon-carbon couplings of 4,4-dibromo-p-terphenyl (DBTP) on Cu(110) surface have been investigated at a single molecular level by scanning tunneling microscopy. After annealing at 353 K, a mixture of parallel non-organometallic and organometallic intermediates of DBTP molecules along the [1-10] direction of the surface has been observed. Further annealing at 393 K causes one group of molecules to form oligomers with para-para and para-meta motifs via Ullmann reaction and the other group of molecules to synthesize oligomers with meta-meta motifs via direct carbon-carbon coupling reaction. Statistical results directly reveal that the occurrence of reaction type is strongly related to the initial binding configuration of DBTP molecules. (C) 2016 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.