10.1021/jacs.8b01658.s001 Qitang Fan Qitang Fan Simon Werner Simon Werner Jalmar Tschakert Jalmar Tschakert Daniel Ebeling Daniel Ebeling André Schirmeisen André Schirmeisen Gerhard Hilt Gerhard Hilt Wolfgang Hieringer Wolfgang Hieringer J. Michael Gottfried J. Michael Gottfried Precise Monoselective Aromatic C–H Bond Activation by Chemisorption of <i>Meta</i>-Aryne on a Metal Surface American Chemical Society 2018 Aromatic dissociation copper surface prototype molecules bond theory calculations meta dibromo phenyl ring scanning tunneling microscopy 1.12 eV chemical structures activation barrier terphenyl aryne species Cu force microscopy aryl-containing chemicals 2018-05-11 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Precise_Monoselective_Aromatic_C_H_Bond_Activation_by_Chemisorption_of_i_Meta_i_-Aryne_on_a_Metal_Surface/6447620 Aromatic C–H bond activation has attracted much attention due to its versatile applications in the synthesis of aryl-containing chemicals. The major challenge lies in the minimization of the activation barrier and maximization of the regioselectivity. Here, we report the highly selective activation of the central aromatic C–H bond in <i>meta</i>-aryne species anchored to a copper surface, which catalyzes the C–H bond dissociation. Two prototype molecules, i.e., 4′,6′-dibromo-<i>meta</i>-terphenyl and 3′,5′-dibromo-<i>ortho</i>-terphenyl, have been employed to perform C–C coupling reactions on Cu(111). The chemical structures of the resulting products have been clarified by a combination of scanning tunneling microscopy and noncontact atomic force microscopy. Both methods demonstrate a remarkable weakening of the targeted C–H bond. Density functional theory calculations reveal that this efficient C–H activation stems from the extraordinary chemisorption of the <i>meta</i>-aryne on the Cu(111) surface, resulting in the close proximity of the targeted C–H group to the Cu(111) surface and the absence of planarity of the phenyl ring. These effects lead to a lowering of the C–H dissociation barrier from 1.80 to 1.12 eV, in agreement with the experimental data.