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.