Supramolecular architectures on surfaces formed through hydrogen bonding optimized in three dimensions.
Supramolecular self-assembly on surfaces, guided by hydrogen bonding interactions, has been widely studied, most often involving planar compounds confined directly onto surfaces in a planar two-dimensional (2-D) geometry and equipped with structurally rigid chemical functionalities to direct the self-assembly. In contrast, so-called molecular Landers are a class of compounds that exhibit a pronounced three-dimensional (3-D) structure once adsorbed on surfaces, arising from a molecular backboard equipped with bulky groups which act as spacer legs. Here we demonstrate the first examples of extended, hydrogen-bonded surface architectures formed from molecular Landers. Using high-resolution scanning tunnelling microscopy (STM) under well controlled ultrahigh vacuum conditions we characterize both one-dimensional (1-D) chains as well as five distinct long-range ordered 2-D supramolecular networks formed on a Au(111) surface from a specially designed Lander molecule equipped with dual diamino-triazine (DAT) functional moieties, enabling complementary NH...N hydrogen bonding. Most interestingly, comparison of experimental results to STM image calculations and molecular mechanics structural modeling demonstrates that the observed molecular Lander-DAT structures can be rationalized through characteristic intermolecular hydrogen bonding coupling motifs which would not have been possible in purely planar 2-D surface assembly because they involve pronounced 3-D optimization of the bonding configurations. The described 1-D and 2-D patterns of Lander-DAT molecules may potentially be used as extended molecular molds for the nucleation and growth of complex metallic nanostructures.
Yu
Miao
M
Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and Astronomy Aarhus University, 8000 Aarhus, Denmark.
Kalashnyk
Nataliya
N
Xu
Wei
W
Barattin
Régis
R
Benjalal
Youness
Y
Laegsgaard
Erik
E
Stensgaard
Ivan
I
Hliwa
Mohamed
M
Bouju
Xavier
X
Gourdon
André
A
Joachim
Christian
C
Besenbacher
Flemming
F
Linderoth
Trolle R
TR