title: Supramolecular architectures on surfaces formed through hydrogen bonding optimized in three dimensions.
abstract: 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.
authors.affiliation: Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and Astronomy Aarhus University, 8000 Aarhus, Denmark.
authors.forename: Miao
authors.initials: M
authors.lastname: Yu
authors.forename: Nataliya
authors.initials: N
authors.lastname: Kalashnyk
authors.forename: Wei
authors.initials: W
authors.lastname: Xu
authors.forename: Régis
authors.initials: R
authors.lastname: Barattin
authors.forename: Youness
authors.initials: Y
authors.lastname: Benjalal
authors.forename: Erik
authors.initials: E
authors.lastname: Laegsgaard
authors.forename: Ivan
authors.initials: I
authors.lastname: Stensgaard
authors.forename: Mohamed
authors.initials: M
authors.lastname: Hliwa
authors.forename: Xavier
authors.initials: X
authors.lastname: Bouju
authors.forename: André
authors.initials: A
authors.lastname: Gourdon
authors.forename: Christian
authors.initials: C
authors.lastname: Joachim
authors.forename: Flemming
authors.initials: F
authors.lastname: Besenbacher
authors.forename: Trolle R
authors.initials: TR
authors.lastname: Linderoth