title: Competition between Hydrogen Bonds and Coordination Bonds Steered by the Surface Molecular Coverage.
abstract: In addition to the choices of metal atoms/molecular linkers and surfaces, several crucial parameters, including surface temperature, molecular stoichiometric ratio, electrical stimulation, concentration, and solvent effect for liquid/solid interfaces, have been demonstrated to play key roles in the formation of on-surface self-assembled supramolecular architectures. Moreover, self-assembled structural transformations frequently occur in response to a delicate control over those parameters, which, in most cases, involve either conversions from relatively weak interactions to stronger ones (e.g., hydrogen bonds to coordination bonds) or transformations between the comparable interactions (e.g., different coordination binding modes or hydrogen bonding configurations). However, intermolecular bond conversions from relatively strong coordination bonds to weak hydrogen bonds were rarely reported. Moreover, to our knowledge, a reversible conversion between hydrogen bonds and coordination bonds has not been demonstrated before. Herein, we have demonstrated a facile strategy for the regulation of stepwise intermolecular bond conversions from the metal-organic coordination bond (Cu-N) to the weak hydrogen bond (CH···N) by increasing the surface molecular coverage. From the DFT calculations we quantify that the loss in intermolecular interaction energy is compensated by the increased molecular adsorption energy at higher molecular coverage. Moreover, we achieved a reversible conversion from the weak hydrogen bond to the coordination bond by decreasing the surface molecular coverage.
authors.affiliation: Interdisciplinary Materials Research Center, Tongji-Aarhus Joint Research Center for Nanostructures and Functional Nanomaterials, College of Materials Science and Engineering, Tongji University , Shanghai 201804, P. R. China.
authors.forename: Liangliang
authors.initials: L
authors.lastname: Cai
authors.affiliation: Interdisciplinary Materials Research Center, Tongji-Aarhus Joint Research Center for Nanostructures and Functional Nanomaterials, College of Materials Science and Engineering, Tongji University , Shanghai 201804, P. R. China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Sun
authors.affiliation: Interdisciplinary Materials Research Center, Tongji-Aarhus Joint Research Center for Nanostructures and Functional Nanomaterials, College of Materials Science and Engineering, Tongji University , Shanghai 201804, P. R. China.
authors.forename: Meiling
authors.initials: M
authors.lastname: Bao
authors.affiliation: Interdisciplinary Materials Research Center, Tongji-Aarhus Joint Research Center for Nanostructures and Functional Nanomaterials, College of Materials Science and Engineering, Tongji University , Shanghai 201804, P. R. China.
authors.forename: Honghong
authors.initials: H
authors.lastname: Ma
authors.affiliation: Interdisciplinary Materials Research Center, Tongji-Aarhus Joint Research Center for Nanostructures and Functional Nanomaterials, College of Materials Science and Engineering, Tongji University , Shanghai 201804, P. R. China.
authors.forename: Chunxue
authors.initials: C
authors.lastname: Yuan
authors.affiliation: Interdisciplinary Materials Research Center, Tongji-Aarhus Joint Research Center for Nanostructures and Functional Nanomaterials, College of Materials Science and Engineering, Tongji University , Shanghai 201804, P. R. China.
authors.forename: Wei
authors.identifier: 0000-0003-0216-794X
authors.initials: W
authors.lastname: Xu
keywords: bond conversion; hydrogen bond; metal−organic coordination bond; scanning tunneling microscopy; self-assembly