title: Investigation on the Surface-Confined Self-Assembly Stabilized by Hydrogen Bonds of Urea and Amide Groups: Quantitative Analysis of Concentration Dependence of Surface Coverage.
abstract: Formation of a hydrogen-bond network via an amide group is a key driving force for the nucleation-elongation-type self-assembly that is often seen in biomolecules and artificial supramolecular assemblies. In this work, rod-coil-like aromatic compounds bearing an amide (1 a-3 a) or urea group (1 u-3 u) were synthesized, and their self-assemblies on a 2-D surface were investigated by scanning tunneling microscopy (STM). According to the quantitative analysis of the concentration dependence of the surface coverage, it was revealed that the strength of the hydrogen bond (i.e., amide or urea) and the number of non-hydrogen atoms in a molecular component (i.e., size of core and length of alkyl side chain) play a primary role in determining the stabilization energy during nucleation and elongation processes of molecular ordering on the HOPG surface.
authors.affiliation: Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto, 615-8510, Japan.
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Nishitani
authors.affiliation: Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto, 615-8510, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Hirose
authors.affiliation: Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto, 615-8510, Japan. kmatsuda@sbchem.kyoto-u.ac.jp.
authors.forename: Kenji
authors.initials: K
authors.lastname: Matsuda
mesh_terms: D000577:Amides / Q000737:chemistry*; D002210:Caprylates / Q000737:chemistry; D006108:Graphite / Q000737:chemistry; D006841:Hydrocarbons, Aromatic / Q000737:chemistry*; D006860:Hydrogen Bonding; D016252:Microscopy, Scanning Tunneling; D008958:Models, Molecular; D049329:Nanostructures / Q000737:chemistry; D013499:Surface Properties; D013816:Thermodynamics; D014508:Urea / Q000737:chemistry*
chemical_list: D000577:Amides; D002210:Caprylates; D006841:Hydrocarbons, Aromatic; D006108:Graphite; D014508:Urea; C031492:octanoic acid
keywords: hydrogen bond; scanning tunneling microscopy; self-assembled monolayer; thermodynamic model; urea