Strong Hydrogen Bonds at the Interface between Proton-Donating and -Accepting Self-Assembled Monolayers on Au(111)

Hiroyuki S Kato; Shinya Yoshimoto; Akira Ueda; Susumu Yamamoto; Yusuke Kanematsu; Masanori Tachikawa; Hatsumi Mori; Jun Yoshinobu; Iwao Matsuda

doi:10.1021/acs.langmuir.7b03451

Strong Hydrogen Bonds at the Interface between Proton-Donating and -Accepting Self-Assembled Monolayers on Au(111)

Langmuir. 2018 Feb 6;34(5):2189-2197. doi: 10.1021/acs.langmuir.7b03451. Epub 2018 Jan 23.

Authors

Hiroyuki S Kato^{1

2}, Shinya Yoshimoto², Akira Ueda², Susumu Yamamoto², Yusuke Kanematsu³, Masanori Tachikawa⁴, Hatsumi Mori², Jun Yoshinobu², Iwao Matsuda²

Affiliations

¹ Department of Chemistry, Graduate School of Science, Osaka University , Toyonaka, Osaka 560-0043, Japan.
² The Institute for Solid State Physics (ISSP), The University of Tokyo , Kashiwa, Chiba 277-8581, Japan.
³ Faculty of Information Sciences, Hiroshima City University , 3-4-1, Hiroshima, Hiroshima 731-3194, Japan.
⁴ Graduate School of Nanobioscience, Yokohama City University , Yokohama, Kanagawa 236-0027, Japan.

PMID: 29359939
DOI: 10.1021/acs.langmuir.7b03451

Abstract

Hydrogen-bonding heterogeneous bilayers on substrates have been studied as a base for new functions of molecular adlayers by means of atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), infrared reflection absorption spectroscopy (IRAS), and density functional theory (DFT) calculations. Here, we report the formation of the catechol-fused bis(methylthio)tetrathiafulvalene (H₂Cat-BMT-TTF) adlayer hydrogen bonding with an imidazole-terminated alkanethiolate self-assembled monolayer (Im-SAM) on Au(111). The heterogeneous bilayer is realized by sequential two-step immersions in solutions for the individual Im-SAM and H₂Cat-BMT-TTF adlayer formations. In the measurements by AFM, a grained H₂Cat-BMT-TTF adlayer on Im-SAM is revealed. The coverage and the chemical states of H₂Cat-BMT-TTF on Im-SAM are specified by XPS. On the vibrational spectrum measured by IRAS, the strong hydrogen bonds between H₂Cat-BMT-TTF and Im-SAM are characterized by the remarkably red-shifted OH stretching mode at 3140 cm^-1, which is much lower than that for hydrogen-bonding water (typically ∼3300 cm^-1). The OH stretching mode frequency and the adsorption strength for the H₂Cat-BMT-TTF molecule hydrogen bonding with imidazole groups are quantitatively examined on the basis of DFT calculations.

Publication types

Research Support, Non-U.S. Gov't