3 research outputs found
Direct Evidence of Interfacial Hydrogen Bonding in Proton-Electron Concerted 2D Organic Bilayer on Au Substrate
No full textStrong Hydrogen Bonds at the Interface between Proton-Donating and -Accepting Self-Assembled Monolayers on Au(111)
No full textHydrogen-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
(H<sub>2</sub>Cat-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 H<sub>2</sub>Cat-BMT-TTF adlayer formations.
In the measurements by AFM, a grained H<sub>2</sub>Cat-BMT-TTF adlayer
on Im-SAM is revealed. The coverage and the chemical states of H<sub>2</sub>Cat-BMT-TTF on Im-SAM are specified by XPS. On the vibrational
spectrum measured by IRAS, the strong hydrogen bonds between H<sub>2</sub>Cat-BMT-TTF and Im-SAM are characterized by the remarkably
red-shifted OH stretching mode at 3140 cm<sup>–1</sup>, which
is much lower than that for hydrogen-bonding water (typically ∼3300
cm<sup>–1</sup>). The OH stretching mode frequency and the
adsorption strength for the H<sub>2</sub>Cat-BMT-TTF molecule hydrogen
bonding with imidazole groups are quantitatively examined on the basis
of DFT calculations
