Characterization of Langmuir Monolayers of the Amphiphilic Ru Complex at the Air/Water Interface by Ultraviolet Photoelectron Yield Spectroscopy

Abstract

Ultraviolet photoelectron yield spectroscopy (UPYS) was applied to the characterization of Langmuir layers of the amphiphilic Ru complex at the air/water interface in ambient conditions. The UPY spectra were successfully obtained for Langmuir layers of the complex in the surface concentration range of 0.14−2.1 molecule nm-2, and the photoelectron emission threshold energy, E t, and photoelectron emission efficiency, α, were determined for the respective surface concentrations. The E t value was constant at lower surface concentration and decreased as the surface concentration of the complex was increased. The decrease in the E t value is considered to be due to the decrease in the distance between the Ru complexes in the two-dimensional gas phase and the following aggregation or crystallization considering the polarization effect on the photoionization hole state. The dependence of the α value upon the surface concentration of the complex also indicates the change in structure of the Langmuir layer of the Ru complex on the water surface. It is concluded that UPYS is applicable to the in situ characterization of Langmuir layers of photosensitive molecules at the air/water interface.

Surface and Aggregation Behavior of Aqueous Solutions of Ru(II) Metallosurfactants. 3. Effect of Chain Number and Orientation on the Structure of Adsorbed Films of [Ru(bipy)2(bipy‘)]Cl2 Complexes

“…Adsorption and organization of metallosurfactants at interfaces is central to the development of a range of hybrid materials, thin-film devices, and heterogeneous catalysts. , Accordingly, the interest in these materials has initiated a number of structural studies of the micelles and thin-film structures formed by metallosurfactants − as the numerous potential applications depend intimately on the relationship between molecular structure and packing ability. Since metallosurfactants offer a great deal of flexibility in their molecular design, this relationship between structure and function can, in principle, be tailored.…”

Ultrathin Luminescent Films of Rigid Dinuclear Ruthenium(II) Trisbipyridine Complexes

“…Among the transition-metal complexes studied in LB films, ruthenium(II) bipyridyl complexes have received considerable attention, [30][31][32][33][34] owing to their rich photo-and electrochemical behavior, [35,36] diversity of coordination forms, [37] high thermal and chemical stability, and high solubility in common solvents. LB films of different ruthenium complexes have already successfully been applied in high-performance sensors [38][39][40][41] and been shown to exhibit second harmonic generation activities.…”

Characterization of Catechins in Water by Photoemission Yield Spectroscopy in Air

“…Monjushiro et al reported that no photoemission was observed from pure water. 13 The photoemission spectrum of the pure water surface, which is shown in Fig. 3, exhibits the same trend.…”

“…It has been reported that PYSA is applicable to the in situ characterization of Langmuir layers of photosensitive molecules at the air/water interface in ambient conditions. 13 In this study, we applied PYSA to photoemission experiments on liquids, focusing on components in beverages, under the same conditions as our living environment.…”