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X-Ray induced redox-isomeric transformations of lanthanide bis-phthalocyaninates at the air-water interfaceстатья
Статья опубликована в высокорейтинговом журнале
Статья опубликована в журнале из списка Web of Science и/или Scopus- Авторы: Arakcheev A.V., Shcherbina M.A., Naumkin A.V., Raitman O.A., Raitman E.V., Repchenko Yu L., Grafov O.Yu, Martynov A.G., Gorbunova Yu G., Chvalun S.N., Selektor S.L.
- Журнал: SURFACES AND INTERFACES
- Том: 56
- Номер: 1
- Год издания: 2025
- Номер статьи: 105682
- DOI: 10.1016/j.surfin.2024.105682
- Аннотация: The redox-isomeric transitions in Langmuir monolayers of sandwich europium and samarium bis-phthalocyaninates have been studied using simultaneous in situ measurements by UV-visible reflection-absorption spectroscopy and XANES spectra. The inducing role of X-Ray irradiation in such transitions has been revealed for the first time. The studied switches are related to the intramolecular electron transfer between metal and ligand in the investigated complexes in 2D systems under the influence of external factors such as pressure and X-Ray irradiation ([Ln3+(R4Pc2-)(R4Pc•-)]0 [Ln2+(R4Pc•-)2]0). Such switches are particularly interesting due to the fact that they can change a number of physicochemical properties of the investigated ultrathin films, such as their optical properties, electrical conductivity, and magnetic behavior. It was found that, for both complexes, the UV-Vis spectra underwent reversible changes that are typical of redox-isomeric switching upon surface pressure changes in the monolayer, but no change in the position of the white line of the metal center absorption edge, which was expected for intramolecular electron transfer, was registered. Studies of Langmuir-Blodgett films (LBF) of europium and samarium bis-phthalocyaninates on solid substrates by X-Ray photoelectron spectroscopy confirmed the capability of both of the above-mentioned factors to cause tautomeric transitions in the 2D systems considered. In the spectra of the films transferred onto glass substrates at different surface pressures, differences in the electronic structure of the phthalocyanine ligands were registered. They were assigned to the change in the molecular orbital structure upon electron transfer from the ligand to the metal center (i.e., upon intramolecular oxidation of the ligand). At the same time, the cations of both metals also showed a rapid transition to the Ln3+ state under the influence of X-Ray irradiation. The connection of the mechanism of X-ray induced lanthanide complexes redox isomerization with photoionization upon reaching the metal center (Sm or Eu) absorption edge was demonstrated. Thus, in this work we have obtained direct evidence for the possibility of controlling the redox isomeric state of lanthanide bis-phthalocyaninates in 2D systems by changing the monolayer surface pressure, and also revealed one more governing factor for such molecular switches – X-Ray irradiation near the metal center absorption edge.
- Добавил в систему: Селектор София Львовна
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