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Adsorption of Expanded Pyridinium Molecules at the Electrified Interface and Its Effect on the Electron-Transfer Process
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SYSNO ASEP 0490605 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Adsorption of Expanded Pyridinium Molecules at the Electrified Interface and Its Effect on the Electron-Transfer Process Author(s) Nováková Lachmanová, Štěpánka (UFCH-W) ORCID, RID
Dupeyre, G. (FR)
Lainé, P. P. (FR)
Hromadová, Magdaléna (UFCH-W) RID, ORCID, SAISource Title Langmuir. - : American Chemical Society - ISSN 0743-7463
Roč. 34, č. 22 (2018), s. 6405-6412Number of pages 8 s. Language eng - English Country US - United States Keywords adsorption ; cyclic voltammetry ; electron transition Subject RIV CG - Electrochemistry OECD category Electrochemistry (dry cells, batteries, fuel cells, corrosion metals, electrolysis) R&D Projects GA16-03085S GA ČR - Czech Science Foundation (CSF) GJ16-07460Y GA ČR - Czech Science Foundation (CSF) GA18-04682S GA ČR - Czech Science Foundation (CSF) Institutional support UFCH-W - RVO:61388955 UT WOS 000434893600010 EID SCOPUS 85047071190 DOI 10.1021/acs.langmuir.8b00671 Annotation Adsorption properties of a series of redox-active expanded pyridinium molecules were studied at an electrified interface by cyclic and alternating current voltammetry methods. It was shown that the adsorbed state can sufficiently block N-pyramidalization of the pyridinium redox center of 2′,6′-diphenyl-[4,1′:4′,4′′-terpyridin]-1′-ium tetrafluoroborate (2), leading to a change of the mechanism from a single two-electron-transfer process to stepwise transfer of two electrons. Chemically locked molecules 1, 9-(pyridin-4-yl)benzo[c]benzo[1,2]quinolizino[3,4,5,6-ija][1,6]naphthyridin-15-ium tetrafluoroborate (ring fusion), and 3, 3,5-dimethyl-2′,6′-diphenyl-[4,1′:4′,4′′-terpyridin]-1′-ium tetrafluoroborate (steric hindrance) do not enable N-pyramidalization of the redox center upon electron transfer (ET) and serve as references. It was shown that 1 follows Langmuir-type adsorption around a potential of zero charge and that 1-3 form a close-packed film with some repulsive interactions between individual molecules at potentials where ET takes place. It has been suggested that all three molecules lie flat on the electrode surface, with the lowest free energy of adsorption found for 2. Maximum surface concentration Γ∗ equal to (1.4 ± 0.1) × 10-10mol·cm-2was found for 1, (1.5 ± 0.1) × 10-10mol·cm-2for 2, and (1.6 ± 0.1) × 10-10mol·cm-2for 3. These findings will help to clarify the role of molecular contacts with conducting substrate in the single-molecule electron-transport measurements of 1-3 during the metal-molecule-metal junction formation process. Workplace J. Heyrovsky Institute of Physical Chemistry Contact Michaela Knapová, michaela.knapova@jh-inst.cas.cz, Tel.: 266 053 196 Year of Publishing 2019
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