Filters

2020 - 20243

More filters

2021 - 20243
Reset filters

Settings

Author: Popov, Alexey A. × Publisher: Weinheim : Wiley-VCH × Subject: spectroelectrochemistry ×

Search Results

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    On the Electrochemical Reduction of 4-(Thiazol-2-ylazo)-Substituted 1-Chloronaphthalenes: Formation and Characterization of Stable Radical Anions
    (Weinheim : Wiley-VCH, 2020) Dmitrieva, Evgenia; Popov, Alexey A.; Yu, Xiuling; Hartmann, Horst
    The electrochemical reduction of two chloro-substituted 4-(thiazol-2-ylazo)has been studied by means of spectroelectrochemistry and simulated with the DFT method. Whereas the 1-chloro-4-(4-chlorothiazol-2-ylazo)forms both a stable radical anion and a dianion, the dianion of 1-chloro-4-(thiazol-2-ylazo)is instable. In the radical anion of both compounds, the spin densities are high not only at the azo moiety but also at C3 in the naphthalene and at C5 in the thiazole moiety. This is in agreement with former experimental results demonstrating the remarkable reactivity of these positions towards thiols which can act as nucleophiles as well as electron donors. © 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
  • Thumbnail Image
    Item
    Between Aromatic and Quinoid Structure: A Symmetrical UV to Vis/NIR Benzothiadiazole Redox Switch
    (Weinheim : Wiley-VCH, 2020) Rietsch, Philipp; Sobottka, Sebastian; Hoffmann, Katrin; Popov, Alexey A.; Hildebrandt, Pascal; Sarkar, Biprajit; Resch-Genger, Ute; Eigler, Siegfried
    Reversibly switching the light absorption of organic molecules by redox processes is of interest for applications in sensors, light harvesting, smart materials, and medical diagnostics. This work presents a symmetrical benzothiadiazole (BTD) derivative with a high fluorescence quantum yield in solution and in the crystalline state and shows by spectroelectrochemical analysis that reversible switching of UV absorption in the neutral state, to broadband Vis/NIR absorption in the 1st oxidized state, to sharp band Vis absorption in the 2nd oxidized state, is possible. For the one-electron oxidized species, formation of a delocalized radical is confirmed by electron paramagnetic resonance spectroelectrochemistry. Furthermore, our results reveal an increasing quinoidal distortion upon the 1st and 2nd oxidation, which can be used as the leitmotif for the development of BTD based redox switches. © 2020 The Authors. Published by Wiley-VCH GmbH
  • Thumbnail Image
    Item
    On the Preparation and Spectroelectrochemical Characterization of Certain 2,5-Bis(het)aryl Substituted Thiophenes
    (Weinheim : Wiley-VCH, 2024) Dmitrieva, Evgenia; Barche, Jens; Popov, Alexey A.; Hartmann, Horst
    In this work, a series of novel 2,5-bis(het)aryl and 2,5-bis-thienyl substituted thiophenes have been synthesized and characterized by ultraviolet-visible-near infrared (UV-Vis-NIR) absorption and fluorescence spectroscopy as well as cyclic voltammetry. From the electron paramagnetic resonance (EPR)/UV-Vis-NIR spectroelectrochemical data, information about the optical and magnetic properties of the charged species of these compounds have been provided. The spin distributions in the electrochemically generated radical ions were estimated experimentally and compared with theoretical data.