Examinando por Autor "Wrighton-Araneda, Kerry"

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    Ítem
    Non-covalent interactions in hexanuclear polyoxidometalates [VIV6B20O50H8]8−. An experimental and theoretical approach
    (Elsevier Ltd, 2022-01-01) Muñoz-Becerra, Karina; Wrighton-Araneda, Kerry; Le Fur, Eric; Saillard, Jean-Yves; Kahlal, Samia; Cador, Olivier; Paredes-García, Verónica; Venegas-Yazigi, Diego
    A complete study of the optical and magnetic properties of three new {V6-type} polyoxidometalates (NH3CH2CH2CH2NH3)4{V6B20O50H8}·4H2O 1, K2(NH3CH2CH2NH3)2.5(NH3CH2CH2NH2){V6B20O50H8}·2H2O 2, and K2(NH3CH2CH2CH2NH3)2(H3O)2{V6B20O50H8}·8H2O 3 is presented. Using TD-DFT calculations, the assignment of the experimental UV–Visible spectra was established with four absorption bands: a higher in energy assigned to metal-to-metal charge transfer and the remaining associated principally to d-d transitions, demonstrating that the {V6IVO18}12− ring is the principal chromophore for these systems and that the surrounding packing does not have an influence on it. On the other hand, the differences observed in the magnetic properties are caused by the influence of the non-covalent interactions between the potassium ions with some oxygen atoms of the VIV coordination spheres, thus modifying the VIV-VIV exchange coupling. This effect was demonstrated using a simplified binuclear DFT model that predicts a higher VIV-VIV antiferromagnetic coupling when the K cations become closer to the oxygen bridge atoms that link the VIV centres of the {V6IVO18}12− ring. © 2021
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    Ítem
    Substitution effect on the charge transfer processes in organo-imido lindqvist-polyoxomolybdate
    (MDPI, 2018-12) Hermosilla-Ibáñez, Patricio; Wrighton-Araneda, Kerry; Cañón-Mancisidor, Walter; Gutiérrez-Cutiño, Marlen; Paredes-García, Verónica; Venegas-Yazigi, Diego
    Two new aromatic organo-imido polyoxometalates with an electron donor triazole group ([n-Bu4N]2[Mo6O18NC6H4N3C2H2]) (1) and a highly conjugated fluorene ([n-Bu4N]2[Mo6O18NC13H9]) (2) have been obtained. The electrochemical and spectroscopic properties of several organo-imido systems were studied. These properties were analysed by the theoretical study of the redox potentials and by means of the excitation analysis, in order to understand the effect on the substitution of the organo-imido fragment and the effect of the interaction to a metal centre. Our results show a bathochromic shift related to the charge transfer processes induced by the increase of the conjugated character of the organic fragment. The cathodic shift obtained from the electrochemical studies reflects that the electronic communication and conjugation between the organic and inorganic fragments is the main reason of this phenomenon. © 2018 by the authors. Licensee MDPI, Basel, Switzerland.