Browsing by Author "Moens, Jan"

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    Can electrophilicity act as a measure of the redox potential of first-row transition metal ions?
    (WILEY-V C H VERLAG GMBH, 2007) Moens, Jan; Roos, Goedele; Jaque, Pablo; De Proft, Frank; Geerlings, Paul
    Previous contributions concerning the computational approach to redox chemistry have made use of thermodynamic cycles and Car-Parrinello molecular dynamics simulations to obtain accurate redox potential values, whereas this article adopts a conceptual density functional theory (DFT) approach. Conceptual DFT descriptors have found widespread use in the study of thermodynamic and kinetic aspects of a variety of organic and inorganic reactions. However, redox reactions have not received much attention until now. In this contribution, we prove the usefulness of global and local electrophilicity descriptors for the prediction of the redox characteristics of first row transition metal ions (from Sc3+vertical bar Sc2+ to Cu3+vertical bar Cu2+) and introduce a scaled definition of the electrophilicity based on the number of electrons an electrophile ideally accepts. This scaled electrophilicity concept acts as a good quantitative estimate of the redox potential. We also identify the first solvation sphere together with the metal ion as the primary active region during the electron uptake process, whereas the second solvation sphere functions as a non-reactive continuum region.
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    The study of redox reactions on the basis of conceptual DFT principles: EEM and vertical quantities
    (AMER CHEMICAL SOC, 2008) Moens, Jan; Jaque, Pablo; De Proft, Frank; Geerlings, Paul
    In this article, two new approaches are introduced which describe redox reactions through descriptors defined within the field of conceptual density functional theory (DFT). One approach starts with the grand canonical ensemble DFT from which a formula is derived for the chemical potential of the electrode in terms of intrinsic properties of oxidized and reduced states of the electroactive species. Second, starting from a Born-Haber scheme, the redox potential is solely expressed in terms of the vertical electron affinity and ionization potential of oxidized and reduced species, respectively. A large collection of 44 organic and inorganic systems are studied in different solvents including implicit and explicit solvation models. Both strategies seem well capable of reproducing experimental values of redox potentials.