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  • Predicting Antioxidant Capacity: Theoretical Chemistry Matching Experiments

    Speaker: Professor Annia Galano
    Institute: Universidad Autónoma Metropolitana
    Country: Mexico
    Speaker Link:

    Annia Galano

    Departamento de Química. Universidad Autónoma Metropolitana-Iztapalapa.
    San Rafael Atlixco 186, Col. Vicentina. Iztapalapa. C. P. 09340. México D. F. México.

    Video Recording

    Video is available only for registered users.


    Oxidative stress is frequently caused by an excess of free radicals and has been associated with a wide variety of health disorders. Therefore, finding strategies for scavenging free radicals, or preventing their formation, has become an active area of research. Different reaction mechanisms involved in the chemical protection exerted by antioxidants will be discussed, as well as their relative importance depending on several aspects. A computational strategy designed to be a reliable tool in the study of radical-molecule reactions in solution is presented. It is referred to as Quantum Mechanics-based Test for Overall Free Radical Scavenging Activity (QM-ORSA). This methodology is intended to provide a universal and quantitative way of evaluating the free radical scavenging activity of chemical compounds. i.e. its primary antioxidant activity. This proposal includes a separated quantification of the activity in polar (aqueous) and non-polar (lipid) media. It also includes two different scales for quantification: absolute (based on overall apparent rate coefficients) and relative (using Trolox as the reference antioxidant). Using QM-ORSA also allows identifying the main mechanisms of reaction involved in the free radical scavenging activity of antioxidants, and establishing the influence of pH on such an activity. Validation of the QM-ORSA protocol by comparison with experimental results, is also presented, which demonstrate that its uncertainties are no larger than those arising from experiments.

  • Proton-Coupled Electron Transfer: Theoretical Perspectives and Applications

    Speaker: Professor Sharon Hammes-Schiffer
    Institute: SLAC National Accelerator Laboratory
    Country: USA
    Speaker Link:

    Sharon Hammes-Schiffer

    Stanford Institute for Materials and Energy Sciences,
    SLAC National Accelerator Laboratory, Menlo Park, CA-94025, USA

    Video Recording


    Proton-coupled electron transfer (PCET) reactions play a vital role in a wide range of chemical and biological processes. This talk will focus on the theory of PCET and applications to catalysis and energy conversion. The quantum mechanical effects of the active electrons and transferring proton, as well as the motions of the proton donor-acceptor mode and solvent or protein environment, are included in a general theoretical formulation. This formulation enables the calculation of rate constants and kinetic isotope effects for comparison to experiment. Recent extensions enable the study of heterogeneous as well as homogeneous interfacial PCET processes. Applications to PCET in molecular electrocatalysts for water splitting, CH bond activation, photoreduced zinc-oxide nanocrystals, and proton discharge on a gold electrode will be discussed. In addition, theoretical approaches for simulating the ultrafast dynamics of photoinduced PCET, along with applications to solvated molecular systems and photoreceptor proteins, will be discussed. Overall, these studies have identified the thermodynamically and kinetically favorable mechanisms, as well as the roles of proton relays, excited vibronic states, hydrogen tunneling, reorganization, and conformational motions. The resulting insights are guiding the design of more effective catalysts and energy conversion devices.



  • Quantum dynamics and its theoretical challenges

    Speaker: Professor Shirin Faraji
    Institute: Zernike Institute for Advanced Materials
    Country: The Netherlands
    Speaker Link:

    Shirin Faraji

    Faculty of Science and Engineering
    Theoretical Chemistry — Zernike Institute for Advanced Materials
    The Netherlands