Entropy–energy balance in base catalyzed keto-enol interconversion: A joint theoretical and experimental investigation

Authors

  • Massimiliano Aschi,

    Corresponding author
    1. Dipartimento di Chimica, Ingegneria Chimica e Materiali, Università degli Studi di L'Aquila, Via Vetoio, Coppito 67010, L'Aquila, Italia
    • Dipartimento di Scienze e Tecnologie Chimiche, Universita' di Roma “Tor Vergata” via della Ricerca Scientifica 1, Roma 00133, Italia
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  • Romina Zappacosta,

    1. Dipartimento di Scienze del Farmaco, Università “G. d'Annunzio”, Via dei Vestini, Chieti 66013, Italia
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  • Paolo DE Maria,

    1. Dipartimento di Scienze del Farmaco, Università “G. d'Annunzio”, Via dei Vestini, Chieti 66013, Italia
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  • Gabriella Siani,

    1. Dipartimento di Scienze del Farmaco, Università “G. d'Annunzio”, Via dei Vestini, Chieti 66013, Italia
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  • Antonella Fontana,

    1. Dipartimento di Scienze del Farmaco, Università “G. d'Annunzio”, Via dei Vestini, Chieti 66013, Italia
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  • Andrea Amadei

    Corresponding author
    1. Dipartimento di Scienze e Tecnologie Chimiche, Universita' di Roma “Tor Vergata” via della Ricerca Scientifica 1, Roma 00133, Italia
    • Dipartimento di Scienze e Tecnologie Chimiche, Universita' di Roma “Tor Vergata” via della Ricerca Scientifica 1, Roma 00133, Italia
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  • This article is dedicated to Prof S. Canuto on the occasion of his 60th birthday.

Abstract

The mechanism of base catalyzed keto-enol interconversion of aqueous 2-phenylacetylthiophene has been investigated by a joint application of experimental and computational approaches. Primarily we have focused our attention on the water-enolate proton transfer representing the rate determining step of the reaction. Computational results, in good agreement with experimental data demonstrate the crucial role exerted by the solvent. In particular, beyond the bulk catalytic effect an explicit assistance of solvent molecules allows the reaction to increase its efficiency. A combination on Molecular Dynamics simulations and Perturbed Matrix Method calculations also highlight the subtle balance between energetic and entropic effects which characterize the mechanistic scenario. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010

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