title: Proton and Electron Transfer Mechanisms in the Formation of Neutral and Charged Quinhydrone-Like Complexes: A Multilayered Computational Study.
abstract: The redox and proton transfer processes involving the several dimers arising from quinones are studied by quantum mechanical methods using second order perturbation theory (MP2) and a medium size basis set optimized for reproducing dispersion interactions. Furthermore, bulk solvent effects are taken into account by the polarizable continuum solvent (PCM) approach possibly integrated by two explicit water molecules for an improved description of the cybotactic region. Our results indicate that several neutral and anionic dimers are kept together mainly by strong hydrogen bonds, but dispersion forces introduce additional non-negligible effects. The computed energy paths indicate that a proton transfer process should accompany the two-electron reduction of quinhydrone and that two dimers in the reduced form can be simultaneously present in solution, in agreement with available experimental data.
authors.affiliation: Scuola Normale Superiore , Piazza dei Cavalieri 7, I-56126 Pisa, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Barone
authors.affiliation: Dipartimento di Chimica e Chimica Industriale, Università di Pisa , Via Risorgimento 35, I-56126 Pisa, Italy.
authors.forename: Ivo
authors.initials: I
authors.lastname: Cacelli
authors.affiliation: Istituto di Chimica dei Composti OrganoMetallici (ICCOM-CNR) , Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Ferretti
authors.affiliation: Istituto di Chimica dei Composti OrganoMetallici (ICCOM-CNR) , Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa, Italy.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Prampolini
authors.affiliation: Istituto di Chimica dei Composti OrganoMetallici (ICCOM-CNR) , Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Villani