In this work, we simulate the excited state proton transfer (ESPT) reaction involving the pyranine photoacid and an acetate molecule as proton acceptor, connected by a bridge water molecule. We employ ab initio molecular dynamics combined with an hybrid quantum/molecular mechanics (QM/MM) framework. Furthermore, a time-resolved vibrational analysis based on the wavelet-transform allows one to identify two low frequency vibrational modes that are fingerprints of the ESPT event: a ring wagging and ring breathing. Their composition suggests their key role in optimizing the structure of the proton donor-acceptor couple and promoting the ESPT event. We find that the choice of the QM/MM partition dramatically affects the photoinduced reactivity of the system. The QM subspace was gradually extended including the water molecules directly interacting with the pyranine-water-acetate system. Indeed, the ESPT reaction takes place when the hydrogen bond network around the reactive system is taken into account at full QM level.

Water-Mediated Excited State Proton Transfer of Pyranine-Acetate in Aqueous Solution: Vibrational Fingerprints from Ab Initio Molecular Dynamics / Chiariello, M. G.; Raucci, U.; Donati, G.; Rega, N.. - In: JOURNAL OF PHYSICAL CHEMISTRY. A, MOLECULES, SPECTROSCOPY, KINETICS, ENVIRONMENT, & GENERAL THEORY. - ISSN 1089-5639. - 125:17(2021), pp. 3569-3578. [10.1021/acs.jpca.1c00692]

Water-Mediated Excited State Proton Transfer of Pyranine-Acetate in Aqueous Solution: Vibrational Fingerprints from Ab Initio Molecular Dynamics

Chiariello M. G.;Raucci U.;Donati G.
Penultimo
;
Rega N.
2021

Abstract

In this work, we simulate the excited state proton transfer (ESPT) reaction involving the pyranine photoacid and an acetate molecule as proton acceptor, connected by a bridge water molecule. We employ ab initio molecular dynamics combined with an hybrid quantum/molecular mechanics (QM/MM) framework. Furthermore, a time-resolved vibrational analysis based on the wavelet-transform allows one to identify two low frequency vibrational modes that are fingerprints of the ESPT event: a ring wagging and ring breathing. Their composition suggests their key role in optimizing the structure of the proton donor-acceptor couple and promoting the ESPT event. We find that the choice of the QM/MM partition dramatically affects the photoinduced reactivity of the system. The QM subspace was gradually extended including the water molecules directly interacting with the pyranine-water-acetate system. Indeed, the ESPT reaction takes place when the hydrogen bond network around the reactive system is taken into account at full QM level.
2021
Water-Mediated Excited State Proton Transfer of Pyranine-Acetate in Aqueous Solution: Vibrational Fingerprints from Ab Initio Molecular Dynamics / Chiariello, M. G.; Raucci, U.; Donati, G.; Rega, N.. - In: JOURNAL OF PHYSICAL CHEMISTRY. A, MOLECULES, SPECTROSCOPY, KINETICS, ENVIRONMENT, & GENERAL THEORY. - ISSN 1089-5639. - 125:17(2021), pp. 3569-3578. [10.1021/acs.jpca.1c00692]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/886368
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