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Excited-state symmetry breaking: from fundamental photophysics to asymmetrical photochemistry

Contributeurs/tricesDereka, Bogdan
Directeurs/tricesVauthey, Ericorcid
Date de soutenance2018-01-25
Résumé

Excited-state symmetry breaking in multipolar organic molecules is extensively investigated here. First unambiguous experimental observation of this phenomenon by using femtosecond time-resolved infrared spectroscopy (TRIR) is presented. This photophysical phenomenon originates from the fluctuations and rearrangement of solvent molecules around the electronically excited chromophore. Non-specific quadrupolar and dipolar, as well as specific H-bonding and non-orthodox X-bonding solute-solvent interactions can induce symmetry breaking, whereas dispersion and intramolecular distortions/asymmetric vibrations cannot. The effect of intramolecular factors, e.g. of the length of charge-transfer branches, is studied. Symmetry breaking leads to the asymmetrical reactivity of the seemingly identical molecular branches that can be utilized to achieve asymmetrical intra- and intermolecular photochemistry. Additionally, a novel approach to the time-resolved infrared spectroscopy ('solute-pump/solvent-probe') is demonstrated. It is used to decipher the mechanism of H-Bond Induced Nonradiative Deactivation (HBIND) of a quadrupolar molecular rod in highly protic alcohols.

eng
Mots-clés
  • Time-resolved infrared spectroscopy
  • TRIR
  • Symmetry breaking
  • Multipolar molecules
  • Excited-state dynamics
  • H-bonding
  • Asymmetrical photochemistry
  • Alkyne-allene reaction
  • Quadrupolar molecules
  • Octupolar molecules
  • Solvation.
Groupe de recherche
Citation (format ISO)
DEREKA, Bogdan. Excited-state symmetry breaking: from fundamental photophysics to asymmetrical photochemistry. 2018. doi: 10.13097/archive-ouverte/unige:102503
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Informations techniques

Création19.02.2018 12:22:00
Première validation19.02.2018 12:22:00
Heure de mise à jour15.03.2023 07:54:02
Changement de statut15.03.2023 07:54:01
Dernière indexation29.01.2024 21:23:24
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