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

ContributorsDereka, Bogdan
DirectorsVauthey, Ericorcid
Defense date2018-01-25
Abstract

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.

Keywords
  • Time-resolved infrared spectroscopy
  • TRIR
  • Symmetry breaking
  • Multipolar molecules
  • Excited-state dynamics
  • H-bonding
  • Asymmetrical photochemistry
  • Alkyne-allene reaction
  • Quadrupolar molecules
  • Octupolar molecules
  • Solvation
Research groups
Citation (ISO format)
DEREKA, Bogdan. Excited-state symmetry breaking: from fundamental photophysics to asymmetrical photochemistry. Doctoral Thesis, 2018. doi: 10.13097/archive-ouverte/unige:102503
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Creation19/02/2018 12:22:00
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