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Exciton coupling between enones: Quassinoids revisited.

Gennaro PescitelliDaniele Barbaro
Published in: Chirality (2017)
The electronic circular dichroism (ECD) spectra of two previously reported quassinoids containing a pair of enone chromophores are revisited to gain insight into the consistency and applicability of the exciton chirality method. Our study is based on time-dependent Density Functional Theory calculations, transition and orbital analysis, and numerical exciton coupling calculations. In quassin (1) the enone/enone exciton coupling is quasi-degenerate, yielding strong rotational strengths that account for the observed ECD spectrum in the enone π-π* region. In perforalactone C (2) the nondegenerate coupling produces weak rotational strengths, and the ECD spectrum is dominated by other mechanisms of optical activity. We remark the necessity of a careful application of the nondegenerate exciton coupling method in similar cases.
Keyphrases
  • density functional theory
  • room temperature
  • molecular dynamics
  • energy transfer
  • mass spectrometry
  • quantum dots
  • solid state