Electronic excitations in epicocconone analogues: TDDFT methodological assessment guided by experiment

J Phys Chem A. 2012 Aug 23;116(33):8634-43. doi: 10.1021/jp305269y. Epub 2012 Aug 10.

Abstract

In this work we present a combined theoretical and experimental study of UV/vis absorption spectra of novel organic chromophores derived from epicocconone. A computational protocol, consistent with experimental findings, is proposed in the framework of time-dependent density functional theory. More precisely, the influence of density functional, basis set, and solvation effects is assessed through theory-experiment matching. On the one hand, it is shown that global hybrid functionals fail to describe excitation spectra for the whole training set. On the other hand, range-separated hybrids allow a description of the complete set of epicocconone derivatives on equal footing, while the double-ζ basis set is shown to be sufficiently accurate for the screening of the spectroscopic properties in epicocconone analogues. The inclusion of solvent effects within a polarizable continuum model appears to be compulsory to decrease the residual dispersion. State specific solvation, on the contrary, does not provide a significant consistency/accuracy improvement. Besides, conformational transformations in investigated compounds and their influence on electronic absorption spectra are pointed out. A systematic choice of the same conformation for each compound from the training set enhances consistency and accuracy of our theoretical model. Lastly, a TDDFT-based calibration is proposed for prediction of absorption wavelengths in epicocconone analogues.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Benzopyrans / chemistry*
  • Electrons*
  • Furans / chemistry*
  • Ketones / chemistry*
  • Quantum Theory*
  • Spectrophotometry, Ultraviolet
  • Time Factors

Substances

  • Benzopyrans
  • Furans
  • Ketones
  • epicocconone