A theoretical study of the UV/visible absorption and emission solvatochromic properties of solvent-sensitive dyes

Chemphyschem. 2003 Oct 17;4(10):1084-94. doi: 10.1002/cphc.200300801.

Abstract

Using the density-functional vertical self-consistent reaction field (VSCRF) solvation model, incorporated with the conductor-like screening model (COSMO) and the self-consistent reaction field (SCRF) methods, we have studied the solvatochromic shifts of both the absorption and emission bands of four solvent-sensitive dyes in different solutions. The dye molecules studied here are: S-TBA merocyanine, Abdel-Halim's merocyanine, the rigidified amino-coumarin C153, and Nile red. These dyes were selected because they exemplify different structural features likely to impact the solvent-sensitive fluorescence of "push-pull", or merocyanine, fluorophores. All trends of the blue or red shifts were correctly predicted, comparing with the experimental observations. Explict H-bonding interactions were also considered in several protic solutions like H2O, methanol and ethanol, showing that including explicit H-bonding solvent molecule(s) in the calculations is important to obtain the correct order of the excitation and emission energies. The geometries, electronic structures, dipole moments, and intra- and intermolecular charge transfers of the dyes in different solvents are also discussed.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Absorption
  • Fluorescent Dyes / chemistry*
  • Hydrogen Bonding
  • Models, Chemical*
  • Molecular Structure
  • Solvents / chemistry
  • Spectrophotometry, Ultraviolet
  • Ultraviolet Rays*

Substances

  • Fluorescent Dyes
  • Solvents