Ultrafast ring-closure reaction of photochromic indolylfulgimides studied with UV-pump-IR-probe spectroscopy

J Phys Chem A. 2008 Jan 17;112(2):210-4. doi: 10.1021/jp073545p. Epub 2007 Dec 21.

Abstract

The ring-opening and ring-closure reactions of a photochromic indolylfulgimide are investigated with femtosecond vibrational spectroscopy. Spectral signatures due to excited-state decay and vibrational cooling are seen in the mid-IR region. For the ring-opening reaction triggered with visible pulses, a lifetime of the excited electronic state of 4 ps was obtained in polar solution. In a nonpolar solvent, this time constant is reduced to 2 ps. The ring-closure reaction induced with UV pulses displays an excited-state lifetime and thus a building of the photoproduct of roughly 0.5 ps. For all processes, the subsequent cooling occurs on a 15-ps time scale lasting up to approximately 50 ps. The time-resolved IR measurements do not support the existence of any long-living intermediate states.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Imides / chemistry*
  • Indoles / chemistry*
  • Isomerism
  • Molecular Structure
  • Photochemistry
  • Solvents
  • Spectrophotometry
  • Time Factors

Substances

  • Imides
  • Indoles
  • Solvents