Photochemistry of (η6-anisole)Cr(CO)3 and (η6-thioanisole)Cr(CO)3: evidence for a photoinduced haptotropic shift of the thioanisole ligand, a picosecond time-resolved infrared spectroscopy and density functional theory investigation

J Phys Chem A. 2012 Jan 26;116(3):962-9. doi: 10.1021/jp211726j. Epub 2012 Jan 12.

Abstract

The photochemistry of (η(6)-anisole)Cr(CO)(3) and (η(6)-thioanisole)Cr(CO)(3) was investigated by picosecond time-resolved infrared spectroscopy in n-heptane solution at 298 K. Two independent excited states are populated following 400 nm excitation of each of these complexes. An excited state with some metal-to-CO charge-transfer character is responsible for the CO-loss process, which is slow compared to CO-loss from Cr(CO)(6). Observed first order rate constants of 1.8 × 10(10) s(-1) and 2.5 × 10(10) s(-1) were obtained for the anisole and thioanisole complexes, respectively. The second excited state has metal-to-arene charge transfer character and results in a haptotropic shift of the thioanisole ligand. DFT calculations characterized the excited states involved and the nature of the haptotropic shift intermediate observed for the thioanisole species.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromium / chemistry*
  • Hydrocarbons, Chlorinated / chemistry*
  • Ligands
  • Photochemical Processes
  • Photochemistry
  • Quantum Theory*
  • Spectrophotometry, Infrared
  • Sulfides / chemistry*
  • Time Factors

Substances

  • Hydrocarbons, Chlorinated
  • Ligands
  • Sulfides
  • Chromium
  • methylphenylsulfide