Affordable Access

Publisher Website

Electron-transfer pathway for photoinduced Diels–Alder cycloadditions

Authors
Journal
Journal of Photochemistry and Photobiology A Chemistry
1010-6030
Publisher
Elsevier
Publication Date
Volume
122
Issue
2
Identifiers
DOI: 10.1016/s1010-6030(99)00007-6
Keywords
  • Photoinduced Diels-Alder
  • Electron-Transfer Quenching
  • Solvent-Dependent Quantum Yields
  • Fluorescence
  • Picosecond Absorption Spectroscopy
Disciplines
  • Chemistry
  • Physics

Abstract

Abstract The photoinduced [4 + 2] cycloadditions of anthracene to maleic anhydride and various maleimides yield the Diels–Alder adducts in high (chemical) yields. Analysis of the efficiency of these photoreactions as a function of the dienophile concentration leads to limiting quantum efficiencies of Φ = 0.014 and Φ = 0.16 for maleic anhydride and N-(pentafluorophenyl)maleimide, respectively. Picosecond time-resolved spectroscopy reveals the one-electron transfer from excited (singlet) anthracene to the dienophile acceptor (resulting in the formation of anthracene cation radical and dienophile anion radical) as the critical step prior to cycloaddition. Competition between coupling, back-electron transfer and dissociation of the ion-radical pair which depends on the solvent polarity and the presence of added (inert) salt, limits the quantum yields of adduct formation.

There are no comments yet on this publication. Be the first to share your thoughts.