Photochemistry of Hydroxycyclohexadienyl Radicals : 1 Methoxylated Benzenes

HANDLE Web Site Open Access

Bibliographic Information

Other Title
  • ヒドロキシシクロヘキサジエニルラジカルの光化学 : 1 メトキシ置換ベンゼン類
  • ヒドロキシシクロヘキサジエニルラジカル ノ コウカガク(1)メトキシ チカン ベンゼンルイ

Search this article

Abstract

Photochemical reactions of OH-adducts （hydroxycyclohexadienyl radicals） of a variety of methoxy substituted benzenes were investigated in aqueous solutions using the combined pulse radiolysis-laser fl ash photolysis technique. Upon laser fl ash photolysis of the OH-adducts irreversible photobleaching has been observed with quantum yields of 0.12-0.25 depending on the number and positions of methoxy substituents. Photobleaching induces formation of radical cations of methoxylated benzenes, but with rather small quantum yields of 0-0.14. Hydrogen and methyl group abstractions from methoxy groups by OH radicals have been suggested for the photolysis of OH-adducts based on the favorable enthalpy changes estimated by using bond dissociation energies of related molecules, while the former is supposed to be predominant based on the spectral observations. The infl uence of the ortho-para directing nature of methoxy groups on the photobleaching and radical cation formation quantum yields has been discussed considering the charge distributions obtained by semi-empirical molecular orbital calculations.

Journal

Keywords

Details 詳細情報について

Report a problem

Back to top