ELECTRON-TRANSFER FROM AROMATIC-COMPOUNDS TO PHENYLIODINIUM AND DIPHENYLSULFINIUM RADICAL CATIONS


YAGCI Y. , SCHNABEL W., WILPERT A., BENDIG J.

JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS, vol.90, no.2, pp.287-291, 1994 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 90 Issue: 2
  • Publication Date: 1994
  • Doi Number: 10.1039/ft9949000287
  • Title of Journal : JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS
  • Page Numbers: pp.287-291

Abstract

Phenyliodinium (I-.+) and diphenylsulfinium radical cations (II.+) have been generated by flash photolysis (lambda(inc) = 347 nm) of diphenyliodonium ions (I+) and diphenyl(4-phenylthiophenyl)sulfonium ions (II+) in acetonitrile solutions at room temperature. I-.+ and II.+ were found to undergo electron-transfer reactions with benzene derivatives resulting in the formation of radical cations of the aromatic compounds. A study involving 25 compounds including various methyl- and methoxy-benzenes, biphenyl, phenol and cresols revealed that electron transfer is independent of the ionization energy E(i) provided that the rates are encounter-controlled This applies to cases where E(1) does not exceed a critical value: E(i, crit) approximate to 820 kJ mol(-1) (I-.+) and 780 kJ mol(-1) (II.+). Bimolecular rate constants decrease with increasing E(i) in the case of aromatic compounds having ionization energies exceeding the critical values. A Marcus-inverted region was not detected.