An investigation into the initial degradation steps of four major dye chromophores: study of their one-electron oxidation and reduction by EPR, ENDOR, cyclic voltammetry, and theoretical calculations

Tsvetanka Stanoeva; Dmytro Neshchadin; Georg Gescheidt; Jiri Ludvik; Barbora Lajoie; Stephen N Batchelor

doi:10.1021/jp053536l

An investigation into the initial degradation steps of four major dye chromophores: study of their one-electron oxidation and reduction by EPR, ENDOR, cyclic voltammetry, and theoretical calculations

J Phys Chem A. 2005 Dec 15;109(49):11103-9. doi: 10.1021/jp053536l.

Authors

Tsvetanka Stanoeva¹, Dmytro Neshchadin, Georg Gescheidt, Jiri Ludvik, Barbora Lajoie, Stephen N Batchelor

Affiliation

¹ Institute of Physical and Theoretical Chemistry, Graz University of Technology, Technikerstrasse 4/I, 8010 Graz, Austria.

PMID: 16331892
DOI: 10.1021/jp053536l

Abstract

The degradation of dyes is frequently initiated by one-electron oxidation or reduction; however, relatively little is known about the initially formed radicals. Acid Green 25 (AG25), Crystal Violet (CVI), Methylene Blue (MB), and Acid Orange 7 (AO7), representing paradigms of four types of commercial organic dyes, were therefore investigated in terms of their redox behavior. Their redox potentials in MeCN and buffered aqueous solutions were determined by cyclic voltammetry. The structures of the one-electron reduced and oxidized dyes were established by EPR spectroscopy and by theoretical calculations on the density functional level of theory.