The ultraviolet absorption spectra of some chlorinated biphenyls

James D. MacNeil, Stephen Safe, Otto Hutzinger

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


The UV spectra of 29 chlorobiphenyls have been examined. With increasing chloro substitution in which there are less than two chlorine groups ortho to the Ph-Ph bond the λmax values for the κ band (attributed to conjugation between the two phenyl rings) are shifted to longer wavelengths and for the more highly substituted chlorobiphenyls there is also a bathochromic shift of the main band (due to the benzenoid skeleton). Introduction of two or more chlorine atoms ortho to the Ph-Ph bond results in a hipsochromic shift of κ band and diminished e{open} value due to steric inhibition of resonance between the two phenyl rings. The sterically hindered chlorobiphenyls and the more highly chlorinated Aroclors also exhibit a series of low-intensity finestructured absorption maxima between 268-302 nm. The UV spectra of chlorobiphenyls are particularly diagnostic with respect to the degree of substitution at the 2, 2′, 6 and 6′ positions and can be used in the structural analysis of separated chlorobiphenyls. The data may also aid in correlating the photochemical reactivities.

Original languageEnglish (US)
Pages (from-to)66-77
Number of pages12
JournalBulletin of Environmental Contamination and Toxicology
Issue number1
StatePublished - Jan 1976

ASJC Scopus subject areas

  • Toxicology
  • Pollution
  • Health, Toxicology and Mutagenesis


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