A new class of cyanine-like dyes with large bond-length alternation

Shino Ohira, Joel M. Hales, Karl J. Thorley, Harry L. Anderson, Joseph W. Perry, Jean Luc Brédas*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


Cyanines, which represent a class of charged chromophores with an odd number of 0-conjugated carbons, display unique electronic and optical properties attributed to the strong electronic delocalization and the absence of any significant carbon-carbon bond-length alternation (BLA) along their backbones. The flatness of the corresponding electronic potential makes cyanine dyes the compounds to which simple free-electron theory can be applied in the most relevant way. Recently, cations of porphyrin dimers linked by a 0-conjugated bridge with an odd number of carbons and presenting alternating single and triple bonds were shown to possess linear and nonlinear optical properties analogous to those of cyanines. Here, by using a joint theoretical and experimental approach, we demonstrate the correspondence between cyanines and the new class of alkyne carbocations, in spite of their marked difference in BLA.

Original languageEnglish (US)
Pages (from-to)6099-6101
Number of pages3
JournalJournal of the American Chemical Society
Issue number17
StatePublished - May 6 2009
Externally publishedYes

ASJC Scopus subject areas

  • Catalysis
  • General Chemistry
  • Biochemistry
  • Colloid and Surface Chemistry


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