Gradual change of one- and two-​photon absorption properties in solution-​Protonation of 4-​N,​N-​dimethylamino-​4'-​aminoazobenzene

Fadhil S. Kamounah, Liudmil Antonov, Kenji Kamada, Daniela Nedeltcheva, Koji Ohta

Research output: Contribution to journalJournal articleResearchpeer-review


Linear (one-photon) and nonlinear (two-photon) spectral properties of 4-N,N-dimethylamino-4′-aminoazobenzene have been investigated under protonation in DMSO/water solvent mixtures. Observed spectral changes have been discussed in terms of ammonium–azonium tautomerism. The corresponding tautomeric constants have been determined for the first time for such kind of tautomeric equilibria. The process of protonation leads to changes of the two-photon absorption properties, suggesting that such process could be used as a tool for change of third-order nonlinear optical activity in solution.
Original languageEnglish
Article number16
JournalJournal of Photochemistry and Photobiology, A: Chemistry
Issue number2-3
Pages (from-to)274-282
Number of pages9
Publication statusPublished - 2006
Externally publishedYes


  • Aminoazobenzenes
  • Protonation
  • Ammonium–azonium tautomersim
  • Two-photon absorption
  • Femtosecond Z-scan technique

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