Re-examination of the emission properties of alkoxy- and thioalkyl-substituted phthalocyanines

John Mack, Nagao Kobayashi, Martin J. Stillman

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)


The role of n → π* transitions in the optical spectra of alkoxy- and thioalkyl-substituted phthalocyanines with peripheral substituents is re-examined, based on a detailed analysis of UV-visible absorption, magnetic circular dichroism (MCD) and fluorescence emission spectral data and the results of density functional theory (DFT) and time dependent-density functional theory (TD-DFT) calculations. The nπ* excited states associated with the lone pairs of the peripheral heteroatoms have been proposed as the origin of a second emission peak observed in the 400-600nm region, which has been assigned as S2 emission, since S1 fluorescence associated with the Q band is observed in the near IR region. Our results demonstrate that emission from a photodecomposition product can fully account for this violet emission and that reports of S2 emission for peripherally substituted phthalocyanines and porphyrazines should be treated with caution.

Original languageEnglish
Pages (from-to)310-317
Number of pages8
JournalJournal of Inorganic Biochemistry
Issue number3
Publication statusPublished - 2010 Mar
Externally publishedYes


  • MCD spectroscopy
  • Phthalocyanines
  • S2 emission
  • TD-DFT calculations

ASJC Scopus subject areas

  • Biochemistry
  • Inorganic Chemistry


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