The origin of the halogen effect on the phthalocyanine green pigments

Sang Uck Lee, Jong Chan Kim, Hiroshi Mizuseki, Yoshiyuk Kawazoe

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20 Citations (Scopus)


The structure and the electronic and optical properties of halo-genated copper-phthalocyanine (nα,mβ(Hal)-CuPc) molecules are investigated, according to the variation in the substituted halogen-atom species (Hal = Cl or Br) at the α and β positions of isoindole ring with different numbers (n and m = 0, 4, 8, or 16). Our results show that the halogen effect mainly results from a structural deformation rather than caused by electronic effects. A nonplanar deformation of the phthalocyanine chromophore of the nα,mβ(Hal)-CuPc molecule causes a significant change only in the HOMO and HOMO-1 levels, rather than in the LUMO levels, which leads to the appearance of a green color arising from the large red-shifts of the Soret and Q bands. The present result may serve as an important reference point for designing novel halogen-free green pigments, in accordance with the environmental regulations for the restriction of hazardous substances (RoHS) in electronic and electrical devices.

Original languageEnglish
Pages (from-to)1341-1346
Number of pages6
JournalChemistry - An Asian Journal
Issue number6
Publication statusPublished - 2010 Jun 1


  • Absorption
  • Density functional calculations
  • Dyes/ pigments
  • Halogenation
  • Phthalo-cyanines

ASJC Scopus subject areas

  • Biochemistry
  • Organic Chemistry


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