Magnetic circular dichroism study of directly fused porphyrins

Atsuya Muranaka, Masaki Yokoyama, Yotaro Matsumoto, Masanobu Uchiyama, Akihiko Tsuda, Atsuhiro Osuka, Nagao Kobayashi

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13 Citations (Scopus)

Abstract

The magnetic circular dichroism (MCD) spectra of doubly and triply linked fused bisporphyrins (2MD and 2MT, M = Ni, Zn, Cu, Pd, and H2) and triply linked higher oligomers (3ZnT and 4ZnT) have been measured, and their Q-bands assigned based on the results of INDO/s calculations. In contrast to the Faraday A term observed for the Q(0,0) band of NiII tetraphenylporphyrin, a single positive Faraday B term was observed for the lowest energy transition of the fused systems. The calculations indicated that the molecular orbitals (MOs) of the directly fused porphyrins consist of linear combinations of the constituent monomeric MOs, and that the effect of lowering the symmetry is always larger on the lowest unoccupied molecular orbital (LUMO) than on the highest occupied molecular orbital (HOMO). On the basis of Michl's perimeter model, these features can be correlated with the observed positive MCD signs in the near infrared region. A weak absorption band at 600-700 nm for the fused dimers can be assigned to a short-axis polarized Q transition.

Original languageEnglish
Pages (from-to)171-179
Number of pages9
JournalChemPhysChem
Volume6
Issue number1
DOIs
Publication statusPublished - 2005 Jan
Externally publishedYes

Keywords

  • Chromophores
  • Electronic structure
  • Magnetic properties
  • Porphyrins
  • Semiempirical calculations

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Physical and Theoretical Chemistry

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  • Cite this

    Muranaka, A., Yokoyama, M., Matsumoto, Y., Uchiyama, M., Tsuda, A., Osuka, A., & Kobayashi, N. (2005). Magnetic circular dichroism study of directly fused porphyrins. ChemPhysChem, 6(1), 171-179. https://doi.org/10.1002/cphc.200400378