Application of MCD spectroscopy and TD-DFT to nonplanar core-modified tetrabenzoporphyrins: Effect of reduced symmetry on nonplanar porphyrinoids

John Mack, Masaru Bunya, Yusuke Shimizu, Hiroki Uoyama, Naoki Komobuchi, Tetsuo Okujima, Hidemitsu Uno, Satoshi Ito, Martin J. Stillman, Noboru Ono, Nagao Kobayashi

Research output: Contribution to journalArticlepeer-review

49 Citations (Scopus)

Abstract

The optical spectra of a series of core-modified tetrabenzoporphyrins were analyzed to determine the effects of core modification, ligand folding, and partial benzo substitution at the ligand periphery on the electronic structure by using magnetic circular dichroism (MCD) and NMR spectroscopy, X-ray crystallography, cyclic and differential pulse voltammetry, and TD-DFT calculations. Planar 21-carba-, 21-thia-, 21,23-dithia-, and 21-oxa-23-thiatetrabenzo[b,g,l,q]porphyrins reported previously were studied together with the previously unreported 21-oxa- and 21-carba-23-thiatetrabenzo- [b,g,l,q]porphyrins. The optical properties of these compounds are compared to those of tetrabenzo[b,g,l,q]-, 5,10,15,20-tetraphenyl-, 5,10,15,20 -tetraphenyltetrabenzo[b,g,l,q]-21-thia-, 5,10,15,20- tetraphenyltetrabenzodithia-, 5,10,15,20-tetraphenyldibenzo[g,q]-21,23-dithia-, 5,10,15,20-tetraphenyldibenzo[b,l]-21,23-dithia-, 5,10,15,20- tetraphenyltribenzo[g,q,l]-21 -thia-, and 5,10,15,20-tetraphenylbenzo[b]-21- thiaporphyrins. Michl's perimeter model and Gouterman's four-orbital model are used to conceptualize the results and to account for red shifts commonly observed in the spectral bands of non-planar porphyrinoids.

Original languageEnglish
Pages (from-to)5001-5020
Number of pages20
JournalChemistry - A European Journal
Volume14
Issue number16
DOIs
Publication statusPublished - 2008 May 29

Keywords

  • Circular dichroism
  • Density functional calculations
  • Electronic structure
  • Perimeter model
  • Porphyrinoids

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry

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