Meso-aryl phenanthroporphyrins: Synthesis and spectroscopic properties

Hai Jun Xu, John Mack, Ana B. Descalzo, Zhen Shen, Nagao Kobayashi, Xiao Zeng You, Knut Rurack

Research output: Contribution to journalArticle

38 Citations (Scopus)

Abstract

The successful synthesis of tetraphenyltetraphenanthroporphyrin (TPTPhenP; 5a) in 2006 under modified Rothemund-Lindsey conditions yielded a tetraphenyl porphyrinoid with a B band redshifted to an unprecedented 576 nm. Radially symmetric fused-ring expansion of tetraphenylporphyrin with phenanthrene moieties results in very deep saddling due to steric crowding and very marked redshifts of the Q and B (or Soret) porphyrinoid absorption bands. The extent to which the TPTPhenP structure can be further modified is explored, and the optical properties of TPTPhenPs are analyzed based on a perimeter model approach that makes use of time-dependent DFT calculations and magnetic circular dichroism spectroscopy and also based on a detailed analysis of the fluorescence emission. Attempts to introduce substituents at the ortho and meta positions of the meso-phenyl groups and to insert a central metal proved unsuccessful. The synthesis of a series of TPTPhenPs with strong electron-withdrawing (-CN, -NO2) and -donating (-CH3, -N(CH3)2) substituents at the para positions of the meso-phenyl rings is reported. Marked redshifts of the main spectral bands were consistently observed. The most pronounced spectral changes were observed with -N(CH3)2 groups (5i) due to a marked destabilization of the HOMO, which has large MO coefficients on the meso-carbon atoms. Protonation of 5i at both the ligand core and at the -N(CH3)2 groups resulted in unprecedented Q00 band absorption at wavelengths greater than 1200 nm.

Original languageEnglish
Pages (from-to)8965-8983
Number of pages19
JournalChemistry - A European Journal
Volume17
Issue number32
DOIs
Publication statusPublished - 2011 Aug 1

Keywords

  • charge transfer
  • circular dichroism
  • dyes/pigments
  • porphyrinoids
  • protonation

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry

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    Xu, H. J., Mack, J., Descalzo, A. B., Shen, Z., Kobayashi, N., You, X. Z., & Rurack, K. (2011). Meso-aryl phenanthroporphyrins: Synthesis and spectroscopic properties. Chemistry - A European Journal, 17(32), 8965-8983. https://doi.org/10.1002/chem.201002596