Stereochemistry of Cobalt Porphyrins. II. The Characterization and Structure of meso-Tetraphenylporphinatobis(imidazole)cobalt(III) Acetate Monohydrate Monochloroformate,[Co(Im)2(TPP)][OAc]·H2O·CHCl3

Joseph W. Lauher, James A Ibers*

*Corresponding author for this work

Research output: Contribution to journalArticle

62 Scopus citations

Abstract

The six-coordinate Co(III) porphyrin, [Co(Im)2(TPP)][OAc]·H2O·CHCl3, was prepared accidentally and has been characterized by a complete structural analysis. The material crystallizes with two formula units in space group Ci 1-P1 of the triclinic system in a cell of dimensions a = 13.055 (8) Å, b = 17.239 (7) Å, c = 11.807 (8) Å, α = 105.94 (3)°, β = 91.97 (3)°, and γ = 107.49 (3)°. The asymmetric unit consists of two half cations, so that there are two independent cations in the cell, each with a crystallographically imposed center of symmetry. The Co-N (of imidazole) axial bond length averages 1.93 (2) Å. Comparison of the present structure with that of the Co(NH3)6 3+ion enables us to estimate a minimum approach distance of a histidine to the plane of the porphyrin ring. This minimal approach distance is an essential factor in estimating the movement of the proximal histidine group toward the mean plane of the porphyrin ring upon oxygenation of cobalt-substituted hemoglobin.

Original languageEnglish (US)
Pages (from-to)4447-4452
Number of pages6
JournalJournal of the American Chemical Society
Volume96
Issue number14
DOIs
StatePublished - Jul 1 1974

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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