Structural Characterization of OC3OPor Capped Porphyrins: H2(OC3OPor), Fe(OC3OPor)(Cl), Fe(OC3OPor)(CO)(1-MeIm), and Fe(OC3OPor)(CO)(1,2-Me2Im)

Carla Slebodnick, Michelle L. Duval, James A. Ibers*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

24 Scopus citations

Abstract

The sterically encumbered OC3OPor system consists of a 1,2,4,5-substituted benzene cap with five-atom arms of the type -O(CH2)3O- linking the benzene cap to the ortho positions of 5,10,15,20-tetraphenylporphyrin. The structures of the following compounds have been determined by single-crystal X-ray diffraction methods: H2(OC3OPor) (1), Fe(OC3OPor)(Cl) (2), Fe(OC3OPor)(CO)(1-MeIm) (3), and Fe(OC3OPor)(CO)(1,2-Me2Im) (4). Structures 1-3 pack as one crystallographically independent porphyrin with solvate molecules, whereas structure 4 packs with half of a crystallographically independent porphyrin molecule and a solvate molecule. In compound 2 the Cl ligand is bound to the Fe center on the unprotected side of the porphyrin. In 3 and 4, which represent R-state (relaxed) and T-state (tense) models for hemoglobin, respectively, CO is bound underneath the cap and either 1-MeIm (3) or 1,2-Me2Im (4) is bound to the sixth coordination site, opposite the CO and outside the cap. The bulkier 1,2-Me2Im in 4 forces the Fe atom 0.10 Å out of the mean nitrogen plane toward the 1,2-Me2Im ligand. In 3, where the base is less bulky, the Fe atom lies 0.06 Å out of the plane toward the CO ligand. The cap-to-porphyrin distance increases approximately 0.8 Å to accommodate CO, from 4.74 and 4.65 Å in 1 and 2, respectively, to 5.55 and 5.59 Å in 3 and 4, respectively. The Fe-C-O angle is 173.9(7)° in 3 and is constrained by symmetry to be 180° in 4.

Original languageEnglish (US)
Pages (from-to)3607-3613
Number of pages7
JournalInorganic chemistry
Volume35
Issue number12
DOIs
StatePublished - Jan 1 1996

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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