Crystal structure of a polymorph of μ-oxido-bis[(5,10,15,20-tetraphenylporphyrinato)iron(III)]

Abstract

The title compound, [Fe2(C44H28N4O)2O], was obtained as a by-product during the synthesis of FeIII tetraphenylporphyrin perchlorate. It crystallizes as a new polymorphic modification in addition to the orthorhombic form previously reported [Hoffman et al. (1972). J. Am. Chem. Soc. 94, 3620–3626; Swepston & Ibers (1985) Acta Cryst. C41, 671–673; Kooijmann et al. (2007). Private Communication (refcode 667666). CCDC, Cambridge, England]. In its crystal structure, the two crystallographically independent FeIII cations are coordinated in a square-planar environment by the four N atoms of a tetraphenylporphyrin ligand. The FeIII-tetraphenylporphyrine units are linked by a μ2-oxido ligand into a dimer with an Fe—O—Fe angle close to linearity. The final coordination sphere for each FeIII atom is square-pyramidal with the μ2-oxido ligand in the apical position. The crystal under investigation consisted of two domains in a ratio of 0.691 (3): 0.309 (3).

Keywords

• crystal structure
• ferric porphyrin
• dimer
• polymorphism
• twinning