title: Four-coordinate iron(II) porphyrinates: electronic configuration change by intermolecular interaction.
abstract: The syntheses and structures of three four-coordinate iron(II) porphyrinates are reported. The three derivatives are tetraarylporphyrin species, where the aryl is either phenyl, p-methylphenyl, or p-methoxyphenyl. One of these derivatives, that of tetraphenylporphyrin, Fe(TPP), is a new crystalline phase that is distinct from the earlier reported phase (Collman, J. P.; et al. J. Am. Chem. Soc. 1975, 97, 2676). This new phase of Fe(TPP) has a very saddled porphyrin core; the prior phase was ruffled. The iron atom has close interactions (approximately 3.10 A) with two pyrrole Cb-Cb bonds above and below the porphyrin plane. Mössbauer spectra and magnetic susceptibility measurements, different for the two phases, provide strong evidence that the two phases of Fe(TPP) have distinct electronic structures that originate from intermolecular interactions.
authors.affiliation: Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA.
authors.forename: Chuanjiang
authors.initials: C
authors.lastname: Hu
authors.forename: Bruce C
authors.initials: BC
authors.lastname: Noll
authors.forename: Charles E
authors.initials: CE
authors.lastname: Schulz
authors.forename: W Robert
authors.initials: WR
authors.lastname: Scheidt
mesh_terms: D003460:Crystallization; D004583:Electrons; D005296:Ferrous Compounds / Q000737:chemistry*; D007501:Iron; D008280:Magnetics; D008665:Metalloporphyrins / Q000737:chemistry*; D044367:Phase Transition; D011166:Porphyrins; D015204:Spectroscopy, Mossbauer
chemical_list: D005296:Ferrous Compounds; D008665:Metalloporphyrins; D011166:Porphyrins; C409084:tetraphenylporphyrin; D007501:Iron