An electrically conducting crystal composed of an octahedrally ligated porphyrin complex with high-spin iron(iii). Issue 12 (8th February 2018)

• Record Type: Journal Article
• Authors: Nishi, Miki; Ishii, Ryuta; Ikeda, Mitsuo; Hanasaki, Noriaki; Hoshino, Norihisa; Akutagawa, Tomoyuki; Sumimoto, Michinori; Matsuda, Masaki
• Is Part Of: Dalton transactions. Volume 47:Issue 12(2018)
• Page Start: 4070
• Page End: 4075
• Publication Date: 2018-02-08
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c7dt04649a
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : A porphyrin-based electrically conducting crystal with high-spin iron(iii ) was designed and synthesised. Abstract : A porphyrin-based octahedrally ligated complex with high-spin iron(iii ) was designed, and the resulting electrically conducting crystal TPP[Fe III (tbp)Br2 ]2 (TPP = tetraphenylphosphonium and tbp = tetrabenzoporphyrin) was synthesised. Although TPP[Fe(tbp)Br2 ]2 was isostructural to the reported TPP[Fe(Mc)L2 ]2 systems (Mc = macrocyclic ligands such as phthalocyanine (Pc) or tbp; and L = CN, Cl, or Br), the bond lengths between Fe and ligands in the [Fe(tbp)Br2 ] unit were evidently longer than those in the other units, because of the different spin states of Fe: high-spin in TPP[Fe(tbp)Br2 ]2 and low-spin in others. The magnetic anisotropy observed in the low-spin state vanished when the Fe is in the high-spin state. Based on reports for Pc-based systems, the negative magnetoresistance (MR) effect for TPP[Fe(tbp)Br2 ]2 was expected to be smaller than that for TPP[Fe(tbp)(CN)2 ]2 . However, the former showed a giant negative MR effect similar to or larger than the latter, suggesting that the nature of iron is a crucial factor for the electrical properties of porphyrin-based materials.