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'Dinuclear Iron III Complex' in keywords
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1997 (1)
1994 (1)
1Author    Sayo Itoa, Takashi Okuno3, Hiroki Itoha, Shigeru Ohbab, Hideaki Matsushima0, Tadashi Tokiic, Yuzo NishidaRequires cookie*
 Title    Chemical Basis for High Activity in Oxygenation of Cyclohexane Catalyzed by Dinuclear Iron(III) Complexes with Ethereal Oxygen Containing Ligand and Hydrogen Peroxide System  
 Abstract    The crystal structures of two binuclear iron(III) complexes with linear u-oxo bridge, Fe20 Cl2 (tfpy)2 (C1 0 4)2 -2 C H 3 CN and Fe2 0 Cl2(epy)2 (C1 0 4) 2 were determined, where (tfpy) and (epy) represent N,N-bis(2-pyridylmethyl)-tetrahydrofurfurylamine and N,N-bis(2-pyri-dylmethyl)-2-ethoxyethylamine, respectively. Their structural features are essentially the same as that of the corresponding linear binuclear complex with (tpa)-complex, Fe2O C l2-(tpa)2(C104)2, where (tpa) is tris(2-pyridylmethyl)amine; the ligands (tfpy) and (epy) act as a tetradentate tripod-like ligand, and Fe-O (ethereal oxygen atom; these are located at the rram-position of bridging oxo-oxygen atom) distances are 2.209(4) and 2.264(2) A for (tfpy) and (epy) compounds, respectively. These two (tfpy) and (epy) complexes exhibited much higher activity for the oxygenation of cyclohexane in the presence of hydrogen peroxide than that of the (tpa) complex. In contrast to this, the former two complexes exhibit negligible activity for the decomposition of hydrogen peroxide, whereas the catalase-like function of the (tpa) compound is remarkable. These are indicating that an active species for oxygenation of cyclohexane, which is assumed to be an iron(III)-hydroperoxide adduct with //'-coordina­ tion mode, should be different from that is operating for decomposition of hydrogen perox­ ide; for the latter case formation of a (//-//1://'-peroxo)diiron(III) species being stressed. The E H M O calculation showed that electronic interaction between the monodentate hydroperox­ ide adduct of the binuclear iron(IIl)-(tfpy) compound and the tetrahydrofuran ring of the ligand system may lead to facile peroxide-tetrahydrofuran linkage formation, and the interac­ tion described above should promote the 0 -0 cleavage of the peroxide ion heterolytically. Based on these discussions, it was concluded that heterolytic 0 -0 bond cleavage of the iron(III)-hydroperoxide adduct caused by electronic interaction with organic moiety contain­ ing an ethereal-oxygen and by approach of the substrate which donates electron to the perox­ ide adduct should play an important role in producing a high-valent iron-oxo species in these systems. In the case of (tpa) complex, formation of a hydroperoxide adduct linking with the ligand system seems to be unfavorable because of both the steric and electronic reasons. 
  Reference    Z. Naturforsch. 52b, 719—727 (1997); received March 6 1997 
  Published    1997 
  Keywords    Ethereal Oxygen, Cyclohexane, Dinuclear Iron(III) Complexes 
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 TEI-XML for    default:Reihe_B/52/ZNB-1997-52b-0719.pdf 
 Identifier    ZNB-1997-52b-0719 
 Volume    52 
2Author    Z. NaturforschRequires cookie*
 Title    Structure and Magnetic Properties of a Dinuclear Complex with Iron(III) in Octahedral and Pyramidal Coordination  
 Abstract    [FeL(M eO H)C l]2 (L = N-(2-hydroxyphenyl)salicylaldimine) was synthesized and its crystal structure determ ined, [C27H 20N 2O5Cl2Fe2], monoclinic, space group P 2 a/c, a = 9.528(1), b = 7.684(1), c = 18.365(2) Ä , ß = 109.83(1)°, V = 1264.8 Ä 3, Z = 2. Two identical [FeL(M eOH)Cl] fragments, related by an inversion centre, are combined by the two bridging O atoms, to form a binuclear unit. The iron(III) centers are separated by 3.163(2) A and weakly antiferro-magnetically coupled (J = -8 .0 (1) cm -1), which follows from temperature -dependent mag­ netic susceptibility m easurements in the range 4.2 to 288 K. The effective magnetic moment per iron(III) is /ueff = 7.4 /uB at 288 K. 
  Reference    Z. Naturforsch. 49b, 1239—1242 (1994); received March 28 1994 
  Published    1994 
  Keywords    Dinuclear Iron(III) Complex, X-Ray, Structure, Magnetic Properties, Antiferromagnetic Coupling 
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 TEI-XML for    default:Reihe_B/49/ZNB-1994-49b-1239.pdf 
 Identifier    ZNB-1994-49b-1239 
 Volume    49