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Digitale Medien

Synthesis and characterization of the asymmetrically coordinated dinuclear complex [{L(Ph2acac)FeIII}(μ-O){FeIII(Cl4-cat)L}](ClO4) and its one-electron reduced and oxidized forms. Models for dinuclear non-heme active sites (1998)

Müller, Michael ; Weyhermüller, Thomas ; Bill, Eckhard ; [weitere]

Springer

JBIC 3 (1998), S. 96-106

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ISSN: 1432-1327

Schlagwort(e): Key words Dinuclear iron complexes ; Non-heme iron complexes ; Mössbauer spectroscopy ; Mixed-valent iron complexes

Quelle: Springer Online Journal Archives 1860-2000

Thema: Biologie , Chemie und Pharmazie

Notizen: Abstract The asymmetrically coordinated complex [{L(Ph2acac)FeIII}(μ-O){FeIII(Cl4-cat)L}](BPh4)·1.5toluene has been synthesized and structurally characterized (Ph2acac–=1,3-diphenylpropane-1,3-dionate, Cl4-cat2–=tetrachlorocatecholate, L=1,4,7-trimethyl-1,4,7-triazacyclononane). This species can be electrochemically oxidized and reduced by one electron, respectively, yielding two species which both have an S=1/2 ground state. It is shown that the oxidation is ligand-centered, affording a coordinated semiquinonate(1–) ligand with S=1/2 which is antiferromagnetically coupled to a high-spin FeIII ion (S=5/2) yielding an S=2 state which, in turn, is antiferromagnetically coupled (through the oxo bridge) to the second high-spin FeIII ion (S=5/2) yielding the observed S=1/2 ground state. In contrast, the reduction is metal-centered generating a mixed-valent species with an [FeIII-O-FeII]3+ core; intramolecular antiferromagnetic coupling again produces an S=1/2 ground state. The symmetrical complex [{LFeIII(Ph2acac)}2(μ-O)](ClO4)2 has also been synthesized, as have the mononuclear species [LFeII(Ph2acac)Cl] and [LFeIII(aacac)Cl](ClO4)·1 mesitylene [aacac–=3-(9-anthryl)acetylacetonate(1–)], all of which have been characterized by X-ray crystallography. The magnetism, the Mössbauer-, EPR-, and UV-VIS-spectra and the electrochemistry of complexes are reported.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/s007750050211

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Digitale Medien

Synthese von N-phenolat-funktionalisierten Makrocyclen des 1,4,7-Trazacyclononans sowie des 1-Oxa-4,7-diazacyclononans und ihre Komplexchemie mit Eisen(III)Herrn Professor Alois Hass zum 60. Geburtstage am 3. Januar 1992 gewidmet (1992)

Flassbeck, C. ; Wieghardt, K.

Weinheim : Wiley-Blackwell

Zeitschrift für anorganische Chemie 608 (1992), S. 60-68

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ISSN: 0044-2313

Schlagwort(e): Iron(III) ; coordination chemistry ; electronic spectra ; Chemistry ; Inorganic Chemistry

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie

Beschreibung / Inhaltsverzeichnis: Synthesis of N-Phenolate-functionalized Macrocycles of 1,4,7-Triazacyclononane and of 1-Oxa-4,7-diazacyclononane and their Coordination Chemistry with Iron(III)Six new tetra- or pentadentate, N-phenolate functionalized, pendant, arm macrocyclic containing a 1,4,7-traizacyclononane or a 1-oxa-4,7-diazacyclononane backbone have been synthesized and their coordination chemistry with iron(III) has been investigated. Electronic spectra of these octahedral high-spin FeIII complexes have been measured. The Phenolate-to-iron(III) charge transfer band has been studied as a function of the number of coordinated phenolate residues (1,2, or 3) and of the substituents at the phenolate arms. The dinuclear complex [L27Fe2(μ-O2CPh)](C1O)4)3 has been synthesized where the two FeIII centres are connected via a symmetric μ-benzoato bridge and two phenolate oxygen atoms (L7 = N-(2-hydroxybenzyl)-1,4,7-triazacyclononane).

Notizen: Ausgehend von den neungliedrigen Makrocyclen 1,4,7-Triazacylononan und 1-Oxa-4,7-diazacyclononan wurden sechs neue, fünf- und vierzähnige N-phenolat-funktionalisierte Liganden synthetisiert und ihre Komplexchemie mit Eisen(III) untersucht. Die UV-vis Spektren der oktaedrischen, high-spin Eisen(III)-Komplexe wurden vermessen, und die Phenolat→Eisen(III) Charge-Transfer-Bande als Funktion der Anzahl koordinierter Phenolatliganden (1, 2 oder 3) und der Substituenten am Phenolatrest studiert. Der dinukleare Komplex [L27Fe2(μ-O2CPh)](C1O4)3, in dem die beiden FeIII- Zentren über eine symmetrische Benzoatbücke sowie über verbrückende Phenolatsauerstoffatome miteinander verknüpft sind, wurde ebenfalls hergestellt (L7 = N-(2-Hydroxybenzy1-1,4,7-Triazaxyxlononan.

Zusätzliches Material: 4 Ill.