title: Homo-/heterotrinuclear mixed-valent oxo-centered iron/nickel clusters-Mössbauer studies on internal electron-exchange processes.
abstract: In a one-pot reaction of N-(5-methylthiazole-2-yl)-thiazole-2-carboxamide HL2 (3) with iron(II) acetate in air, the homotrinuclear heteroleptic mixed-valent oxo-centered iron cluster [Fe(II)Fe(III)O(L2)3(OAc)3] (4) was formed. Exchange of iron(II) in 4 by nickel(II) afforded the heteronuclear cluster [Ni(II)Fe(III)O(L2)3(OAc)3] (6). To obtain crystals suitable for X-ray structure analyses, in 4 and 6, the OAc- co-ligands were exchanged by OBz- ligands to give [Fe(II)Fe2(III)O(L2)3(OBz)3] (5) and [Ni(II)Fe(III)O(L2)3(OBz)3] (7). The complexes 5 and 7 are isostructural and made up of three ditopic, tridentate ligands (L2)- and three bridging benzoate co-ligands, which fix the three metal ions in the corners of a triangle with an mu3-O2- ion in the center. The mixed-valent character of 4-7, their intramolecular electron-exchange processes, and their redox properties were studied by variable-temperature Mössbauer spectroscopy and cyclic voltammetry.
authors.affiliation: Institut für Organische Chemie der Universität Erlangen-Nürnberg, Henkestrasse 42, 91054 Erlangen, Germany. saalfrank@chemie.uni-erlangen.de
authors.forename: Rolf W
authors.initials: RW
authors.lastname: Saalfrank
authors.forename: Andreas
authors.initials: A
authors.lastname: Scheurer
authors.forename: Uwe
authors.initials: U
authors.lastname: Reimann
authors.forename: Frank
authors.initials: F
authors.lastname: Hampel
authors.forename: Christian
authors.initials: C
authors.lastname: Trieflinger
authors.forename: Michael
authors.initials: M
authors.lastname: Büschel
authors.forename: Jörg
authors.initials: J
authors.lastname: Daub
authors.forename: Alfred X
authors.initials: AX
authors.lastname: Trautwein
authors.forename: Volker
authors.initials: V
authors.lastname: Schünemann
authors.forename: Veaceslav
authors.initials: V
authors.lastname: Coropceanu