Homo-/heterotrinuclear mixed-valent oxo-centered iron/nickel clusters-Mössbauer studies on internal electron-exchange processes.
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.
Saalfrank
Rolf W
RW
Institut für Organische Chemie der Universität Erlangen-Nürnberg, Henkestrasse 42, 91054 Erlangen, Germany. saalfrank@chemie.uni-erlangen.de
Scheurer
Andreas
A
Reimann
Uwe
U
Hampel
Frank
F
Trieflinger
Christian
C
Büschel
Michael
M
Daub
Jörg
J
Trautwein
Alfred X
AX
Schünemann
Volker
V
Coropceanu
Veaceslav
V