Models of the oxidized forms of polyiron oxo proteins: synthetic routes to (μ-oxo)bis(μ-carboxylato)diiron(III) complexes with neutral monodentate and bidentate capping ligands
✍ Scribed by Kingsley L. Taft; Axel Masschelein; Shuncheng Liu; Stephen J. Lippard; Diana Garfinkel-Shweky; Avi Bino
- Publisher
- Elsevier Science
- Year
- 1992
- Tongue
- English
- Weight
- 486 KB
- Volume
- 198-200
- Category
- Article
- ISSN
- 0020-1693
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✦ Synopsis
Two (k-oxo)bis(p-carboxylato)diiron (III) complexes with neutral monodentate and bidentate terminal ligands have been prepared that incorporate features of the diiron 0x0 centers in the non-heme iron proteins hemerythrin (Hr)
and the B2 subunit of ribonucleotide reductase (RRB2) that were not previously modeled. [F~O(OH,),(0,CCH,Cl)2(bpy),l(N03)2
(1) and [Fe,0(CH30H)2(0,CCH3)2(BIPhMe),l(N03)2
(2) were synthesized from the appropriate basic iron carboxylate, ferric nitrate and the bidentate nitrogen ligand bpy or BIPhMe. The molecular structures, as determined by X-ray crystallography, and the electronic spectral, Miissbauer and magnetic properties of 1 and 2 reproduce many of the physical properties of the met forms of Hr and RRB2.
A singly-bridged (p-oxo)diiron(III) complex, [Fe,O(NO,),(bpy)J (3), was also prepared from ferric nitrate and bpy. The chelating bpy and nitrate ligands afford seven-coordinate ferric centers in the centrosymmetric compound. Complex 3 serves as a synthon for the (w-oxo)bis(p-carboxylato)diiron(III) core, for the reaction of 3 with excess chloroacetic acid gives 1.