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- Ballmann, Joachim, et al.
(författare)
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Secondary bonding interactions in biomimetic [2Fe-2S] clusters
- 2008
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 1520-510X .- 0020-1669. ; 47:5, s. 1586-1596
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Tidskriftsartikel (refereegranskat)abstract
- A series of synthetic [2Fe-2S] complexes with terminal thiophenolate ligands and tethered ether or thioether moieties has been prepared and investigated in order to provide models for the potential interaction of additional donor atoms with the Fe atoms in biological [2Fe-2S] clusters. X-ray crystal structures have been determined for six new complexes that feature appended Et (1(C)), OMe (1(O)), or SMe (1(S)) groups, or with a methylene group (2(C)), an ether-O (2(O)), or an thioether-S (2(S)) linking two aryl group. The latter two systems provide a constrained chelate arrangement that induces secondary bonding interactions with the ether-O and thioether-S, which is confirmed by density functional theory (DFT) calculations that also reveal significant spin density on those fifth donor atoms. Structural consequences of the secondary bonding interactions are analyzed in detail, and effects on the spectroscopic and electronic properties are probed by UV-vis, Mossbauer, and H-1 NMR spectroscopy, as well by SQUID measurements and cyclic voltammetry. The potential relevance of the findings for biological [2Fe-2S] sites is considered.
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| 3. |
- Fuchs, Michael G G, et al.
(författare)
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A five-coordinate [2Fe-2S] cluster.
- 2010
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 1520-510X .- 0020-1669. ; 49:13, s. 5853-5858
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Tidskriftsartikel (refereegranskat)abstract
- A unique [2Fe-2S] cluster (1) with genuinely five-coordinate ferric ions has been synthesized and investigated both structurally and spectroscopically. The crystal structure of 1 as well as (1)H NMR data reveal that 2,6-bis(imidazol-2-yl)pyridine binds to the [2Fe-2S] core as a tridentate capping ligand. DFT calculations showing spin density on all coordinating atoms support this finding. Cluster 1 has also been characterized by Mössbauer and UV/vis spectroscopy, mass spectrometry, cyclic voltammetry, and magnetic susceptibility measurements. Significant spectroscopic properties that make 1 distinct from conventional [2Fe-2S] clusters include a rather small quadrupole splitting of 0.43 mm/s.
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