New Approach to [FeFe]-hydrogenase Models using Aromatic Thioketones
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Daraosheh, Ahmad Q.; Apfel, Ulf-Peter; Görls, Helmar; Friebe, Christian; Schubert, Ulrich S.; El-khateeb, Mohammad; Mloston, Grzegorz; Weigand, Wolfgang
- Abstract:
- The reactions of triiron dodecacarbonyl with thiobenzophenone
(2a) and 9H-thioxanthene-9-thione (2b) were investigated
under different conditions. In the case of a 1:1 molar
ratio of triiron dodecacarbonyl and 2a or 2b, the ortho-metallated
complexes [Fe2(CO)6{μ,κ,S,SCH(C6H5)C6H4-η2}] (3a)
and [Fe2(CO)6{μ,κ,S,SCH(C6H4)–S–C6H3-η2}] (4a) were obtained
as the major products, respectively. In contrast, the
treatment of triiron dodecacarbonyl with an excess of 2a or
2b afforded [Fe2(CO)6{μ-SCH(C6H5)C6H4S-μ}] (3b) and
[Fe2(CO)6{μ-SCH(C6H4)–S–C6H3S-μ}] (4b), respectively,
which are both bioinspired models for the active site of
[FeFe]-hydrogenase. In addition to these complexes, the two
reactions afforded [Fe2(CO)6{μ-SC(C6H5)2S-μ}] (3c) and [Fe2(CO)6{μ-SC(C6H4–S–C6H4)S-μ}] (4c). Furthermore, [{Fe2-
(CO)6{μ-SCH(C6H5)2}}2(μ4-S)] (3d) was isolated from the reaction
of Fe3(CO)12 with 2a. The molecular structures of all
of the new complexes were determined from the spectroscopic
and analytical data and the crystal structures for 3c,
3d, 4b, and 4c were obtained. A plausible mechanism for the
formation of the isolated complexes that involves dithiirane
derivatives as the key intermediates is proposed. Herein,
thioketones 2a and 2b act as sulfur transfer reagents. The
electrochemical experiments showed that complex 3b behaves
as a catalyst for the electrochemical reduction of protons
from acetic acid.
- Year:
- 2012
- Type of Publication:
- Article
- Keywords:
- Bioinorganic chemistry; Enzyme mimics; Hydrogenase models; Electrochemistry; Sulfur heterocycles; Thioketones; Iron
- Journal:
- European Journal of Inorganic Chemistry
- Volume:
- 2
- Pages:
- 318 - 326