Article ID Journal Published Year Pages File Type
1327491 Journal of Organometallic Chemistry 2009 6 Pages PDF
Abstract

Two carboxy-functionalized diiron complexes [{(μ-SCH2)2X}{Fe(CO)3}{Fe(CO)2L}] (X = NC3H7, L = Ph2PCH2CH2COOH, 4; X = CH2, L = Ph2PCH2COOH, 5) were prepared, as biomimetic models of the [FeFe] hydrogenase active site, from the CO-replacement of [{(μ-SCH2)2NC3H7}Fe2(CO)6] (1) and (μ-pdt)Fe2(CO)6 (2) by phosphine ligands in CH3CN at 40 °C, respectively. In contrast, the reaction of 1 with Ph2PCH2COOH under the same condition afforded complex [{(μ-SCH2)2NC3H7}{Fe(CO)3}{Fe(CO)2(Ph2PCH3)}] (3) with a decarboxylated phosphine ligand. The molecular structures of complexes 3–5 were determined by X-ray crystallographic analyses, which show that they have similar frameworks with the phosphine ligand on the apical position. The interesting C–H···S contacts between the methylene hydrogen atoms of the PhCH2COOH ligand and the μ-S atoms of the pdt-bridge are found in the crystal of 5. According to the experimental evidence, a plausible mechanism, via sequential phosphine coordination, N-protonation, and decarboxylation steps, is proposed for the formation of 3 and for explanation of the contrastive reactivities of the adt- (2-aza-1,3-propanedithiolato) and the pdt- (1,3-propanedithiolato) bridged diiron complexes toward decarboxylation of the Ph2PCH2COOH ligand.

Graphical abstractThe adt- (2-aza-1,3-propanedithiolato) and the pdt- (1,3-propanedithiolato) bridged diiron complexes display contrastive reactivities toward Ph2PCH2COOH. The former gave a decarboxylated Ph2PCH3-coordinate complex, while the latter afforded the carboxy-functionalized complex by usual CO-replacement.Figure optionsDownload full-size imageDownload as PowerPoint slide

Related Topics
Physical Sciences and Engineering Chemistry Inorganic Chemistry
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