title: Interconversion between [Fe4S4] and [Fe2S2] Clusters Bearing Amide Ligands.
abstract: Structural conversion of [Fe4S4] clusters into [Fe2S2] clusters has been suggested to be a fundamental process for some O2-sensing proteins. While the formation of [Fe2S2] clusters from synthetic [Fe4S4] clusters has been unprecedented, an all-ferric [Fe4S4](4+) cluster Fe4S4{N(SiMe3)2}4 (1) was found to split in the presence of pyridines, giving [Fe2S2] clusters Fe2S2{N(SiMe3)2}2(L)2 (2, L = pyridines). The structural conversion between [Fe4S4] and [Fe2S2] clusters appeared to be reversible, and the thermodynamic parameters for the equilibrium reactions between 1 + L and 2 were determined. Assembly of two [Fe2S2] clusters was also induced by chemical reductions of Fe2S2{N(SiMe3)2}2(Py)2 (Py = pyridine), and the resultant [Fe4S4] clusters [1](-) and [1](2-) were found to split into two [Fe2S2] clusters by oxidation with [Cp2Fe](+) in the presence of pyridine.
authors.affiliation: Department of Chemistry, Graduate School of Science and Research Center for Materials Science, Nagoya University , Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Tanifuji
authors.affiliation: Department of Chemistry, Graduate School of Science and Research Center for Materials Science, Nagoya University , Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.
authors.forename: Shunichi
authors.initials: S
authors.lastname: Tajima
authors.affiliation: Department of Chemistry, Graduate School of Science and Research Center for Materials Science, Nagoya University , Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Ohki
authors.affiliation: Department of Chemistry, Graduate School of Science and Research Center for Materials Science, Nagoya University , Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Tatsumi
mesh_terms: D018360:Crystallography, X-Ray; D019281:Dimerization; D004735:Energy Transfer; D019277:Entropy; D005290:Ferric Compounds / Q000737:chemistry; D007501:Iron / Q000737:chemistry*; D007506:Iron-Sulfur Proteins / Q000737:chemistry; D008024:Ligands; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D066244:Proton Magnetic Resonance Spectroscopy; D011725:Pyridines / Q000737:chemistry*; D013455:Sulfur / Q000737:chemistry*
chemical_list: D005290:Ferric Compounds; D007506:Iron-Sulfur Proteins; D008024:Ligands; D011725:Pyridines; D013455:Sulfur; D007501:Iron; D010100:Oxygen