title: Low-spin pseudotetrahedral iron(I) sites in Fe₂(μ-S) complexes.
abstract: Fe(I) centers in iron-sulfide complexes have little precedent in synthetic chemistry despite a growing interest in the possible role of unusually low valent iron in metalloenzymes that feature iron-sulfur clusters. A series of three diiron [(L3Fe)2(μ-S)] complexes that were isolated and characterized in the low-valent oxidation states Fe(II)-S-Fe(II), Fe(II)-S-Fe(I), and Fe(I)-S-Fe(I) is described. This family of iron sulfides constitutes a unique redox series comprising three nearly isostructural but electronically distinct Fe2(μ-S) species. Combined structural, magnetic, and spectroscopic studies provided strong evidence that the pseudotetrahedral iron centers undergo a transition to low-spin S=1/2 states upon reduction from Fe(II) to Fe(I). The possibility of accessing low-spin, pseudotetrahedral Fe(I) sites compatible with S(2-) as a ligand was previously unknown.
authors.affiliation: Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125 (USA).
authors.forename: John S
authors.initials: JS
authors.lastname: Anderson
authors.forename: Jonas C
authors.initials: JC
authors.lastname: Peters
mesh_terms: D007501:Iron / Q000737:chemistry*; D007506:Iron-Sulfur Proteins / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure
chemical_list: D007506:Iron-Sulfur Proteins; D007501:Iron
keywords: diiron complexes; hydrogenases; iron-sulfur clusters; low-spin iron(I); nitrogenases
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