title: Redox communication within multinuclear iron-sulfur complexes related to electronic interplay in the active site of [FeFe]hydrogenase.
abstract: The one-electron oxidations of a Fe2 complex lead to the formation of a persistent metal-stabilized thiyl radical Fe2 species, mixed-valent Fe4, and Fe8 complexes. The unpaired spin in the Fe2 radical species delocalizes over the Fe2 and the aromatic dithiolate, mostly on the terminal sulfur. The subsequent dimerization of the singly oxidized Fe2 to the Fe4 retains the partial thiyl radical character. For an analogue with less steric hindrance, the π-π stacking interaction between the dithiolato aromatic rings induces generation of the Fe8, in which process electronic structures of the species are modulated through reducing the thiyl radical to the thiolate. Electronic reorganization repeats when the Fe8 is converted to Fe4. Electronic interplay in the complexes decreases the energy gap of frontier MOs and buffers electronic impacts upon redox events. Easier accessible redox potentials and increased stability of the species are facilitated. The results demonstrate that electronic versatility of the benzenedithiolate exerts pronounced influences on electronic and coordination structure of the metal complexes.
authors.affiliation: Institute of Chemistry, Academia Sinica, Nankang, Taipei 115 (Taiwan); Molecular Science Technology Program, TIGP, Academia Sinica, Nankang, Taipei 115 (Taiwan); Department of Chemistry, National Tsing Hua University, Hsinchu 300 (Taiwan).
authors.forename: Kai-Ti
authors.initials: KT
authors.lastname: Chu
authors.forename: Yu-Chiao
authors.initials: YC
authors.lastname: Liu
authors.forename: Yi-Lan
authors.initials: YL
authors.lastname: Huang
authors.forename: Gene-Hsiang
authors.initials: GH
authors.lastname: Lee
authors.forename: Mei-Chun
authors.initials: MC
authors.lastname: Tseng
authors.forename: Ming-Hsi
authors.initials: MH
authors.lastname: Chiang
mesh_terms: D020134:Catalytic Domain; D056831:Coordination Complexes / Q000138:chemical synthesis* / Q000737:chemistry; D018360:Crystallography, X-Ray; D004563:Electrochemistry; D006864:Hydrogenase / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D007506:Iron-Sulfur Proteins / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D010084:Oxidation-Reduction; D013055:Spectrophotometry, Infrared
chemical_list: D056831:Coordination Complexes; D007506:Iron-Sulfur Proteins; D007501:Iron; C118830:iron hydrogenase; D006864:Hydrogenase
keywords: bioinorganic chemistry; hydrogen; iron; oxidation; radicals; sulfur