title: A sterically stabilized FeI-FeI semi-rotated conformation of [FeFe] hydrogenase subsite model.
abstract: The [FeFe] hydrogenase is a highly sophisticated enzyme for the synthesis of hydrogen via a biological route. The rotated state of the H-cluster in the [Fe(I)Fe(I)] form was found to be an indispensable criteria for an effective catalysis. Mimicking the specific rotated geometry of the [FeFe] hydrogenase active site is highly challenging as no protein stabilization is present in model compounds. In order to simulate the sterically demanding environment of the nature's active site, the sterically crowded meso-bis(benzylthio)diphenylsilane (2) was utilized as dithiolate linker in an [2Fe2S] model complex. The reaction of the obtained hexacarbonyl complex 3 with 1,2-bis(dimethylphosphino)ethane (dmpe) results three different products depending on the amount of dmpe used in this reaction: [{Fe2(CO)5{μ-(SCHPh)2SiPh2}}2(μ-dmpe)] (4), [Fe2(CO)5(κ(2)-dmpe){μ-(SCHPh)2SiPh2}] (5) and [Fe2(CO)5(μ-dmpe){μ-(SCHPh)2SiPh2}] (6). Interestingly, the molecular structure of compound 5 shows a [FeFe] subsite comprising a semi-rotated conformation, which was fully characterized as well as the other isomers 4 and 6 by elemental analysis, IR and NMR spectroscopy, X-ray diffraction analysis (XRD) and DFT calculations. The herein reported model complex is the first example so far reported for [Fe(I)Fe(I)] hydrogenase model complex showing a semi-rotated geometry without the need of stabilization via agostic interactions (Fe···H-C).
authors.affiliation: Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität, Humboldtstraße 8, 07743 Jena, Germany. wolfgang.weigand@uni-jena.de.
authors.forename: Roman
authors.initials: R
authors.lastname: Goy
authors.forename: Luca
authors.initials: L
authors.lastname: Bertini
authors.forename: Catherine
authors.initials: C
authors.lastname: Elleouet
authors.forename: Helmar
authors.initials: H
authors.lastname: Görls
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Zampella
authors.forename: Jean
authors.initials: J
authors.lastname: Talarmin
authors.forename: Luca
authors.initials: L
authors.lastname: De Gioia
authors.forename: Philippe
authors.initials: P
authors.lastname: Schollhammer
authors.forename: Ulf-Peter
authors.initials: UP
authors.lastname: Apfel
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Weigand
mesh_terms: D056831:Coordination Complexes / Q000737:chemistry*; D006864:Hydrogenase / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D007506:Iron-Sulfur Proteins / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D056831:Coordination Complexes; D007506:Iron-Sulfur Proteins; D007501:Iron; C118830:iron hydrogenase; D006864:Hydrogenase