title: Silicon-Heteroaromatic [FeFe] hydrogenase model complexes: insight into protonation, electrochemical properties, and molecular structures.
abstract: To learn from Nature how to create an efficient hydrogen-producing catalyst, much attention has been paid to the investigation of structural and functional biomimics of the active site of [FeFe]-hydrogenase. To understand their catalytic activities, the μ-S atoms of the dithiolate bridge have been considered as possible basic sites during the catalytic processes. For this reason, a series of [FeFe]-H2 ase mimics have been synthesized and characterized. Different [FeFe]-hydrogenase model complexes containing bulky Si-heteroaromatic systems or fluorene directly attached to the dithiolate moiety as well as their mono-PPh3 -substituted derivatives have been prepared and investigated in detail by spectroscopic, electrochemical, X-ray diffraction, and computational methods. The assembly of the herein reported series of complexes shows that the μ-S atoms can be a favored basic site in the catalytic process. Small changes in the (hetero)-aromatic system of the dithiolate moiety are responsible for large differences in their structures. This was elucidated in detail by DFT calculations, which were consistent with the experimental results.
authors.affiliation: Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität, Humboldtstraße 8, 07743 Jena (Germany), Fax: (+49) 3641-948102.
authors.forename: Roman
authors.initials: R
authors.lastname: Goy
authors.forename: Luca
authors.initials: L
authors.lastname: Bertini
authors.forename: Helmar
authors.initials: H
authors.lastname: Görls
authors.forename: Luca
authors.initials: L
authors.lastname: De Gioia
authors.forename: Jean
authors.initials: J
authors.lastname: Talarmin
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Zampella
authors.forename: Philippe
authors.initials: P
authors.lastname: Schollhammer
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Weigand
mesh_terms: D004563:Electrochemistry / Q000379:methods*; D006864:Hydrogenase / Q000737:chemistry*; D006865:Hydrogenation; D008958:Models, Molecular; D015394:Molecular Structure; D012825:Silicon / Q000737:chemistry*
chemical_list: D006864:Hydrogenase; D012825:Silicon
keywords: density functional calculations; enzyme models; hydrogen; protonation; sulfur