title: Steric effect of the dithiolato linker on the reduction mechanism of [Fe2(CO)6{μ-(XCH2)2CRR'}] hydrogenase models (X = S, Se).
abstract: Studying the redox features of the [FeFe]-hydrogenase models is essential for understanding the function of the H cluster. The reduction of the [FeFe]-hydrogenase models of the type [Fe2(CO)6{μ-(XCH2)2E}] (X = S, Se) is described to occur either via sequential transfer of two electrons at and for the first and the second reduction steps, respectively, where , or via transfer of two electrons at the same applied potential due to potential inversion of the two reduction steps, i.e.. Typically, the phenomenon of potential inversion is observed when a structural change intervenes in the cathodic process stabilizing the reduced species. In this report, we investigate the mechanism of the cathodic process of series of models [Fe2(CO)6{μ-(XCH2)2E}] (X = S or Se and E = CH2, CHMe or CMe2) applying cyclic voltammetry. The studies herein show the remarkable influence of the steric bulk of E toward the cathodic process, such that only complexes with E = CMe2 are reduced with inverted potentials due to occurrence of an ECE mechanism (E = electrochemical process, C = chemical process) of reduction. Moreover, we describe the catalytic behaviour of these models toward reduction of protons using acetic acid, AcOH, as a proton source.
authors.affiliation: Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität Jena, Humboldtstrasse 8, D-07743 Jena, Germany. wolfgang.weigand@uni-jena.de.
authors.forename: Ralf
authors.initials: R
authors.lastname: Trautwein
authors.affiliation: Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität Jena, Humboldtstrasse 8, D-07743 Jena, Germany. wolfgang.weigand@uni-jena.de.
authors.forename: Laith R
authors.initials: LR
authors.lastname: Almazahreh
authors.affiliation: Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität Jena, Humboldtstrasse 8, D-07743 Jena, Germany. wolfgang.weigand@uni-jena.de.
authors.forename: Helmar
authors.initials: H
authors.lastname: Görls
authors.affiliation: Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität Jena, Humboldtstrasse 8, D-07743 Jena, Germany. wolfgang.weigand@uni-jena.de and Jena Center of Soft Matter (JCSM), Philosophenweg 7, D-07743 Jena, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Weigand