title: Tuning the oxidative power of free iron-sulfur clusters.
abstract: The gas-phase reactions between a series of di-iron sulfur clusters Fe2Sx+(x = 1-3) and the small alkenes C2H4, C3H6, and C4H8have been investigated by means of Fourier-transform ion-cyclotron resonance mass spectrometry. For all studied alkenes, the reaction efficiency is found to increase in the order Fe2S+< Fe2S2+< Fe2S3+. In particular, Fe2S+and Fe2S2+only form simple association products, whereas the sulfur-rich Fe2S3+is able to dehydrogenate propene and 2-butene via desulfurization of the cluster and formation of H2S. This indicates an increased propensity to induce oxidation reactions, i.e. oxidative power, of Fe2S3+that is attributed to an increased formal oxidation state of the iron atoms. Furthermore, the ability of Fe2S3+to activate and dissociate the C-H bonds of the alkenes is observed to increase with increasing size of the alkene and thus correlates with the alkene ionization energy.
authors.affiliation: Institut für Oberflächenchemie und Katalyse, Universität Ulm, Albert-Einstein-Allee 47, 89069 Ulm, Germany. sandra.lang@uni-ulm.de and Institut für Chemieingenieurwesen, Universität Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany.
authors.forename: Sandra M
authors.identifier: http://orcid.org/0000-0001-7851-0850
authors.initials: SM
authors.lastname: Lang
authors.affiliation: Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany.
authors.forename: Shaodong
authors.initials: S
authors.lastname: Zhou
authors.affiliation: Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany.
authors.forename: Helmut
authors.identifier: http://orcid.org/0000-0002-3369-7997
authors.initials: H
authors.lastname: Schwarz