Tetranuclear Iron Complexes Bearing Benzenetetrathiolate Bridges as Four-Electron Transformation Templates and Their Electrocatalytic Properties for Proton Reduction
2013 (English)In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 52, no 4, 1798-1806 p.Article in journal (Refereed) Published
Two tetranuclear iron-sulfur complexes, (mu,mu-pbtt)[Fe-2(CO)(6)](2) (pbtt = benzene-1,2,4,5-tetrathiolato, 3) and (mu,mu-obtt)[Fe-2(CO)(6)](2) (obtt = benzene-1,2,3,4-tetrathiolato, 4), were prepared from reaction of Fe-3(CO)(12) and the corresponding tetramercaptobenzene in THF, respectively. Complexes 5 and 6, (mu,mu-pbtt)[Fe-2(CO)(5)L-1][Fe-2(CO)(5)L-2] (L-1 = CO, L-2 = PPyr(3) (Pyr = N-pyrrolyl), 5; L-1 = L-2 = PPyr(3), 6) were obtained by controlling CO displacement of 3 with PPyr(3). Molecular structures of 3-6 were determined by spectroscopic and single-crystal X-ray analyses. All-CO Fe4S4 complexes 3 and 4 each display four-electron reduction processes in consecutive chemically reversible two-electron reduction events with relatively narrow potential spans in the cyclic voltammograms. Phosphine-substituted Fe4S4 complexes 5 and 6 exhibit two consecutive two-electron reduction events, which are not fully reversible. The electrocatalytic properties of 3 and 4 for proton reduction were studied using a series of carboxylic acids of increasing strength (CH3COOH, CH2ClCOOH, CHCl2COOH, CCl3COOH, and CF3COOH). The mechanisms for electrochemical proton reduction to hydrogen catalyzed by complex 3 as a function of acid strength are discussed.
Place, publisher, year, edition, pages
2013. Vol. 52, no 4, 1798-1806 p.
Fe-Only Hydrogenases, Active-Site Models, X-Ray Structures, Electrochemical Properties, Organometallic Complex, Hexacarbonyl Complexes, H-2 Evolution, Diiron, Ligands, Catalysis
IdentifiersURN: urn:nbn:se:kth:diva-119736DOI: 10.1021/ic301647uISI: 000315255200022ScopusID: 2-s2.0-84874023280OAI: oai:DiVA.org:kth-119736DiVA: diva2:612578
FunderSwedish Research CouncilKnut and Alice Wallenberg Foundation
QC 201303222013-03-222013-03-212013-03-22Bibliographically approved