title: Oxidatively induced reactivity of [Fe2(CO)4(κ2-dppe)(μ-pdt)]: an electrochemical and theoretical study of the structure change and ligand binding processes.
abstract: The one-electron oxidation of the diiron complex [Fe(2)(CO)(4)(κ(2)-dppe)(μ-pdt)] (1) (dppe = Ph(2)PCH(2)CH(2)PPh(2); pdt = S(CH(2))(3)S) has been investigated in the absence and in the presence of P(OMe)(3), by both electrochemical and theoretical methods, to shed light on the mechanism and the location of the oxidatively induced structure change. While cyclic voltammetric experiments did not allow to discriminate between a two-step (EC) and a concerted, quasi-reversible (QR) process, density functional theory (DFT) calculations favor the first option. When P(OMe)(3) is present, the one-electron oxidation produces singly and doubly substituted cations, [Fe(2)(CO)(4-n){P(OMe)(3)}(n)(κ(2)-dppe)(μ-pdt)](+) (n = 1: 2(+); n = 2: 3(+)) following mechanisms that were investigated in detail by DFT. Although the most stable isomer of 1(+) and 2(+) (and 3(+)) show a rotated Fe(dppe) center, binding of P(OMe)(3) occurs at the neighboring iron center of both 1(+) and 2(+). The neutral compound 3 was obtained by controlled-potential reduction of the corresponding cation, while 2 was quantitatively produced by reaction of 3 with CO. The CO dependent conversion of 3 into 2 as well as the 2(+) ↔ 3(+) interconversion were examined by DFT.
authors: UMR CNRS 6521, Chimie, Electrochimie Moléculaires et Chimie Analytique, Université de Bretagne Occidentale, UFR Sciences et Techniques, Cs 93837, 29238 Brest-Cedex 3, France.
authors: Dounia
authors: D
authors: Chouffai
authors: Giuseppe
authors: G
authors: Zampella
authors: Jean-François
authors: JF
authors: Capon
authors: Luca
authors: L
authors: De Gioia
authors: Frédéric
authors: F
authors: Gloaguen
authors: François Y
authors: FY
authors: Pétillon
authors: Philippe
authors: P
authors: Schollhammer
authors: Jean
authors: J
authors: Talarmin
mesh_terms: D000838:Anions; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D032701:Biomimetics; D002248:Carbon Monoxide; D002384:Catalysis; D002412:Cations; D018360:Crystallography, X-Ray; D004563:Electrochemistry; D006864:Hydrogenase / Q000737:chemistry* / Q000378:metabolism; D007501:Iron / Q000737:chemistry* / Q000378:metabolism; D007506:Iron-Sulfur Proteins / Q000737:chemistry* / Q000378:metabolism; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008962:Models, Theoretical; D015394:Molecular Structure; D010084:Oxidation-Reduction; D011789:Quantum Theory; D013816:Thermodynamics
chemical_list: D000838:Anions; D001426:Bacterial Proteins; D002412:Cations; D007506:Iron-Sulfur Proteins; D008024:Ligands; D002248:Carbon Monoxide; D007501:Iron; D006864:Hydrogenase