title: Ligand effects on the electrochemical behavior of [Fe2(CO)5(L){μ-(SCH2)2(Ph)P=O}] (L = PPh3, P(OEt)3) hydrogenase model complexes.
abstract: In this paper we study the influence of substituting one CO ligand in [Fe2(CO)6{μ-(SCH2)2(Ph)P=O}] (1) by better σ-donor L ligands affording [Fe2(CO)5(L){μ-(SCH2)2(Ph)P=O}] {L = PPh3 (2) and P(OEt)3 (3)} in relation to the steric interactions and the voltammetric behavior. Cyclic voltammetric investigations under N2 and CO showed remarkable differences in the electrochemical behaviour of complexes 2 and 3: (i) Complex 2 tends to expel PPh3 upon reduction whereas complex 3 exhibits chemical reversibility and (ii) Under CO, complex 3 reacts with CO affording a new compound P, which shows a reversible wave at E1/2 ∼ -0.9 V (vs. ferrocenium/ferrocene couple). The presence of CO assists the formation of 1 after electrochemically induced loss of PPh3 during the voltammetric experiment of 2. Using DFT calculations we provide an explanation for the difference in stabilities between the Fe-PPh3 and Fe-P(OEt)3 bonds.
authors: Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität Jena, Humboldtstrasse 8, D-07743 Jena, Germany. wolfgang.weigand@uni-jena.de.
authors: Laith R
authors: LR
authors: Almazahreh
authors: Wolfgang
authors: W
authors: Imhof
authors: Jean
authors: J
authors: Talarmin
authors: Philippe
authors: P
authors: Schollhammer
authors: Helmar
authors: H
authors: Görls
authors: Mohammad
authors: M
authors: El-khateeb
authors: Wolfgang
authors: W
authors: Weigand
mesh_terms: D002248:Carbon Monoxide / Q000737:chemistry; D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry*; D018360:Crystallography, X-Ray; D055664:Electrochemical Techniques; D005290:Ferric Compounds / Q000737:chemistry*; D006864:Hydrogenase / Q000737:chemistry / Q000378:metabolism; D007506:Iron-Sulfur Proteins / Q000737:chemistry / Q000378:metabolism; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D013237:Stereoisomerism
chemical_list: D056831:Coordination Complexes; D005290:Ferric Compounds; D007506:Iron-Sulfur Proteins; D008024:Ligands; D002248:Carbon Monoxide; C118830:iron hydrogenase; D006864:Hydrogenase