Reductive Behavior of [Fe₂(CO)₄(κ²‐dmpe){μ‐(SCH₂)₂NBn}]: Effect of Symmetrization on the Rotated Conformation in Fe^I‐Fe^I Models of [2Fe]_H Subsite of [Fe‐Fe]­H₂ases

Abstract

The reduction of the compound [Fe2(CO)4(κ2‐dmpe){μ‐(SCH2)2NBn}] [dmpe = 1,2‐bis(dimethylphosphino)ethane], which is considered as an FeI‐FeI model of the [2Fe]H subsite of [Fe‐Fe]H2ases with a rotated conformation in the solid state, was investigated by cyclic voltammetry. Under reductive conditions, [Fe2(CO)4(κ2‐dmpe){μ‐(SCH2)2NBn}] undergoes electron‐transfer‐catalyzed isomerization to afford an isomer featuring a bridging diphosphine [Fe2(CO)4(μ‐dmpe){μ‐(SCH2)2NBn}]. Comparison of the crystallographic structures of the two isomers affords unique and direct experimental evidence that dissymmetrical coordination of the chelate ligand is required to promote the rotated conformation at one iron atom in this compound. DFT calculations were performed to rationalize this isomerization process and the slightly distorted structure of [Fe2(CO)4(μ‐dmpe){μ‐(SCH2)2NBn}]. The symmetrization of the coordination sphere results in the disruption of the agostic interaction that stabilized the rotated isomer.

Electrochemical and Theoretical Investigations of the Oxidatively Induced Reactivity of the Complex [Fe2(CO)4(κ2‐dmpe)(μ‐adtBn)] Related to the Active Site of [FeFe] Hydrogenases

“…Solvents were deoxygenated and dried according to standard procedures. [Fe 2 (CO) 4 (κ 2 ‐dmpe)(μ‐adt Bn )] ( 1 ) was prepared according to the reported procedure . The NMR spectra ( 1 H, 31 P) were recorded at room temperature in deuterated solvents with a Bruker AMX 400 or AC300 spectrometer of the “ Service RMN‐SM de l′Université de Bretagne Occidentale ”.…”

“…[Fe 2 (CO) 4 (k 2 -dmpe)(m-adt Bn )] (1)w as prepared according to the reported procedure. [19,35] The NMR spectra ( 1 H, 31 P) were recorded at room temperature in deuterated solvents with aB ruker AMX 400 or AC300 spectrometer of the "Service RMN-SM de l'UniversitØ de Bretagne Occidentale". They were referenced to SiMe 4 ( 1 H) or H 3 PO 4 ( 31 P).…”

Direct ab‐initio molecular dynamics study on the radiation effects on catalytic triad composed of Ser‐His‐Glu residues

“…Many experimental and theoretical works on the DNA damage have been carried out in the last decade . On the other hand, the studying of radiation enzyme damages is limited . Acetylcholinesterase (AChE) is one of the enzymes which is composed of catalytic triad in the active site consisting of the amino acids, serine (Ser), histidine (His), and glutamic acid (Glu) .…”

“…High energy irradiation to the hydrogen bonded system is important in relevance with the initial process of DNA damages [1][2][3] and enzyme damages. [4][5][6][7] If DNA base pair is ionized by the irradiation, a proton is transferred into the neighbored base along the hydrogen bond, while a defect is formed in the damaged DNA. [8,9] The defect leads to replication and transcriptional errors in DNA.…”

“…[1][2][3]8,9] On the other hand, the studying of radiation enzyme damages is limited. [4][5][6][7] Acetylcholinesterase (AChE) is one of the enzymes which is composed of catalytic triad in the active site consisting of the amino acids, serine (Ser), histidine (His), and glutamic acid (Glu). [10][11][12] AChE can synthesize neurotransmitter acetylcholine (ACh) by the transition of acetyl groups of acetyl CoA.…”