Xu-Feng Liu

Synthesis and characterization of diiron ethanedithiolate complexes with monosubstituted phosphine ligands

Abstract Reactions of (μ-edt)Fe2(CO)6 (edt = SCH2CH2S) (1) with the monophosphine ligands Ph2PCH2Ph, Ph2PC6H11, Ph2PCH2CH2CH3, or P(2-C4H3O)3 in the presence of Me3NO∙2H2O afforded (μ-edt)Fe2(CO)5L [L = Ph2PCH2Ph, 2; Ph2PC6H11, 3; Ph2PCH2CH2CH3, 4; P(2-C4H3O)3, 5] in 70–88% yields. Complexes 2–5 were characterized by spectroscopy and single crystal X-ray diffraction analysis. The phosphorus of 2–5 is in an apical position of the distorted octahedral geometry of iron.

Structural studies of diiron complexes with monophosphine ligands tris(4-chlorophenyl)phosphine or diphenyl-2-pyridylphosphine

Abstract Four diiron dithiolate complexes with monophosphine ligands have been prepared and structurally characterized. Reactions of (μ-SCH2CH2S-μ)Fe2(CO)6 or [μ-SCH(CH3)CH(CH3)S-μ]Fe2(CO)6 with tris(4-chlorophenyl)phosphine or diphenyl-2-pyridylphosphine in the presence of Me3NO·2H2O afforded diiron pentacarbonyl complexes with monophosphine ligands (μ-SCH2CH2S-μ)Fe2(CO)5[P(4-C6H4Cl)3] (1), (μ-SCH2CH2S-μ)Fe2(CO)5[Ph2P(2-C5H4N)] (2), [μ-SCH(CH3)CH(CH3)S-μ]Fe2(CO)5[P(4-C6H4Cl)3] (3), and [μ-SCH(CH3)CH(CH3)S-μ]Fe2(CO)5[Ph2P(2-C5H4N)] (4) in good yields. Complexes 1–4 were characterized by elemental analysis, 1H NMR, 31P{1H} NMR and 13C{1H} NMR spectroscopy. Furthermore, the molecular structures of 1–4 were confirmed by X-ray crystallography.

Synthesis and characterization of diiron(I) 1,2-dimethylethanedithiolate complexes with bridging or chelating 1,2-bis(diphenylphosphino)ethylene

Abstract The reaction of complex [μ-SCH(CH3)CH(CH3)S-μ]Fe2(CO)6 (1) with trans-1,2-bis(diphenylphosphino)ethylene (trans-dppv) in the presence of Me3NO∙2H2O in CH2Cl2/CH3CN afforded complex {[μ-SCH(CH3)CH(CH3)S-μ]Fe2(CO)5}2(trans-dppv) (2) with a bridging dppv. Complex [μ-SCH(CH3)CH(CH3)S-μ]Fe2(CO)4(cis-dppv) (3) was prepared by the reaction of 1 with cis-dppv and Me3NO∙2H2O. The new complexes 2 and 3 were characterized by elemental analysis, spectroscopy, and X-ray diffraction analysis.

The effect of a pendant amine in phosphine ligand on the structure and electrochemical property of diiron dithiolate complexes

Abstract In order to explore the effect of a pendant amine on a phosphine ligand on the structure and electrochemical properties of diiron dithiolate complexes, this work reports the crystallographic and electrocatalytic comparisons of three diiron monophosphine complexes Fe2(μ-pdt)(CO)5{Ph2P(NHR)} [pdtu2009=u2009propanedithiolate (SCH2CH2CH2S); Ru2009=u2009para-methoxycarbonylphenyl (C6H4CO2Me-p) (1), para-methoxyphenyl (C6H4OMe-p) (2) and phenyl (Ph) (3)] with a pendant amine and one reference analogue Fe2(μ-pdt)(CO)5{Ph2P(CH2Ph)} (4). While the new complex 4 has been characterized by elemental analysis and various spectroscopic techniques, the molecular structures of 3 and 4 were further determined by X-ray crystallography. In addition, the electrochemical properties of 1–4 were studied in acetonitrile (MeCN) in the absence and presence of acetic acid (HOAc) as a mild proton source using cyclic voltammetry (CV). This may demonstrate that they are found to be active electrocatalysts for proton reduction to hydrogen (H2).

Carbonyl substitution of the dicobalt-iron complex (μ3-S)FeCo2(CO)9 with monophosphane or diphosphane ligands

Abstract Eight new dicobalt-iron clusters have been synthesised and structurally characterized. Treatment of (μ3-S)FeCo2(CO)9 (A) with monophosphane ligands tris(4-fluorophenyl)phosphane, tris(4-methoxyphenyl)phosphane, or tris(2-furyl)phosphane in the presence of Me3NO∙2H2O afforded monosubstituted complexes (μ3-S)FeCo2(CO)8L [L = P(4-C6H4F)3, 1; P(4-C6H4OMe)3, 3; P(2-C4H3O)3, 5] and disubstituted complexes (μ3-S)FeCo2(CO)7L2 [L = P(4-C6H4F)3, 2; P(4-C6H4OMe)3, 4; P(2-C4H3O)3, 6]. Reaction of complex A with Ph2PN[CH(CH3)2]PPh2 in refluxing toluene gave complex (μ3-S)FeCo2(CO)7{Ph2PN[CH(CH3)2]PPh2} (7) with an intramolecular bridging diphosphane ligand. Reaction of complex A with trans-1,2-bis(diphenylphosphino)ethylene (trans-dppv) and Me3NO∙2H2O yielded complex [(μ3-S)FeCo2(CO)8]2(trans-Ph2PCH = CHPPh2) (8) with an intermolecular bridging diphosphane ligand. The new complexes 1–8 were characterized by elemental analysis, IR, 1H NMR, 31P{1H} NMR, and 13C{1H} NMR spectroscopy, particularly for 1, 3, and 6–8 by X-ray crystallography.