Zhiyin Xiao

Diiron hexacarbonyl complexes bearing naphthalene-1,8-dithiolate bridge moiety as mimics of the sub-unit of [FeFe]-hydrogenase: synthesis, characterisation and electrochemical investigations

Eight diiron hexacarbonyl complexes bearing a 1,8-dithionaphthalenyl bridging linkage as mimics of the diiron subunit of [FeFe]-hydrogenase are reported. Reaction of Fe3(CO)12 with naphtha[1,8-cd][1,2]dithiole-n-carbaldehyde (n = 2: 2a or 4: 2b) gave two complexes, [Fe2(μ-S)2R(CO)6] (–SRS– = n-formylnaphthalene-1,8-bis(thiolate), n = 2: 3a, 4: 3b), which were further used as precursors to prepare six other complexes by manipulating the formyl groups. Converting the corresponding formyl group into a hydroxymethyl group (CH2OH) led to complexes 4a and 4b. Their reactions with halobutanoyl chloride formed complexes 5a and 5b (halo group = Cl), and 6a and 6b (halo group = Br), respectively. Among the complexes, 3a, 3b, 4b, 5b, and 6a were crystallographically analysed. Electrochemical investigations into these complexes revealed that the formyl group exerts profound electronic influence on the electrochemistry, and thus catalysis of proton reduction, due to its involvement in the conjugation of the bridging linkage. DFT calculations indicate that the formyl group influences the electrochemistry and catalysis by significantly altering the composition of the LUMOs.

Photoinduced Carbon Monoxide Release from Half‐Sandwich Iron(II) Carbonyl Complexes by Visible Irradiation: Kinetic Analysis and Mechanistic Investigation

Three half-sandwich iron(II) complexes, [Fe(η(5) -Cp)(cis-CO)2 X] (X(-) =Cl(-) , Br(-) , I(-) ), were synthesized and characterized. The kinetics of the CO-releasing behaviour of these complexes upon illumination by visible irradiation in various media was investigated. Our results indicated that the CO release was significantly affected by the auxiliary ligands. Of the three light sources used (blue, green, and red), blue light exhibited the highest efficiency. In the photoinduced CO release, the solvents and exogenous nucleophiles in the media were involved, which allowed their CO-releasing reaction to comply with pseudo first-order model rather than the characteristic zero-order model for a photochemical reaction. In aqueous media (D2 O), an intermediate bearing the core of {Fe(II) (cis-CO)2 } involving cleavage of cyclopentadiene was detected. Despite the non-absorption of the red light, its illumination combined with nucleophilic substitution did cause considerable CO release. Assessment of the cytotoxicity of the three complexes indicated that they showed good biocompatibility.

Enable PVC plastic for a novel role: its functionalisation with diiron models of the sub-unit of [FeFe]–hydrogenase, assembly of film electrodes, and electrochemical investigations

Three polymers functionalised with diiron carbonyl units, PVC–Fe-A, -B, and -C, were prepared using commercially available polymer PVC (polyvinyl chloride). PVC–Fe-A resulted from the reaction of the reduced form of a diiron complex, [Fe2(μ-S)2(CO)6], with PVC, whereas PVC–Fe-B and PVC–Fe-C were, respectively, prepared by reacting PVC–N3, the polymer functionalised with azide groups by substitution of the chloride of the polymer, with two diiron complexes, [Fe2(μ-SCH2CCH)2(CO)6] (1) and [Fe2(μ-SnBut)(μ-SCH2CCH)(CO)6] (2, nBut = –CH2CH2CH2CH3), via “click chemistry” under the catalysis of CuI. Those polymers were characterised using infrared spectroscopy (IR), scanning electron microscopy (SEM), and thermal gravimetric analysis (TGA). Film electrodes were assembled using a spin-coating technique by casting a mixture of the functionalised polymer, MWCNTs (multi-wall carbon nanotubes), and Nafion onto the surface of a vitreous carbon electrode. The assembled electrodes exhibited electrochemical responses and catalysis on proton reduction in a medium of acetonitrile-acetic acid with a positive shift in reduction potential by over 400 mV compared to the precursor diiron complexes (1 and 2).

[FeFe]-hydrogenase-inspired membrane electrode and its catalytic evolution of hydrogen in water

A membrane electrode assembled with electrospun-fibers derived from a composite of cellulose acetate (CA) functionalised with carboxylated multiwall carbon nanotubes (cMWCNTs), polyvinyl pyrrolidone (PVP), and diiron model ([Fe2(edt)(CO)6], edt = ethanedithiolate) catalyses proton reduction in water with the presence of acetic acid.

Reaction of three cyclic thioester ligands with triiron dodecacarbonyl and possible reaction mechanisms

AbstractThree cyclic thioesters of the formula “

Influence of the basicity of internal bases in diiron model complexes on hydrides formation and their transformation into protonated diiron hexacarbonyl form

-\hbox {SCH}_{2}\hbox {CH}_{2}\hbox {SCO}(\hbox {CH}_{2})_{\mathrm{n}}-

A rare bond between a soft metal (FeI) and a relatively hard base (RO−, R = phenolic moiety)

-SCH2CH2SCO(CH2)n-” (