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| 2. |
- Yang, Yong, et al.
(författare)
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Nickel Complex with Internal Bases as Efficient Molecular Catalyst for Photochemical H-2 Production
- 2014
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Ingår i: ChemSusChem. - : Wiley. - 1864-5631 .- 1864-564X. ; 7:10, s. 2889-2897
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Tidskriftsartikel (refereegranskat)abstract
- A Ni complex with internal bases that contain bipyridine-derived ligands, [Ni(L)(2)(H2O)(2)](BF4)(2) ([1](BF4)(2), L=2-(2-pyridyl)-1,8-naphthyridine), and a reference complex that bears analogous bipyridine-derived ligands but without an internal base, [Ni(L)(3)](BF4)(2) ([2](BF4)(2), L=2-(2-pyridyl)quinoline), were synthesized and characterized. The electrochemical properties of these complexes were studied in CH3CN, H2O, and a mixture of EtOH/H2O. The fluorescence spectroscopic studies suggest that both dynamic and the sphere-of-action static quenching exist in the fluorescein Fl(2-)/[1](2+) and Fl(2-)/[2](2+) systems. These noble-metal-free molecular systems were studied for photocatalytic H-2 generation. Under optimal conditions, the turnover number of H-2 evolution reaches 3230 based on [1](2+), whereas [2](2+) displays only approximately one third of the turnover of [1](2+). A plausible mechanism for the catalytic H-2 generation by [1](2+) is presented based on DFT calculations.
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| 3. |
- Li, Xueqiang, et al.
(författare)
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Photocatalytic Water Reduction and Study of the Formation of FeIFe0 Species in Diiron Catalyst Sytems
- 2012
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Ingår i: ChemSusChem. - : Wiley. - 1864-5631. ; 5:5, s. 913-919
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Tidskriftsartikel (refereegranskat)abstract
- Noble-metal-free systems with bio-inspired diiron dithiolate mimics of the [FeFe]-hydrogenase active site, namely, [(mu-pdt)Fe2(CO)5L] [pdt=propanedithiolate; L=P(CH2OH)3 (1), P(CH3)3 (2)], as water reduction catalysts with xanthene dyes as photosensitizers and triethylamine as a sacrificial electron donor were studied for visible-light-driven water reduction to hydrogen. These systems display good catalytic activities with the efficiencies in hydrogen evolution of up to 226 turnovers for 1, if Eosin Y was used as the photosensitizer in an environmentally benign solvent (EtOH/H2O) after 15 h of irradiation (?>450 nm) under optimal conditions. Under all of the conditions adopted, 1 that has a water soluble phosphine ligand, P(CH2OH)3 displayed a higher efficiency than 2, which bears a PMe3 ligand. The photoinduced electron transfer in the systems was studied using fluorescence, transient absorption, time-resolved UV/Vis, and in situ electron paramagnetic resonance (EPR) spectroscopy. A new electron-transfer mechanism is proposed for hydrogen evolution by these iron-based photocatalytic systems.
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