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Photocatalytic Water Reduction and Study of the Formation of Fe I Fe 0 Species in Diiron Catalyst Sytems
Author(s) -
Li Xueqiang,
Wang Mei,
Chen Lin,
Wang Xiuna,
Dong Jingfeng,
Sun Licheng
Publication year - 2012
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201100490
Subject(s) - chemistry , photochemistry , catalysis , xanthene , photocatalysis , electron paramagnetic resonance , eosin y , electron transfer , photosensitizer , ligand (biochemistry) , hydrogenase , transfer hydrogenation , artificial photosynthesis , water splitting , hydrogen production , electron donor , ruthenium , organic chemistry , biochemistry , physics , receptor , nuclear magnetic resonance
Noble‐metal‐free systems with bio‐inspired diiron dithiolate mimics of the [FeFe]‐hydrogenase active site, namely, [(μ‐pdt)Fe 2 (CO) 5 L] [pdt=propanedithiolate; L=P(CH 2 OH) 3 ( 1 ), P(CH 3 ) 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/H 2 O) after 15 h of irradiation ( λ >450 nm) under optimal conditions. Under all of the conditions adopted, 1 that has a water soluble phosphine ligand, P(CH 2 OH) 3 displayed a higher efficiency than 2 , which bears a PMe 3 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.