TY - JOUR
T1 - Sensitizer-catalyst assemblies for water oxidation
AU - Wang, Lei
AU - Mirmohades, Mohammad
AU - Brown, Allison
AU - Duan, Lele
AU - Li, Fusheng
AU - Daniel, Quentin
AU - Lomoth, Reiner
AU - Sun, Licheng
AU - Hammarström, Leif
PY - 2015/3/16
Y1 - 2015/3/16
N2 - Two molecular assemblies with one Ru(II)-polypyridine photosensitizer covalently linked to one Ru(II)(bda)L2 catalyst (1) (bda = 2,2′-bipyridine-6,6′-dicarboxylate) and two photosensitizers covalently linked to one catalyst (2) have been prepared using a simple C-C bond as the linkage. In the presence of sodium persulfate as a sacrificial electron acceptor, both of them show high activity for catalytic water oxidation driven by visible light, with a turnover number up to 200 for 2. The linked photocatalysts show a lower initial yield for light driven oxygen evolution but a much better photostability compared to the three component system with separate sensitizer, catalyst and acceptor, leading to a much greater turnover number. Photocatalytic experiments and time-resolved spectroscopy were carried out to probe the mechanism of this catalysis. The linked catalyst in its Ru(II) state rapidly quenches the sensitizer, predominantly by energy transfer. However, a higher stability under photocatalytic condition is shown for the linked sensitizer compared to the three component system, which is attributed to kinetic stabilization by rapid photosensitizer regeneration. Strategies for employment of the sensitizer-catalyst molecules in more efficient photocatalytic systems are discussed.
AB - Two molecular assemblies with one Ru(II)-polypyridine photosensitizer covalently linked to one Ru(II)(bda)L2 catalyst (1) (bda = 2,2′-bipyridine-6,6′-dicarboxylate) and two photosensitizers covalently linked to one catalyst (2) have been prepared using a simple C-C bond as the linkage. In the presence of sodium persulfate as a sacrificial electron acceptor, both of them show high activity for catalytic water oxidation driven by visible light, with a turnover number up to 200 for 2. The linked photocatalysts show a lower initial yield for light driven oxygen evolution but a much better photostability compared to the three component system with separate sensitizer, catalyst and acceptor, leading to a much greater turnover number. Photocatalytic experiments and time-resolved spectroscopy were carried out to probe the mechanism of this catalysis. The linked catalyst in its Ru(II) state rapidly quenches the sensitizer, predominantly by energy transfer. However, a higher stability under photocatalytic condition is shown for the linked sensitizer compared to the three component system, which is attributed to kinetic stabilization by rapid photosensitizer regeneration. Strategies for employment of the sensitizer-catalyst molecules in more efficient photocatalytic systems are discussed.
UR - http://www.scopus.com/inward/record.url?scp=84925014467&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84925014467&partnerID=8YFLogxK
U2 - 10.1021/ic502915r
DO - 10.1021/ic502915r
M3 - Article
AN - SCOPUS:84925014467
VL - 54
SP - 2742
EP - 2751
JO - Inorganic Chemistry
JF - Inorganic Chemistry
SN - 0020-1669
IS - 6
ER -