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A Ru‐Hbpp‐Based Water‐Oxidation Catalyst Anchored on Rutile TiO 2
Author(s) -
Francàs Laia,
Sala Xavier,
BenetBuchholz Jordi,
Escriche Lluís,
Llobet Antoni
Publication year - 2009
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.200800191
Subject(s) - ruthenium , chemistry , catalysis , ligand (biochemistry) , terpyridine , rutile , pyrazole , polymer chemistry , medicinal chemistry , inorganic chemistry , organic chemistry , metal , biochemistry , receptor
In support of a split : A water oxidation catalyst based on ruthenium bis‐(2‐pyridyl)pyrazole anchored on rutile TiO 2 was prepared. The performance of this new material with regard to its capacity to catalytically oxidize water to molecular oxygen in a heterogeneous phase was evaluated.Two organic ligands based on bis‐(2‐pyridyl)pyrazole (Hbpp) functionalized with a para ‐methylenebenzoic acid (Hbpp‐R a ) or its ester derivative (Hbpp‐R e ) were prepared and characterized. The ester‐functionalized ligand was then used to prepare a series of related dinuclear ruthenium complexes of general formula [Ru II 2 ( L‐ L)(bpp‐R n )(trpy) 2 ] m + (L‐L=μ‐Cl, μ‐acetato, or (H 2 O) 2 ; n =e or a; trpy=2,2′:6′,2′′‐terpyridine; m =2 or 3). The complexes were characterized in solution by 1D and 2D NMR spectroscopy, UV/Vis spectroscopy, and electrochemical techniques. The [Ru II 2 (μ‐Cl)(bpp‐R e )(trpy) 2 ](PF 6 ) 2 complex was further characterized in the solid state by X‐ray diffraction. The complexes containing the free carboxylic acid ligand were anchored onto rutile TiO 2 and treated with 0.1 M triflic acid solution to generate the homologous water‐oxidation catalysts TiO 2 ‐[Ru II 2 (H 2 O) 2 (bpp‐R a )(trpy) 2 ] 2+ . This new hybrid material catalytically oxidizes water to molecular oxygen in a heterogeneous manner using Ce IV as chemical oxidant. The generation of molecular oxygen is accompanied by the formation of carbon dioxide as well as some leaching of the Ru catalyst.