Improving the Photosensitizing Properties of Ruthenium Polypyridyl Complexes Using 4-Methyl-2,2鈥?bipyridine-4鈥?carbonitrile as an Auxiliary Ligand

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• 作者：Juan H. Mecchia Ortiz ; Nadia Vega ; David Comedi ; M贸nica Tirado ; Isabel Romero ; Xavier Fontrodona ; Teodor Parella ; F. Eduardo Mor谩n Vieyra ; Claudio D. Borsarelli ; N茅stor E. Katz
• 刊名：Inorganic Chemistry
• 出版年：2013
• 出版时间：May 6, 2013
• 年：2013
• 卷：52
• 期：9
• 页码：4950-4962
• 全文大小：699K
• 年卷期：v.52,no.9(May 6, 2013)
• ISSN：1520-510X

文摘

We report in this work the synthesis and spectroscopic, electrochemical, spectroelectrochemical, and photophysical characterization of a novel series of ruthenium polypyridyl complexes with 4-methyl-2,2鈥?bipyridine-4鈥?carbonitrile (Mebpy-CN) as an auxiliary ligand of general formula [Ru(bpy)_3鈥?i>x(Mebpy-CN)_x](PF₆)₂ (x = 1鈥?) (with bpy = 2,2鈥?bipyridine). A significant increase in the lifetime and quantum yield of emission of the lowest ³MLCT excited state is disclosed when going from x = 1 to x = 3, evidencing an improvement of the photosensitizing properties with respect to [Ru(bpy)₃](PF₆)₂. Furthermore, quenching by molecular oxygen of ³MLCT excited states of the three complexes produced singlet molecular oxygen (¹O₂) with quantum yield values higher than that of [Ru(bpy)₃]²⁺ in CH₃CN. The structure of the complex with x = 1 has been determined by X-ray diffraction. The photoconductivity of ZnO nanowires covered with this same complex is increased by an order of magnitude, pointing to its feasibility as a component of a DSSC. A new dinuclear complex with Mebpy-CN as a bridging ligand has also been prepared and characterized by physicochemical techniques. The derived mixed-valent species of formula [(bpy)₂Ru^II(Mebpy-CN)Ru^III(NH₃)₅]⁵⁺ displays a considerable metal鈥搈etal electronic coupling due to the delocalization effect of a nitrile group in the 4鈥?position of the bpy ring.