Ruthenium trisbipyridyl

Another example of a photoredox molecular switch is based on a ferrocene-ruthenium trisbipyridyl conjugate, in which the luminescent form 4 switches to the non-luminescent form 5 upon electrochemical oxidation (Figure 2/bottom)171. Biological systems exploit the interplay of redox and molecular recognition to regulate a wide variety of processes and transformations. In an attempt to mimic such redox systems, Deans et al. have reported a three-component, two-pole molecular switch, in which noncovalent molecular recognition can be controlled electrochemically. x Willner et al. have reported on their research activities in developing novel means to achieve reversible photostimulation of the activities of biomaterials (see Chapter 6).[91 Recently, we have shown that it is possible to switch the luminescence in benzodi-furan quinone 6 electrochemically. 101 The reduction in THF of the quinone moiety... 

The triad multistep electron transfer strategy is, of course, not limited to tetrapyrroles. For example, Meyer and coworkers have reported triad 19 [Ru(Me(bpy)-3DQ2+)(Me(bpy)-PTZ)2]4+, which is based upon a ruthenium trisbipyridyl chromophore [70, 71]. The Mebpy-PTZ and Mebpy-3DQ2+ ligands are shown as structures 20 and 21, respectively. This triad was again evidently... 

Nakahira, T. Graetzel, M. Visible light sensitization of platinized T102 photocatalyst by surface-adsorbed poly(4-vinylpyridine) derivatized with ruthenium trisbipyridyl complex, Makromol. Chem., Rapid Commun. 1985, 6, 341. 

Figure 14. Kb values, from intervalence measurements, on a log scale, as a function of the through-space metal-metal distance +, ruthenium bipyridylpolyene complexes (series 1) , ruthenium bis(terpyridyl) complexes (series 2) , ruthenium bis(cyclometallated) complexes, dipyridylbenzene family (series 3) , ruthenium bis(cyclometallated) complexes, phenylpyridine family (series 4) A, bis(ferrocenyl)polyenes (series 5). Additional measurements a, bis(cyclometallated) complexes, phenylpyridine family with diethynylanthracene as spacer b, bis(ferrocene) with three phenylene and four vinylene units as spacer c, bis[ruthenium(trisbipyridyl)] with five double bonds as spacer. Note that the Cp (dppe)Fe system bridged by octatetrayne (13 A, 0.32 eV) is outside the graph.

The hypothesis that the high yields obtained in the bifunctional catalytic system is caused by adsorption of the sensitizer on the surface of the colloidal Ti02 particle lead to the discovery of relay free water decomposition systems350. The only components present in solution are a sensitizer and the catalyst. The sensitizers employed331 were ruthenium trisbipyridyl complexes of the structure ... 

Immunoassays presently form probably the most active area of exploitation of CL, ECL and BL, as evidenced by the extensive commerciahzation of luminescent immunoassay analyzers and test kits. Among these, acridinium ester-based CL assays for alkaline phosphatase and amplified CL assays using peroxidase labels have become the most widespread [207, 208]. Besides immunosassays CL and BL have been used in nucleic acid assays [209-211] and in cellular studies concerning, for instance, phagocytosis [212]. ECL immunoassays based on ruthenium trisbipyridyl labels are now becoming popular in clinical immunoassay analyzers [213]. 

Figure 2.16 Structure of the octahedral ruthenium (II) trisbipyridyl complex. The orange colour of this complex results from metal-to-ligand charge-transfer (MLCT) transitions...

The attachment of bipyridine moieties also enables the synthesis of homo- and heteroleptic ruthenium(II)trisbipyridyl complexes with interesting photochemical properties [56]. 

A homogeneous, bimolecular photoredox system, which has been extensively investigated, involves ruthenium(II) trisbipyridyl [Ru(bpy)2 + ] as photocatalyst and methylviologen (MV2+) as electron acceptor, where triethanolamine (TEOA) or ethylenediamintetraacetate (EDTA) are used as sacrificial electron donors for the reduction of Ru(bpy)2 + (Tazuke et al, 1987) ... 

Le Goff A, Cosnier S (2011) Photocurrent generation by MWCNTs functionalized with bis-cyciometaiiated Ir(III)- and trisbipyridyl ruthenium (II)- polypyrrole films. J Mater Chem 21 3910-3915. doi 10.1039/C0JM03472J... 

Fibrinogen has been rapidly photo-cross-Unked in the presence of ruthenium as the trisbipyridyl complex and the oxidant ammonium or sodium persulfate by light to yield high-molecular-weight products that have strong in vitro adhesive properties [73]. A mixture of fibrinogen (150 mg/mL), 2 mM Ru (bpy)3Cl2, and 20 mM sodium persulfate was prepared, and applied immediately to wounds, followed by... 

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