Complex ruthenium polypyridyl

Nasr C, Hotchandani S, Kim WY, Schmehl RH, Kamat PV (1997) Photoelectrochemistry of composite semiconductor thin films. Photosensitization of Sn02/CdS coupled nanocrystal-Utes with a ruthenium polypyridyl complex. J Phys Chem B 101 7480-7487... 

The sensor for the measurement of high levels of CO2 in gas phase was developed, as well90. It was based on fluorescence resonance energy transfer between 0 long-lifetime ruthenium polypyridyl complex and the pH-active disazo dye Sudan III. The donor luminophore and the acceptor dye were both immobilized in a hydrophobic silica sol-gel/ethyl cellulose hybrid matrix. The sensor exhibited a fast and reversible response to carbon dioxide over a wide range of concentrations. 

With the aim of mimicking, on a basic level, the photoinduced electron-transfer process from WOC to P680+ in the reaction center of PSII, ruthenium polypyridyl complexes were used (182-187) as photosensitizers as shown in Fig. 19. These compounds are particularly suitable since their photophysical and photochemical properties are well known. For example, the reduction potential [Rum(bpy)3]3+/-[Run(bpy)3]2+ (bpy = 2,2 -bipyridine) of 1.26 V vs NHE is sufficiently positive to affect the oxidation of phenols (tyrosine). As traps for the photochemically mobilized electron, viologens or [Co(NH3)5C1]2+ were used. 

Platinized and sensitized (by ruthenium polypyridyl complexes) layered alkali-metal titanates, niobates, and titaniobates were used as photocatalysts for H2 and IJ production [91]. The use of reversed micelles as microreactors was reviewed in a feature article [92]. 

Fig. 31. Connection of 5-(3"-aminopropynyl)-2 -deoxyuridine-5 -triphosphate to the succinimide active ester arm of a ruthenium polypyridyl complex.

To illustrate the tuning aspects of the MLCT transitions in ruthenium polypyridyl complexes, let us begin by considering the well-known ruthenium mT-bipyridine complex (1). Complex 1 shows strong visible band at 466 nm, due to charge-transfer transition from metal t2g (HOMO) orbitals to tt orbitals (LUMO) of the ligand. The Ru(II)/(III) oxidation potential is at 1.3 V, and the ligand-based reduction potential is at -1.5 V versus SCE [36]. From spectro chemical and electrochemical studies of polypyridyl complexes of ruthenium, it has been con-... 

Figure 6 Tuning of HOMO (f2 ) and LUMO (tt ) orbital energy in various ruthenium polypyridyl complexes.

Figure 4.19 Examples of some typical electropolymerizable ruthenium polypyridyl complexes...

Durrant and co-workers have compared the electron injection and recombination processes of 28 or Zn-28 with that of N3 (a famous ruthenium polypyridyl complex with very high IPCE). Their experiments revealed that the electron injection and recombination kinetic for these three dyes on the surface of Ti02 are almost identical. The high IPCE for N3 dye probably originates from the electron transfer from the iodide redox couple to the dye cations. It is also possible that the lower efficiency of porphyrin sensitizers was caused by the annihilation of the excited states between the neighboring porphyrin molecules because of the closed proximity [70],... 

Both phthalocyanines and porhyrins are very promising sensitizers for wide band gap semiconductors. DSSCs fabricated from these kind of sensitizers present overall power conversion efficiency as high as 7%, which is still smaller than that achieved by the ruthenium polypyridyl complexes though, but higher than most of other dyes. The multiplicity on the molecular structure modification of these compounds provides a great potential for further promotion on their sensitization properties. The research in this field is still far from systematic and comprehensive and quantitatively much less than the researches on polypyridyl ruthenium complexes. But... 

Nasr, C. Hotchandani, S. Kamat, P. V. Photoelectrochemical behavior of composite semiconductor thin films and their sensitization with ruthenium polypyridyl complex. In Photoelectrochemistry, K. Rajeshwar, ed., The Electrochemical Society Pennington, NJ, 1997, in press. 

Photodissociation of 4-aminopyridine from ruthenium polypyridyl complex was reported recently [135], It was found that the complex does not interact with neurons, although the photoliberated ligand gives a strong physiological response. Photodissociation occurs at low-energy excitation. This research opens a new possibility for optical control of activity of selected groups of neurons for neurobio-chemical studies. 

We have applied this theoretical formulation [26-28] to a series of PCET reactions. The systems were chosen based on the availability of experimental data that had not yet been fully explained. The systems that will be discussed in this section are iron bi-imidazoline complexes, ruthenium polypyridyl complexes, amidinium-car-boxylate interfaces, DNA-acrylamide complexes, tyrosine oxidation, and the enzyme lipoxygenase. In all cases, the solvent was treated as a dielectric continuum [58, 59]. 

Figure 16.4 PCETcomproportionation reactions in ruthenium polypyridyl complexes [46].

N. lORDANOVA, S. HamMES-SchIFFER, Theoretical investigation of large kinetic isotope effects for proton-coupled electron transfer in ruthenium polypyridyl complexes, J. Am. Chem. Soc. 124, 4848-4856 (2002). 

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