Dyes as sensitizers

It has been found that certain dyes, such as methylene blue, eosin and Rose Bengal, sensitize the photo-oxidation of many organic compounds in solution [Refs. 242, 246-248, 328, 329, 371, 585, 639, 668]. More detailed investigations have shown that the photo-oxidation reaction takes place with the participation of singlet oxygen formed by the reaction between the dye excited to the triplet state and molecular oxygen. The energy of the triplet state dye molecules (Table 15) is sufficient to 

TRIPLET STATE ENERGIES OF DIFFERENT DYES [Refs. 68, 116, 133, 624] 

A dye molecule may, when excited to the triplet state, abstract a hydrogen atom from a molecule of an organic compound and form a semi-reduced radical [683] for example, 

Hydrogen peroxide may also be formed molecules of a dye [199, 368, 625] in the presence of excited 

Egerton [197, 198J found that hydrogen peroxide vapour and its radical decomposition products can degrade polymers. Also Egerton et al. [198, 199, 201] reported that many different dyes, such as acriflavin and eosin, sensitize the photochemical oxidation of textile fibres. 

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G. Lei, L. Wang, and Y. Qiu, Blue phosphorescent dye as sensitizer and emitter for white organic light-emitting diodes, Appl. Phys. Lett., 85 5403-5405 (2004). 

Dianions of Xanthene Dyes as Sensitizers of Photooxygenation Reactions... 

Comparative Effects of Various Dyes as Sensitizers on Nucleic Acids... 

The reactions which will be discussed here are basic in the application of dyes as sensitizer for photographic materials like silver halides, zinc oxide and others. Model experiments can be performed at electrodes of such materials which help to understand the mechanism of spectral sensitization in photography. 

New sources of singlet oxygen continue to be developed. Near i.r. radiation ( > 900 nm), in the presence of a cyanine dye as sensitizer, has been used to generate 102.100 Thermal decomposition of the ozonide (52) produces 102 and the... 

There is strong interest in the photodynamic therapy of cancer using porphyrins and other biodegradable dyes as sensitizers for DNA photolysis. Some evidence exists that porphyrins inhibit HTV-1, the virus responsible for AIDS. Occasional medical applications and biological effects of DNA-porphyrin interactions result from sensitized photochemical DNA cleavage reactions. The ell-piticine substituted porphyrin (Scheme 8.6.2) may, for example, be useful. The... 

In other studies of a broader scope, Loutfy and Law (15,16) reported on the spectroscopy of fluorescence probes in polymeric matrices and on their intramolecular charge-transfer (ICT) interactions. Law (17) also proposed application of the viscosity-dependent fluorescence dyes as sensitive probes for measuring polarity, microviscosity, and structural changes in a micro- environment. More recently, Loutfy and Teegarden (18) have exploited the unique properties of julolidinemalononitr ile (a "molecular rotor" probe with viscosity-dependent fluorescence) for determination of polymer chain tacticity. 

Polypyridyl Ru Complexes and Organic Dyes as Sensitizers The preparation... 

Fig. S Schematic energy band diagram of suitable and unsuitable metal oxides for organic dyes as sensitizers. Election injection from the dye-excited state to the energy level of conduction band (CB) is energetically favorable for wide bandgap oxides such as TIO2 and ZnO [261, 264], but forbidden for large bandgap oxides such as ZrOz [461].

Some features of the laser photo-CIDNP method will now be summarized. We have shown that hy employing a dye as sensitizer nuclear spin polarization can be generated in native proteins. When flavins are used as dyes nmr lines of Tyr, His, and Trp residues can be selectively enhanced when these residues are accessible to the photo-excited dye. Thus, the method constitutes a "surface probe" with the very high resolution of the nmr technique, which is capable of resolving lines due to individual residues. Large enhancements, often of the order of a magnitude or more, are translated in considerable time savings. 

M. Rani, Saeed J. Abbas, S.K. Tripathi, Influence of annealing temperature and organic dyes as sensitizers on sol-gel derived Ti02 films. Mater. Sci. Eng. B, 187 (2014) 75-82. 

Kabatc, J. Multicationic monomethine dyes as sensitizers in two- and three-component photoinitiating systems for multiacrylate monomers. J. Photochem. PhotobioL, A Chem. 2010, 214, 74-85. 

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