Photosensitizers artificial

J. Anzai and T. Osa, Photosensitive artificial membranes based on azobenzene and spirobenzo-pyran derivatives, Tetrahedron 50, 4039 4070 (1994). 

In another field of current activity, the aggregation behavior of amphiphile molecules is modified and controlled by photoswitching of azobenzenes that are covalently linked as a component of some part or all the amphiphilic molecules. Japanese workers collected a large amount of data on photosensitive artificial membranes based on azobenzene derivatives. ... 

Avoid exposure to sunlight and artificial light because this may cause a photosensitivity reaction... 

The water-soluble compound 2-amino[l,8]naphthyridine is a novel DNA-binding photosensitizer, which may be employed for the one-electron oxidation of DNA. It is also reported to be an excellent chromophore for the design of artificial electron-accepting nucleobases <1999TL6029>. 

Photochemical conversion of solar energy in artificial systems (as in natural photosynthesis) is essentially based on electron-transfer between an excited photosensitizer (A ) and an appropriate electron acceptor (B)... 

Recently, the DSSC has been used for an educational demonstration of solar energy-to-electricity conversion system because of its simple fabrication [12,168]. Students could purchase DSSC kits including all components such as TCO-coated glass, 2 electrodes, blackberries (i.e., dye), and electrolyte solution [169,170] and easily demonstrate an artificial photosynthetic process. For detailed studies, it is possible to purchase raw materials, including Ru dye photosensitizers, Ti02 paste, and sealing materials, from Solaronix S. A. [171]. 

The mixed calcium salt is dissolved in ZN nitric acid, using 15ml of the latte for every 2g of the material The clear solution is diluted to double its volume with distilled water and fig of silver nitrate (for each 2g portion of calcium salt) is dissolved in the liquid. The mixture is stirred until the beige precipitate settles out. This is filtered, the silver hypophosphate rinsed with acetone, and the product is dried in warm air. It is only slighter photosensitive and may be stored in clear bottles in artificial light for extended periods of time. 

The fat-soluble vitamins are photosensitive, and therefore all operations with vitamin solutions and vitamin-containing materials should be carried out in subdued light or in low-actinic amber glassware. Ideally, the laboratory or a dedicated room within the laboratory should have the windows (if any) covered with effective blinds, and artificial lighting should be provided by F40GO gold (or equivalent) fluorescent lamps, which exclude radiation wavelengths of less than 500 nm. 

Different aspects involved in the design of artificial photosynthetic systems have been discussed. Charged colloids and water-oil microemulsions provide effective organized media for controlling photosensitized electron transfer processes. Development of catalysts capable of utilizing the photoproducts in chemical routes, particularly in multi-electron fixation processes is of major... 

Fig. 7. General scheme of an artificial photosynthetic device S — photosensitizer, A — electron acceptor, D — electron donor, and P2 — reactants (substrates) for the reduction and oxidation processes, respectively...

Fig. 16a, b. Examination of reduction and oxidation processes of artificial photosynthetic devices by means of sacrificial components a) application of sacrificial electron donor in a photosensitized reduction process b) application of a sacrificial electron acceptor in a photosensitized oxidation process... 

Photosensitized regeneration of an oxidized cofactor, i.e. NAD(P)+ or a reduced cofactor NAD(P)H, could provide general routes for oxidative or reductive biocatalyzed photosynthetic transformations (see Sect. 3.2.3). Coupling of the regenerated NAD(P)+/NAD(P)H cofactors to enzymes that depend on these cofactors, opens a broad array of feasible photo-biocatalytic syntheses. An alternative approach to couple enzymes as catalysts for artificial photosynthetic... 

Kay, A. Graetzel, M. Artificial photosynthesis. 1. Photosensitization of Ti02 solar cells with chlorophyll derivatives and related natural porphyrins, J. Phys. Chem. 1993, 97, 6272. 

For H202 photoproduction by artificial model systems, 0.1 mM flavin or Ru (II)—tr is (2,2 -bipiiydine) was used as the photosensitizer and 20 mM semicarbazide as the electron donor. All solutions were in 1 M NaOH. The photochemical reaction was followed as previously described (Navarro et al., 1987b 1987c). 

Hammarstrom L, Sun L, Aakermark B, Styring S. A biomimetic approach to artificial photosynthesis Ru(II)-polypyridine photosensitizers linked tyrosine and manganese electron donors. Spectrochim Acta 2001 37 2145-60. 

Hammarstrom L, Styring S. Proton-coupled electron transfer of tyrosines in Photosystem II and model systems for artificial photosynthesis the role of a redox-active link between catalyst and photosensitizer. Energy Environ Sci. 2011 4 2379-88. 

A schematic cycle describing the principle of light capture and energy storage via a photosensitized electron transfer process In an artificial device Is presented In Figure 2. In this system a synthetic sensitizer, S, substitutes for the natural chlorophyll as the light capturing entity. Excitation of the sensitizer, followed by an electron transfer to electron acceptor. A, results In the oxidized sensitizer and a reduced species, A. Oxidation of an electron donor, D, recycles the sensitizer and produces an... 

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