Photoreactivity environmental effects

Photopolymerizable coatings relief-image-forming systems, 6,125 Photoreactivity environmental effects, 1, 394 Photoredox properties bipyridyl metal complexes, 2, 90 Photoresist systems, 6,125 Photosensitive materials, 6, 113 Photosynthesis anoxygenic, 6, 589 magnesium and manganese, 6, 588 water decomposition models, 6, 498... 

The next section devoted to the quantum chemical methods and concepts gives a survey of the computational schemes and theoretical tools adapted to the investigation of electronic spectroscopy and photoreactivity in transition metal complexes. The solvent and other environmental effects are not discussed here and are not taken into account in the selected applications described in the later sections dedicated to the electronic spectroscopy and photoreactivity, respectively. 

Roca-Sanjuan D et al (2009) DNA nucleobase properties and photoreactivity modeling environmental effects. Pure Appl Chem 81 743-754... 

Photolysis of a carbonyl compound having y-hydrogen commonly gives a shorter chain carbonyl compound, an alkene, and a cyclobutanol, which are formed from a 1,4-biradicaP produced via y-hydrogen abstraction by the excited carbonyl. The photoreactions derived from the 1,4-biradical are termed the Norrish type 11 reaction, and those involving intramolecular hydrogen abstraction from y- and other positions are generically referred to as the type II family. The chemical behavior of the 1,4-biradical determines the type 11 reactivity of carbonyl compounds. In this chapter, the influence of environment on the formation and behavior of the 1,4-biradical from simple alkyl aryl ketones will be described. Environmental effects on the type 11 reaction have been reviewed. ... 

Burns, S. E., J. P. Hassett, and M. V. Rossi. 1996. Binding effects on humic-mediated photoreaction Intrahumic dechlorination of Mirex in water. Environmental Science and Technology 30 2934. 

Among various reports of relevance to environmental chemistry, the finding by Wallace et al. that tropospheric concentrations of ozone are increased near the plumes of power plants emitting sulphur dioxide is of particular interest. The effect is not caused by photoreactions of SO2 alone, but occurs with SO2 in the presence of CI2. A chain process involving ClOO radicals may be involved. Of more distant relevance is the observation by Ferris and Benson that photolysis of PHj to P2H4 appears to play a part in the atmospheric photochemistry of the planet Jupiter. 

Recent work on the role of solvated electrons in intra-DOM reduction processes has demonstrated the importance of trapped e in reactions with species adsorbed on the DOM matrix [98-100]. Modeling of DOM mediated photoreactions indicated the importance of sorption of molecules to DOM for reaction to occur [98, 99]. This is consistent with the lifetime of e" precluding escape from the aqueous DOM matrix into bulk solution. Since many important reactions with environmental implications involve binding or adsorption to DOM - see, for example, [3,101,102] - the role of matrix effects and the caged electron could be very significant. Some workers have suggested that since e remains primarily trapped within the DOM matrix, Oj must be formed by direct electron transfer from the excited triplet state of DOM to O2 [14]. However, it is equally if not more plausible that Oj may be produced by the reduction of Oj by radicals or radical ions produced by intramolecular electron transfer reactions from irradiated DOM [25]. The participation of radicals in the production of carbonyl sulfide and carbon monoxide from irradiated DOM in South Florida coastal waters was recently demonstrated by Zika and co-workers [81-83] and potential pathways for the formation of free radicals from irradiated DOM were discussed. Clearly, the relative contribution of e q and associated transients to the photochemistry of DOM has not been unequivocally resolved in the literature. 

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