Complexation of oxygen

Cramer, W. A., et al., 1996. Some new structural aspects and old controversies concerning die cytochrome b /complex of oxygenic photosyndie-... 

It should be noted that dissociation of surface complexes of oxygen in polar solvents on semireduced ZnO films is presumably justified from the thermodynamic point of view as oxygen adsorption heat on ZnO and electron work function are [58] 1 and approximately 5 eV respectively while the energies of affinity of oxygen molecules to electron, to solvation of superoxide ion and surface unit charge zinc dope ions are 0.87, 3.5, and higher than 3 eV, respectively [43]. 

Nickel Complexes of Oxygen- or Nitrogen-Containing Ligands... 

The solid inclusion (clathrate) complex of oxygen with hydroquinone had been prepared twice previously by a published method which involved saturating a solution of hydroquinone in propanol in an autoclave at 70°C with oxygen at 20—150 bar,... 

The driving forces for electron transfer are a high-energy level of the highest occupied molecular orbital or a steric strain of the starting molecule. Complexation of oxygen by the electron-rich organic molecule has often been indicated as the first step of the mechanism. 

Complexes of oxygen nucleophiles or silyloxonium salts, for example,... 

Thus the explanation of the greater strength of metaphos-phoric acid HP03 compared with orthophosphoric acid H3P04, as a consequence of a difference in coordination number, is incorrect, since HPOs as such does not exist but forms polymeric ions built up from complexes of oxygen tetrahedra (Fig. 8). There is indeed a difference in the ratio O P in total. 

Ruthenium complexes of oxygen donor ligands incorporating other donor ligands are discussed in the corresponding section for the other ligand. Ternary and related compounds are outside the scope of this review. 

Cramer, W.A., Soriano, G.M., Ponomarey, M., Huang, D., Zhang, H., Martinez, S.E., and Smith, J.L. 1996. Some new structural aspects and old controversies concerning the cytochrome b(f complex of oxygenic photosynthesis. Annu. Rev. Plant Physiol. Plant Mol. Biol. 47 477-508. Deisenhofer, J., and Norxns,XR. (Eds.) 1993. The Photosynthetic Reaction Center Vols. 1 and 2. Academic Press, San Diego, CA. 

Gould, I. R., and Hillier, I. H., The relation between hydrogen-bond strengths and vibrational frequency. shifts A theoretical. study of complexes of oxygen and nitrogen proton acceptors and water, J. Mol. Struct. (Theochem) 314, 1-8 (1994). 

Kurisu G, Zhang H, Smith JL, Cramer WA. Structure of the cytochrome bgf complex of oxygenic photosynthesis tuning the cavity. Science 2003 302 1009-1014. 

Zhang H, Kurisu G, Smith JL, Cramer WA. A defined protein- 66. detergent-lipid complex for crystallization of integral membrane proteins The cytochrome b6f complex of oxygenic photosynthesis. Proc. Natl. Acad. Sci. U.S.A. 2003 100 5160-5163. 

Thermal oxidation is also autocatalytic and considered as metal-catalyzed because it is very difficult to eliminate trace metals (from fats and oils or food) that act as catalysts and may occur as proposed in Equation 4. Redox metals of variable valency may also catalyze decomposition of hydroperoxides (Scheme 2, Equations [6] and [7]). Direct photooxidation is caused by free radicals produced by ultraviolet radiation that catalyzes the decomposition of hydroperoxides and peroxides. This oxidation proceeds as a free radical chain reaction. Although there should be direct irradiation from ultraviolet light for the hpid substrate, which is usually uncommon under normal practices, the presence of metals and metal complexes of oxygen can become activated and generate free radicals or singlet oxygen. 

It is conceivable that excited oxygen and/or ozone molecules and charge-transfer complexes of oxygen molecules with polymers may be involved in the initiation step of photodegradation of polymers. 

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