Oxygenation deoxygenation

Photolysis of 1,4-diphenylphthalazine 2-oxide in various solvents gives 1,3-diphenyl-isobenzofuran (52) as the primary product. In the presence of oxygen, deoxygenation to 1,4-diphenylphthalazine and oxidation of the initially formed 1,3-diphenylisobenzofuran (52) to 1,2-dibenzoylbenzene also take place (Scheme 17). 

Fig. 22. Oxygen uptake by polymer-hone complexes (cycle of oxygenation-deoxygenation)98 ...

Owing to its physiological importance the oxygenation-deoxygenation process in hemoglobin has been widely investigated, but it is beyond the purposes of the present paper to give an account of the studies so far reported (see e.g. Ref. 127 for recent reviews), except for some main aspects. 

More recently Perutz (PIO) has proposed a stereochemical mechanism of heme-heme interaction which describes in detail the cooperative effects in hemoglobin. Most important in the oxygenation-deoxygenation... 

Vladisavljevic G.T., Use of polysulfone hollow fibres for bubbleless membrane oxygenation/deoxygenation of water,... 

The major reactions in this section are those involving an V-oxide oxygen. Deoxygenation of 2,3-disubstituted quinoxaline 1,4-dioxides is achieved under mild conditions by treating with hexa-chlorodisilane, TMS-1, TFAA-sodium iodide, or titanium tetrachloride-zinc dust <81H(i6)4ii>. Quinoxaline and phenazine V,A( -dioxides are also deoxygenated under mild conditions by sodium hypophosphite catalyzed by Pd/C or by treatment with sodium iodide in the presence of pyri-dine/sulfur trioxide complex <83JHC1735>. Deoxygenation of 6-chloro-2(l//)-quinoxalinone 4-oxide is effected particularly by sodium borohydride or sodium hydrosulfite <85H(23)143>. 

Hemoglobin plays a part in a series of equilibria involving protonation-deprotonation and oxygenation-deoxygenation. The overall reaction is approximately as follows ... 

As these reactions are irreversible, the bridged oxo- iron(III) porphyrins (26) will be lost for the oxygenation/deoxygenation cycle. This is manifested in the rapid gradual loss of O -binding capacity. 

The extent of the interconversion is visualized in Fig. 19.4. (Here species B is an impurity phase-related component that shows up when the sample is subjected to several oxygenation-deoxygenation cycles.) The phenomenon has been simply referred to as B to C conversion. ... 

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