Oxides Os

Figure 2.5 Schematic representation of the Au/MPS/PAH-Os/solution interface modeled in Refs. [118-120] using the molecular theory for modified polyelectrolyte electrodes described in Section 2.5. The red arrows indicate the chemical equilibria considered by the theory. The redox polymer, PAH-Os (see Figure 2.4), is divided into the poly(allyl-amine) backbone (depicted as blue and light blue solid lines) and the pyridine-bipyridine osmium complexes. Each osmium complex is in redox equilibrium with the gold substrate and, dependingon its potential, can be in an oxidized Os(lll) (red spheres) or in a reduced Os(ll) (blue sphere) state. The allyl-amine units can be in a positively charged protonated state (plus signs on the polymer...

Os (Tp)(NHPh)(Cl)2] exhibits low acidity and low basicity it is less acidic and less basic than aniline. It was suggested that this is a result of both Os— N(amide) tt bonding and the inductive effect of the oxidizing Os(IV) center. Reaction of [Os (Tp)(NHPh)(Cl)2] with MeOTf at 80 °C for 6T produces [Os (Tp)(NHPh)(OTf)2] and CH3CI. The X-ray structure of [Os (Tp)(NH-Ph)(OTf)2] shows a distorted octahedral structure Os— N(amido) = 1.939A and... 

For compound (Scheme 1 and Table 1) the oxidation pattern is quite different the differential pulse voltammetry exhibits two peaks of equal height, both corresponding to a two-electron oxidation process (Figure 11). The first oxidation occurs at nearly the same potential as the four-electron process of compound 6F. This shows that, as expected, the two Os(bpy)2( i-2,3-dpp) units are the first to be oxidised (Table 2). The second process concerns the oxidation of the two Ru(bpy)2(p-2,5-dpp) units. Since such units lie far away from the previously oxidized Os-containing units, their oxidation occurs at a potential (Table 2) close to that of the equivalent peripheral units of 6D. As in the case of the compounds 6A-F the oxidation of the two inner units are displaced outside the accessible potential window. 

Whan desired pure, it is usually prepared by decomposing sulphuric acid, by means of a metal not very easily oxidized, os mercury or copper. The meld combines with one equivalent of the oxygen of tho sulphuric acid, and the sulphur with the remaining two equivalents of oxygeo pass off ns sulphurous acid gas f the oxide obtained unites with lira suiphurio... 

DPL 10-30 Strong oxidant Os(bpy) + is accumulated in the inner cavities of the vesicles 87... 

The osmium starts as Os(VIII) and ends up as Os(VI)—the reaction is, of course, an oxidation, and it s one that is very specific to C=C double bonds (as we mentioned in Chapter 24). As written, it would involve a whole equivalent of the expensive, toxic, and heavy metal osmium, but it can be made catalytic by introducing a reagent to oxidize Os(VI) back to Os(VIII). The usual... 

Several oxidized compounds of iodine have been reported at various times. No doubt many of them are mixtures of iodic or periodic acids or anhydrides with iodine, etc. For example, there is (1) N. A. E. Millon s oz de sousk poiodtque, I10G19, i.e. I207,41a0s, formed os a yellow powder by the action of sulphuric acid on iodic acid. Mill on regarded this oxide os hypoiodic anhydride, Ia04 or 10 j, mixed with a little iodous... 

Larger amounts of some metals can be extracted as nitrates [U, Th, Ce(IV), Y, Se] or oxides (Os, Ru). Matrix yttrium or scandium are extracted with TBP from 12-13 M HNO3 [70],... 

Osmium is very infusible, and when it iias been ignited in close vessels, may be heated in air without oxidation. It is chiefly remarkable for forming with oxygen a volatile acid, which has a pungent smell, like that of chlorine, and is very poisonous. It forms, altogether, 6 oxides. Os 0, Os, 0, Os 0 Os 0, and Os O, 4 chlorides, and 4 sulphurets, corresponding to the 4 first oxides. 

Oxidation of l,l-bis(dialkoxyboryl)alkanes with MCPBA gives aldehydes, and similar oxidation oS 2,2-bis(dialkoxyboryl)sdkanes yields ketones. ... 

ELECTROCATALYSIS USING ELECTROACTIVE POLYMER FILMS film that is oxidized (Os(III)) is given by... 

Singlet oxygen (air, visible light and sensitizer) and benzyl phenyl selenide [which may be oxidized by O2 to the selenoxide, which may in turn oxidize Os(VI) back to... 

Conflicting reports have been made regarding the mercuration of pyridine 1-oxide. The substitution with mercuric acetate in acetic acid has been stated to give 76 per cent of 4-chloromercuripyridine l-oxide os but more recently has been convincingly demonstrated to proceed at the 2- and 2,6-positions204a. Mercuric halides give mainly 2-substitution, with some of the... 

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