P-oxygen

P oxygen transfer, presumably via (9). The structure of (10) was confirmed by X.-ray analysis and hydrolysis to give (11). An X-ray analysis of isopropylidenetri(isopropyl)phosphorane (12) suggests that the ylide P-C bond is relatively longer, and that the... 

Electron- 37 precise, P oxygen-centered Li SiMe2(CMe2Pri) 20 1 6 6 49... 

Sample Inherent Viscosity dl/g %P Oxygen Level for Burn lime of ... 

Table 2 Initial reaction rates and normalized reaction rates (between brackets) of alcohols and amines using a normal acyl donor or a p-oxygen-activated acyl donor[28]...

Fig. 11.3. Pharmacophoric triangle detection. The dotted lines define a triangle comprising three features piHydrophobic (H=, centroid of benzene), piAcceptor (A=, oxygen of carboxylic acid), and piPolar (P=, oxygen of hydroxyl), and the shortest bond path between each pair of features is 2 (A= to H=), 1 (P= to H=), and 4 (A= to P=). Reprinted ( adapted or in part ) with permission from Journal of Chemical Information and Modeling. Copyright 2008 American Chemical Society.

In the case discussed here a Mott transition is unlikely the Hubbard U deduced from the Neel temperature is not relevant if the carriers are in the s-p oxygen band, but if the carriers have their mass enhanced by spin-polaron formation then the condition B U for a Mott transition seems improbable. In those materials no compensation is expected. We suppose, then, that the metallic behaviour does not occur until the impurity band has merged with the valence band. The transition will then be of Anderson type, occurring when the random potential resulting from the dopants is no longer sufficient to produce localization at the Fermi energy. 

Alkenes from p-oxygenated selenidesS /J-Phenylseleno lactones, ethers, and alcohols are converted into alkenes on treatment with ClSi(CHj)j and Nal in C HiCN. Hydriodic acid (formed by inadvertent hydrolysis) may play a role this acid cun effect this reaction, but in lower yield. This elimination thus reverses cyclo-(unclionali/ations induced by C6H5ScX (cf Na-NH3, 9, 26), and in addition provides a stereospecific route to alkenes by way of/l-hydroxv selenides. lixnmplc ... 

RothJ. P. Oxygen isotope effects as probes of electron transfer mechanisms and structures of activated 02. Acc. Chem. Res. 2009, 42, 399-408. 

Lanci M. P. Roth J. P. Oxygen isotope effects upon reversible 02-binding reactions characterizing mononuclear superoxide and peroxide structures. J. Am. Chem. Soc. 2006,... 

Other investigations with flexible models led to the conclusion that in confor-mationally unrestricted systems, there is no significant p-oxygen effect168 in the... 

Lessler, M. A. Brierley, G. P. Oxygen electrode measurements in biochemical analysis. Methods Biochem. Anal., 1969, 17, 1-29. 

Further experiments have shown that this effect is due to the oxygen-function at C-2, as similar alkoxy cyclopropanes display the same behaviour 69). Therefore the term syn-oxyphily has been suggested for this unusual phenomenon, the explanation of which is still speculative. Since it operates against pure steric effects, it must be of electronic nature with the P-oxygen as the key element. 

The formation of the lithium enolate is straightforward but it might be expected to be unstable because of a simple elimination reaction. It is not possible to make open-chain lithium enolates with P oxygen substituents like this because they do undergo elimination. 

Gaspar, A., Evtuguin, D. V, and Neto, C. P., Oxygen bleaching of kraft pulp catalysed by Mn(III)-substituted polyoxometalates. Appl Catalysis A-General 2003, 239 (1-2), 157-168. 

Taylor, H. P. Oxygen and hydrogen isotopes in petrology. In Minerals, rocks and inorganic materials, in press. Berlin-Heidelberg-New York Springer 1973. 

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