Oxy metalation

An improved adsorption of DNA bases has been observed at a chemically modified electrode based on a Nafion/ruthenium oxide pyrochlore (Pb2Ru2-x FhxOj-y modified GC (CME). Nafion is a polyanionic perfiuorosulfonated ionomer with selective permeability due to accumulation of large hydrophobic cations rather than small hydrophilic ones. The Nafion coating was demonstrated to improve the accumulation of DNA bases, while the ruthenium oxide pyrochlore proved to have electrocatalytic effects towards the oxidation of G and A. The inherent catalytic activity of the CME results from the Nafion-bound oxide surface being hydrated. The catalytically active centers are the hydrated surface-boimd oxy-metal groups which act as binding centers for substrates [50]. 

I and II metals, oxy-metal ions and metal cyanide complexes (used in conjunction with MMS) ... 

Constant of proton affinity to hydroxy(oxy)metal complex K—is connected with undersaturation of the oxygen atom valency as follows ... 

Mechanistic hypotheses play an important role in developing new catalytic and selective heterofunctionalizations of alkenes. Two basic reaction cycles for metal-catalyzed hydroalkoxylation (and hydration, for R = H) of alkenes can be postulated (Scheme 2). One pathway leads to Markovnikov products via activation of the nucleophile, oxy-metallation, and protonolysis (hydro-de-metallation) (Scheme 2a). Alternatively to the inner sphere syn-oxymetallation depicted in Scheme 2a, external anti-attack of the nucleophUe to coordinated olefin is plausible. The oxidation state of the metal remains constant in this cycle. The alternative hydrometallation pathway (Scheme 2b) proceeds via oxidative addition of the H-OR bond, hydrometallation of the olefin, and reductive elimination to the anti-Markovnikov addition product [3,4]. 

The metal-catalyzed transvinylation of vinylacetates or vinyl ethers with alcohols is initiated by an oxy-metallation reaction. With PdCl2(PhCN)2 as the catalyst and at low temperature, transvinylation takes place exclusively (Scheme 5a). At higher temperatures, acetal formation is observed after an induction period, in addition to precipitation of palladium (Scheme 5b). It is probable that the acetaliza-tion step is catalyzed exclusively by traces of Brpnsted acid (HCl), rather than via proto-de-metallation of a Pd(II) alkyl species [21, 22]. Consequently, a recent report on the protection of primary alcohols as tetrahydropyranyl- (THP-)ethers by addition to 2,3-dihydropyrane in the presence of PdCl2(MeCN)2 as catalyst... 

PF King, DD Fekete, US Patent US 3969135 to Oxy Metal Industries Corp, 1976. 

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