High-valency metals

Fluorination of organic compounds using high valency metallic fluorides (14) may be represented as follows ... 

Perovskites have the chemical formula ABO, where A is an 8- to 12-coordinated cation such as an alkaU or alkaline earth, and B is a small, octahedraHy coordinated high valence metal such as Ti, Zr, Nb, or Ta. Glass-ceramics based on perovskite crystals ate characteri2ed by their unusual dielectric and electrooptic properties. Examples include highly crystalline niobate glass-ceramics which exhibit nonlinear optical properties (12), as well as titanate and niobate glass-ceramics with very high dielectric constants (11,14). 

For the past 20 years, four mam ways of replacement of hydrogen by fluorine have been used fluorination using elemental fluorine, electrochemical fluon nation, fluorination using high-valency metal fluorides, and selective electro philic fluorination... 

High-valency metal fluoride fluorination of pyridine [82JFC(21)171], quinoline [82JFC(21)413], and 2-methylfurans [91 JFC(51)179] has been reported. With 2-methylfuran a complex mixture of stereoisomers of partially fluorinated oxolans was obtained. These can be dehydrofluorinated to fluorooxolens and no furans have been observed. Conformation and structural group were found to influence the direction and readiness toward dehydrofluorination [91 JFC(52) 165]. 

The Exhaustive Fluorination of Organic Compounds by High Valency Metal Fluorides, M. Stacey and J. C. Tatlow, Adv. Fluorine Chem., 1 (1960) 166-198. 

Fluorofullerenes have been prepared by reaction with halogen fluorides, by direct fluorination with F2 or by fluorination with noble gas fluorides [7,8,14], The reaction with high valence metal fluorides is the most versatile route for the synthesis of CsoFnH. 

In the previous sections of this review, it has been shown that most effective catalysts for the selective oxidation of propylene contain at least two types of metal oxides—an amphoteric or low-valence oxide, such as bismuth, tin, iron, or cobalt, and an oxide of a high valence metal, such as molybdenum or antimony. Moreover, it has been suggested several times that each of these metal oxide components may give rise to an active site for example, propylene may adsorb on an active site associated with one of the metal oxide components, and oxygen may adsorb on an active site associated with another metal oxide component. This problem has been studied using spectroscopic, adsorption, and kinetic techniques. It now seems appropriate to consider some of these studies in detail, attempting to relate the solid structure of the catalyst to the active sites wherever possible. 

This combination [HO-/Pt—H(s), H2] is a strong one-electron reductant that will react spontaneously with most oxidants [02, HOOH, high-valence metal oxides (MnIV02, Fein203, Agr20, CunO, MnvuC>4, Cr O2-)]. As a result, these represent interferences to the voltammetric determination of dissolved H2 concentrations. 

Silver has three synthetically useful oxidation states Ag(I), Ag(II), and Ag(III).16 Free Ag(III) is very unstable, and most currently known Ag(III) complexes are stablized with electron-donating and/or sterically demanding ligands.17 It is known that Ag(I) can be oxidized to Ag(II) with strong oxidants such as persulfates. Nitrogen-based ligands such as pyridines are commonly used to stabilize high-valence metal ions.18 In 2003, He and coworkers utilized a pyridine-supported silver catalyst and reported the first silver-catalyzed aziridination of olefins.19... 

Fluorination of Q or C2 compounds by the high valency metallic fluoride. 

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