Oxidation by Halogen

In an analogous fashion the oxidative coupling of 1,3-diselenols is used for the preparation of 1,2-diselenolanes, the precursors being obtained by a variety of methods (see Chapter 4.35). Similar reaction s have been used for the preparation of 1,2-thiaselenolanes. Substituted propane-1,3-diselenones (287) are oxidized by halogen to the corresponding 3,5-diamino-l,2-diselenolylium chloride (288) (67AJC1991). 

Nitrosyidisulfonic acid, reaction mechanisms, 22 129, 130 Nitrous acid, 33 103 decomposition, rate constants, 22 157 as oxidizing agent, 22 133 reaction mechanisms, 22 143-156 electrophilic nitrosations, 22 144-152 with inorganic species, 22 148, 149 nitrite oxidation by metals, 22 152-154 oxidation by halogens, 22 154, 155 in solution, 22 143, 144 reduction by metals, 22 155, 156 Nitrous oxide reductase, 40 368 Nitroxyl, reaction mechanisms, 22 138 Nitrozation, pentaamminecobalt(III) complexes, 34 181... 

Sulfur-linked substituents are usually prone to oxidation by halogens. In aqueous solution, chlorine converted 5-amino-3-benzylthio-1,2,4-thiadiazole successively into sulfoxide and sulfone, but in glacial acetic... 

There are two general procedures for the preparation of monomeric W11 complexes.269 In one, substituted tungsten carbonyls are oxidized by halogens under controlled conditions as exemplified by equations (18) and (19). In the second, W(CO)6 is first oxidized by Cl2 or Br2 at low temperature, followed by reaction of the oxidized product with the appropriate ligands. This preparative procedure is exemplified by equation (20). 

Long ago oxidation by halogens was mainly related to reactions of ligands, metals, and molecular iodine or bromine in acetonitrile or DMF [513]. The oldest example of these reactions is the transformation (3.262) [648] ... 

Carbonyl derivatives of iron(II) exist. Pentacarbonyl-iron(O) is oxidized by halogens to give carbonyl halide complexes (equation 35). The stability of these compounds with respect to thermal decomposition and hydrolysis increases in the sequence Cl < Br < I. 

While bridging carbonyl and hydrido ligands are often present in metal metal bonded dimers, halogens are probably the most common bridging ligands. Oxidation by halogens under controlled conditions leads to the Mo -bridged dimers as shown in equation (13). 

Several organoarsenic(III) compounds containing arsenic(III)-transition metal bonds have been oxidized by halogen-based electrophiles or by elemental sulfur to give the corresponding dihalides or sulfides (equations 365 , 366 and 367 - ). 

As shown in Eq. (42), polymers containing the TTF structure are synthesized by this method. Their charge-transfer complex formation with some acceptors and oxidation by halogens have been examined. 

Oxidation by halogens is of particular interest to us partly because we know more about it than the other reactions of methane—and, in one way or another, is the topic of discussion throughout the remainder of this chapter. 

The group IIA metals are oxidized by halogens and all the alkaline earth dihalides are known h... 

Cr(CO)6 is resistant to oxidation by halogens, unlike its Mo and W analogues. No reaction occurs with Br2 or I2 at RT CI2 effects oxidation to CrCla and phosgene. On the other hand, substitution of the carbonyl ligands by weaker tr-acid donors, such as bipyridine, thio ethers, or arsines, leads to complexes that are more easily oxidized. In some cases, such as Cr(CO)4L (L2 = 2,2 -bipyridine or 2,5-dithiahexane ), spectro-photometric changes and loss of CO are consistent with oxidation by Br2 and I2, though no isolable complex was obtained. If L is bis(l,2-dimethylarsino)benzene (diars), oxidation to Cr(diars)X3 (X = Br, I) occurs these Cr(III) complexes are likely dimers . ... 

In other cases, oxidation by halogens occurs without loss of a ligand, allowing formation of seven-coordinate, eationic products ... 

Pd(II) or Pt(II) are oxidized by halogens to their tetravalent analogues, [ML2X4], often as a mixture of cis and trans isomers. This reaction may be reversed by heating, but it is accompanied by extensive decomposition. Oxidative addition of Brj to cis- or trans-[PtBrMeL2] or cis-[PtMe2L2] proceeds rapidly and without cleavage of the Pt—Me bonds " ... 

Radon is oxidized by halogen fluorides (e.g. CIF, CIF3) to the non-volatile Rnp2 the latter is reduced by H2 at 770 K,... 

Bisdimethylaminofluorophosphine and alkyl- or aryldialkylamino-fluorophosphines can also be readily oxidized by halogens (86)... 

Oxidations in Bronsted Acid Media Oxidation by Lewis Acids Oxidation by Halogens Use of Metal Salts. ... 

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