TV-Halogen compounds

See Other TV-HALOGEN compounds, oxosalts of nitrogenous bases... 

An explosive oxidant, readily initiated by shock or phase change during condensation or evaporation. Only small samples should be used and at moderately low temperatures. See other DIFLUOROAMINO COMPOUNDS, TV-HALOGEN COMPOUNDS... 

See other ENDOTHERMIC COMPOUNDS, TV-HALOGEN COMPOUNDS, NITROSO COMPOUNDS, OXIDANTS... 

V-Halogenated compounds such as A-chlorotrifluoroacetamide, /V-chloro-lmidosulfuryl fluonde and NN dichlorotnfluoromethylamine add across C=C bonds toform saturated amides [14] imidosulfurylfluorides [15] and amines [16j, respectively Allylic halogenation also occurs with the use of TV-bromo- or /V-chlo roperfluoroamides The primary amine TV.TV-dichlorotrifluoromethylamine selectively affords 11 or 2 1 adducts with either tetrafluoroethylene or chlorotrifluoroethylene [76] (equation 7) The reaction mechanism is believed to involve thermal free radicals, with control achieved principally by reaction temperature The 1 1 adduct is formed even in the presence of a large excess of olefin... 

The validity of equation (12) has been checked for several families of alkyl halides for which D and E /x- are known (Ref. 32, see particularly figure 6 therein). It was thus found that for v = 0.1 V s the constant is equal to 0.3 eV at 20°C (expressing D in eV and the potentials in V). Equation (12) was then applied to the approximate determination of unknown BDEs in several series of compounds undergoing dissociative electron transfer, namely, TV-halosultams,32 sulfonium cations,33 vicinal dihalides,34 1,3-dihaloadamantes, 1,4-dihalo-bicyclo[2.2.2]octanes, and l,3-dihalobicyclo[l.l.l]pentanes.35 In the latter case, the mutual influence of the two halogens could be rationalized thanks to the conversion of the peak potential data to bond dissociation energies. 

Besides Pdp4 and the mixed valence compound Pd°[Pd p6] (see Section 3.1), the known halogen derivatives of Pd(TV) are the halocomplexes [PdXe] " (X = F, Cl, Br, I). Obtained by halogen oxidation (or, for [Pdle] ", addition of excess Csl to [PdCle] ), they have been crystallized with a variety of alkali metal cations. Cs2[Pdl6] has been also obtained in the solid state by application of pressure to samples of Cs2[Pdl4]-l2 ... 

Most TV-haloimidazoles and their benzo analogues are rather labile compounds, but the Af-iodo compounds are stable probably because the iodonium cation is more stable than other halogen cations. 1-Iodoimidazoles do not dissolve in acids or alkalies and decompose on heating with liberation of iodine. The rearrangement of N- to C-halopyrazoles has been observed and has also been postulated to occur with imidazoles TV-iodoimidazoles may be intermediates in the C-iodination process. 

Just as many palladium(IV) complexes are produced by halogen oxidation of the corresponding palladium(II) complex, so the palladium(TV) compounds tend to decompose by the reverse process, usually on heating ... 

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