Reactions with Halide Ions

The halogen atom on organic halides may undergo exchange reactions with halide ions on boron halides ... 

The gold phosphine fragment has also been abstracted from heteronuclear cluster compounds as Au(PR3)X by reaction with halide ions... 

Eberson and co-workers have recently discussed the probability that the interaction of ion-radicals with nucleophiles and electrophiles is subject to orbital symmetry constraints.31,32 This follows the observation that with perylene the cation-radical (18) the preferred course of reaction with halide ions is electron transfer rather than nucleophilic addition, whereas with the phenothiazine cation-radical (19) nucleophilic attack by Cl" and Br occurs. 

For reaction with hydrogen halides, the substitution reaction with halide ion easily occurs when a cuprous or cupric compound is used as the catalyst (23) and yields a halogenated allyl compound. With a cuprous compound as the catalyst at 18 °C, the reaction is completed in 6 h. Zinc chloride is also a... 

In aqueous solution, astatine is usually found in the free (0) state. However, unlike the other halogens, astatine(O) is not diatomic. It can be volatilized from solution and extracted (like iodine) into organic solvents such as benzene and carbon tetrachloride. Coextraction with halogens, X2, into chloroform produces interhalogen compounds, AtX (X = Cl, Br, I). Reaction with halide ion, X , yields polyhalide ions, AtX2 (X = Br, I) and AtIBr , which can be extracted into isopropylether. 

Similar conclusions were reached in a second paper dealing with the pulse-radiolytic reduction of Cd + alone. Further reactions of these ions are the subject of another paper and, besides electron-transfer processes, additions of unsaturated compounds and oxygen atom transfers from NgO are described. The products of these latter reactions, MO+, behave like OH in their reactions with halide ions. In the electron-transfer processes, the reactions with peroxodisulphate proceed by a second-order pathway with rate constants of ca. 10 1 mol s ... 

Aquated metal ions tend to group into two categories in their reactions with halide ions.27a One class favors reactions with small, unpolarizable bases (e.g. fluoride ion) and the other favors reactions with large, polarizable bases (e.g. iodide ion). Swarzenbach referred to these classes of metal ions as... 

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