Addition of Other Cations to Hydrocarbons

From the solubilities of aromatic hydrocarbons in aqueous silver nitrate it is clear that there, is an interaction with the silver ion to give monoargentated and, to a lesser extent, diargentated hydrocarbons. The bond to silver ion is probably of the rc-type, since the differences in the association constants for the complex with the three isomeric xylenes are small and since a single methyl group stabilizes the complex almost as much as two.279 

The argentation of olefins at 25° is more nearly complete than is the argentation of aromatic hydrocarbons and also differs in that alkyl substituents decrease rather than increase the stability of the com- 

A cyclic complex derivable by addition of positive bromine to a double bond has already been discussed as an example of the neighboring group effect. The same intermediate, except perhaps for the nature of the bonds to bromine, is formed in the addition of bromine to olefins and is responsible for the stereochemistry of the addition reaction and the nature of the by-products.232 

Competition with the bromide ion by solvent and by other ions for the intermediate bromonium ion explains the formation of such by- 

No product has as yet been isolated that is believed to have the bromonium ion ring intact, but some closely related ionic compounds are known. The latter compounds could have the bromonium and iodonium structure but their colors and the probable stability of the alternative carbonium, ion make it unlikely.282 

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