Substituent effect on the nucleophilic replacement of bromine by astatine and iodine in m- and p- substituted bromobenzenes

It has been shown that the logarithms of relative yields of astatobenzenes, with the exception of p-nitro-bromobenzene, are in correlation with the Hammett substituent values. The substitution reaction parameter was found to be -0.59 and 0.0 for substituted astatobenzenes and iodobenzenes, respectively. They allow to make a conclusion about a two-step process of nucleophilic replacement of bromine by astatine and iodine in bromobenzene and its substituted compounds diluted with an amine. (author)