Substituent effects of positive poles in aromatic substitution. Part IV. The effects of the nitrogen, phosphorus, arsenic, and antimony poles on the orientation and rate of nitration

Abstract

The reactivity of the quaternary ions PhXMe₃⁺, where X = N, P, As, or Sb, to nitration in sulphuric acid increases steadily with the atomic weight of the atom bearing the formal charge. The amount of para-substitution is greater for the NMe₃⁺ group than for the SbMe₃⁺ group and passes through a minimum with the phosphorus and arsenic poles. In contrast, the amount of ortho-substitution is much greater for the antimony pole than for the nitrogen pole. These results are discussed in terms of the –M effect of the phosphorus, arsenic, and antimony poles.