Substituent effect in the reaction of aryl arylmercury sulphides with picryl iodide

Abstract

The rates of the reaction of a series of substituted aryl arylmercury sulphides (Ar¹HgSAr²) with picryl iodide in benzene at 30° have been measured. Electron-donating substituents located in Ar¹ and in Ar² enhance the reaction rate whereas electron-withdrawing substituents have the opposite effect. The logarithmic plots of rate against σ constants give ρ values of –0.966 (substituents in Ar¹) and –3.67 (substituents in Ar²). o-Methyl groups in Ar¹ have little steric effect whereas o-methyl groups in Ar² strongly depress the reaction rate.