PROTON-LIGAND STABILITY CONSTANTS OF SUBSTITUTED 2-AMINOPHENOLS

The proton-ligand stability constants of 2-aminophenol and its nuclear substituted derivatives such as 4-Nitro, 5-Nitro, 6-Nitro, 4-Chloro, 4-Sulphonic acid, 4-Arsonic acid, 4-Phenyl, 4-Amino, 3-Hydroxy and 4-6-Dinitro 2-Aminophenols are determined in 50 per cent water-dioxan mixtures at 30°C and at μ = 0·1, employing the Calvin-Bjerrum pH titration technique. The values are compared with those predicted from the pK variations of substituted benzene compounds listed by H. C. Brown et al. The results are discussed in view of the electrostatic and resonance effects and the anomalies are explained. © 1969.