High acidity disulphonyl carbon acids

Abstract

Four disulphonyl carbon acids, (PhCH₂SO₂)₂CHY (Y = H, Ph,p-CNC₆H₄,p- NO₂C₆H₄), have been synthesized and their ionization constants determined by spectrophotometric measurements in 80% (w/w) dimethyl sulphoxide- water at 25°C. The pK_a values, ranging from 11.65±0.02 to 7.75±0.02, present strong evidence for the conjugative effect of the two sulphonyl groups attached to the carbon acids.