1H and 13C nuclear magnetic resonance study of hindered rotation and acid–base exchange rates in benzaldehydes dissolved in superacid medium

Abstract

Using ¹³C and ¹H n.m.r. line shape analysis, the complex system of inter- and intra-molecular exchange rates in p-chlorobenzaldehyde dissolved in superacidic medium has been investigated. The effect of proton exchange on the measured barrier to internal rotation in the protonated species is shown and the population unprotonated benzaldehyde has been estimated.