Selective functionalisation. Part 4. 1H Nuclear magnetic resonance studies of the orientation of aromatic molecules by surfactant micelles

Abstract

The ¹H n.m.r. spectra of phenol and anisole in the presence of anionic and cationic detergents are described. The spectra are characterised by differential upfield shifts of the protons of the solubilisate as the detergent concentration is increased. Evidence is presented to show that, although the upfield shifts are sensitive to pH and to the head group of the detergent, the major cause of the differential upfield shift is a time-averaged orientation of the solubilisate in the micellar environment. The significance of these results with respect to micellar control of regioselectivity in aromatic substitution is discussed.