33S NMR spectra of some sulfonated naphthalenes, naphthols, and their anions

Abstract

The 33S NMR spectra of 11 naphthalenesulfonates, 11 hydroxynaphthalenesulfonates, two dihydroxynaphthalenesulfonates, and their anions have been measured in aqueous solutions. The 33S NMR chemical shifts of these compounds exhibit upfield shifts when related to ammonium sulfate as the standard. Introduction of a further sulfonic group causes a small upfield shift (up to 3 ppm). Introduction of a hydroxyl group causes a downfield shift (up to 5 ppm) unless the ring is further substituted. Formation of the anion from hydroxyl group causes an additional downfield shift (up to 6 ppm). The half-width of 33S NMR signals of sulfonated naphthalenes, naphthols, and their anions vary from 10 to 400 Hz.