CHARACTERIZATION OF SULFOBETAINE MONOMERS BY NUCLEAR-MAGNETIC-RESONANCE SPECTROSCOPY - A NOTE

A set of zwitterionic monomers bearing the 3-ammoniopropanesulfonate m oiety is analysed in CDCl3, CD3OD and D2O by one- and two-dimensional H-1 n.m.r. and C-13 n.m.r. spectroscopy. Absolute and relative positio ns of the n.m.r, signals are determined depending on the solvent used; the refined assignments of the signals in the vicinity of the ammoniu m group deviate from previously proposed assignments based on standard n.m.r, shift tables. Still, there is no convincing evidence for a spe cial ring current effect due to a six-membered ring conformation of th e betaine moiety.