Cation Complexation Properties of Hexakis(2-O-methyl-3,6-anhydro)-α-cyclodextrin: A 1H NMR Study

Abstract The affinity of hexakis(2-O-methyl-3,6-anhydro)-α-cyclodextrin (3,6-α-CDM) for Ba2+, Pb2+, Ca2+ and Sr2+ has been tested by 1H NMR. It was shown that 3,6-α-CDM forms strong complexes in water with Pb2+ and Ba2+. The comparison with the parent hexakis(3,6-anhydro)-α-cyclodextrin bearing hydroxyl groups instead of methoxy groups reveals that the O-CH3 substitution significantly improves the anhydro-cyclodextrin selectivity.