Direct Observation of the Li+–18-Crown-6 Complex Working as H2O Capture in Acetone– Water Mixture

The complex formation of alkali metal ion (Li+ or Na+) with 18-crown-6 in an acetone–water mixed solvent was studied by means of the specially designed mass spectrometer. The Li+–18-crown-6 complex can hold one H2O in its cavity in the mixed solvent, whereas the Na+–18-crown-6 complex hardly holds an H2O.