Isolation of an Acid/Base Complex in Solution Puts the Brakes on Nitrogen Inversion

An introverted carboxy functionality of the cavitand shown, significantly alters the dynamics of nitrogen inversion of guest molecules, as well as the hydrogen bonding and guest tumbling in the inner recess. For example, NMR experiments indicate that N-inversion of ethylmethylisopropylamine is several orders of magnitude slower in the cavitand than the rate observed in solution.