A sterically hindered bis(pyridylurea) species forms clathrates with water, methanol, and ethanol, all exhibiting unusual polar structures with Z′ > 1. This crystal packing is due to the hindered geometry about the urea oxygen acceptor atoms.

Chiral, tripodal anion hosts derived from either S-phenylalanine or S-leucine bind D-lactate enantioselectively. The nature of the host-guest interaction has been probed by solution NMR methods and by DFT calculations. The calculations suggest that the D-lactate may form an additional hydrogen bond in the host-guest complex while the L-lactate complex contains an intramolecular hydrogen bond. Anion binding is in competition with host dimerisation, as demonstrated by DOSY and (1)H NMR spectroscopy, and DFT calculations.

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