Multi-Component Hydrogen-Bonding Assembly of a Pharmaceutical Agent Pamoic Acid with Piperazine or 4,4′-Bipyridyl: A Channel Hydrated Salt with Multiple-Helical Motifs vs a Bimolecular Cocrystal

Assembly of pamoic acid (H(2)PA) with piperazine (PIPO) or 4,4'-bipyridyl (BIPY) results in two distinct supramolecular complexes [(PA)center dot(H2PIPO)]center dot 3H(2)O (1) and [(H(2)PA)center dot(BIPY)] (2). The former displays triple-helix host arrays via charge-assisted N+-H center dot center dot center dot O- interactions with the inclusion of helical water chains, whereas the latter represents the first cocrystal of pamoic acid sustaining by the familiar carboxyl-pyridyl H-bonding synthons. Notably, the structure of 1 can be dehydrated/rehydrated with retention of crystallinity.