Anti-inflammatory drugs .3. Salts of diclofenac with N-(2-hydroxyethyl)piperidine, N-(2-hydroxyethyl)morpholine and N-(2-hydroxyethyl)piperazine

The molecular and crystal structures of three salts of the same anion, N-(2-hydroxyethyl)piperidinium 2-(2,6-dichlorophenylamino)phenylacetate, C7H16NO+.C14H10-Cl2NO2-, N-(2-hydroxyethyl)morpholinium 2-(2,6-dichlorophenylamino)phenylacetate, C6H14NO2O+-C14H10C12NO2-, N-(2-hydroxyethyl)piperazinium 2-(2,6-dichlorophenylamino)phenylacetate, C6H15N2O+.C14H10C12NO2-, have been determined by X-ray diffraction. Strong anion-cation interactions via hydrogen bonds are the prime driving force for crystal self-assembly. Packing is determined by weak hydrogen-bonding interactions (C-H ... O and C-H ... Cl). The three compounds are isomorphous and are characterized by the same network of hydrogen bonds. Structural results are related to the different solubilities of the three salts.