The title diastereomeric salt, formed between 2-amino-1,2-di-phenyl-ethanol (ADE) and aspartic acid (ASP), C14H16NO+·C4H6NO4-·H2O, crystallizes as a monohydrate. The 1,2-di-phenyl-ethyl group in the cation has a cis conformation, and the aspartic acid anion is in the zwitterionic form. In the crystal, the ASP anions are linked via N-H⋯O hydrogen bonds to form a 21 helix along the b-axis direction. The helices are linked by the ADE cations via O-H⋯O and N-H⋯O hydrogen bonds, forming layers parallel to the bc plane. There are channels in the layers that are occupied by water mol-ecules, which link to both the anions and cations via Owater-H⋯O and N-H⋯Owater hydrogen bonds. There are also C-H⋯O and C-H⋯π inter-actions present within the layers.
Keywords: crystal structure; diastereomeric salt separation; helical columnar structure; intermolecular hydrogen bonding; zwitterion.