Desvenlafaxine succinate monohydrate.

The title compound {systematic name: [2-(1-hydroxycyclohexyl)-2-(4-hydroxyphenyl)ethyl]dimethylammonium 3-carboxypropanoate monohydrate}, C(16)H(26)NO(2)(+) x C(4)H(5)O(4)(-) x H(2)O, is a succinate salt of O-desmethylvenlafaxine (desvenlafaxine). The present structure is one of four reported polymorphs of this salt, which is a new antidepressant drug. The carboxyl group of the succinate anion adopts a rare anti conformation and is engaged in a very short O-H...O(-) hydrogen-bond contact. Both cations and anions are involved separately in the formation of distinct O-H...O hydrogen-bonded networks. Desvenlafaxine cations and water molecules self-assemble to generate a honeycomb layer, while the succinate anions form a linear tape structure. These hydrogen-bonded networks are interlinked via N-H...O and O-H...O hydrogen bonds. The hydrogen-bonding network is so strong that desolvation and melting occur together at approximately 402 K. Thus, the crystal structure may be used to understand the thermal stability and solubility of the compound at the molecular level.