Venlafaxine besylate monohydrate

The title compound {systematic name: [2-(1-hydroxycyclohexyl)-2-(4-methoxyphenyl)ethyl]dimethylazanium benzene­sulfonate monohydrate}, C₁₇H₂₈NO₂⁺·C₆H₅O₃S⁻·H₂O, is a besylate salt hydrate of the anti­depressant drug venlafaxine. In the crystal, besylate anions and water mol­ecules self-assemble, forming hydrogen-bonded dimers linked around inversion centers, with graph set R₄⁴(6). The crystal packing features a chain of alternate dimers and venlafaxine cations in the b-axis direction with the components linked by O—H...O hydrogen bonds and C—H...O and C—H...π inter­actions. This is the first example of a venlafaxine cation with a closed conformation, as it features an intra­molecular N—H...O inter­action involving the protonated N atom.