Amitriptylinium picrate: conformational disorder

In the structure of the title salt systematic name: 3‐(10,11‐dihydro‐5H‐dibenzoa,d]7]annulen‐5‐ylidene)‐N,N‐dimethylpropan‐1‐aminium 2,4,6‐trinitrophenolate] of a tricyclic antidepressant, C₂₀H₂₄N⁺·C₆H₂N₃O₇⁻, the dimethylaminopropyl subunit possesses a classical static conformational disorder. The central cycloheptadiene ring adopts a bent conformation that is intermediate between boat and chair forms, leading to a butterfly shape for the hetero‐tricyclic moiety. In a complementary fashion, donors from amitriptyline and acceptors from picrate form intermolecular C—H...O hydrogen bonds and N—H...O salt bridges. These hydrogen bonds cluster amitriptyline and picrate ions into a closed R₄⁴(36) hetero‐tetramer, whereas intermolecular C—H...π interactions between amitriptyline ions cluster them into homo‐dimers. Significant π–π stacking interactions are also observed between aromatic rings of amitriptyline and picrate, and these, combined with the C—H...π interactions, associate molecules into linear arrays along the 11] direction.