Tramadol hydrochloridebenzoic acid (1/1)

Abstract

In the cation of the title cocrystal salt {systematic name: [2-hydroxy-2-(3-methoxyphenyl)cyclohexylmethyl]dimethylazanium chloridebenzoic acid (1/1)}, C 16H 31NO 2+· Cl -·C 7H 6O 2, the N atom is protonated and the sixmembered cyclohexane ring adopts a slightly distorted chair conformation. The dihedral angle between the mean planes of the benzene rings in the cation and the benzoic acid molecule is 75.5 (9)°. The crystal packing is stabilized by weak intermolecular O - H⋯Cl, N - H⋯Cl and C - H⋯π interactions, forming a twodimensional chain network along the b axis. The benzoic acid molecule is not involved in the usual headtotail dimer bonding, but instead is linked to the ammonium cation through mutual hydrogenbonding interactions with the chloride anion.