Crystal structure of memantine–carboxyborane

The synthesis and crystal structure of the title compound, C13H24BNO2 [systematic name: 3,5-dimethyladamantanylamine–boranecarboxylic acid or N-(carboxyboranylidene)-3,5-dimethyladamantan-1-amine], derived from the anti-Alzheimer's disease drug memantine is reported. The C—N—B—CO2 unit is almost planar (r.m.s. deviation = 0.095 Å). The extended structure shows typical carboxylic acid inversion dimers linked by pairwise O—H...O hydrogen bonds [O...O = 2.662 (3) Å]. The amino group forms a weak N—H...O hydrogen bond [N...O = 3.011 (3) Å], linking the dimers into [001] chains in the crystal. Highly disordered solvent molecules were treated using the SQUEEZE routine of PLATON [Spek (2015). Acta Cryst. C71, 9–18], which treats the electron density as a diffuse contribution without assignment of specific atom locations. A scattering contribution of 255 electrons was removed. The crystal studied was refined as a two-component twin.