Memantinium chloride 0.1-hydrate

The crystal structure of the title compound, C12H22N+·Cl−·0.1H2O, consists of (3,5-dimethyl-1-adamantyl)ammonium chloride (memantinium chloride) and uncoordinated water molecules. The four six-membered rings of the memantinium cation assume typical chair conformations. The Cl− counter-anion links with the memantinium cation via N—H⋯Cl hydrogen bonding, forming channels where the disordered crystal water molecules are located. The O atom of the water molecule is located on a threefold rotation axis, its two H atoms symmetrically distributed over six sites; the water molecule links with the Cl− anions via O—H⋯Cl hydrogen bonding.

The crystal structure of the title compound, C 12 H 22 N + ÁCl À Á-0.1H 2 O, consists of (3,5-dimethyl-1-adamantyl)ammonium chloride (memantinium chloride) and uncoordinated water molecules. The four six-membered rings of the memantinium cation assume typical chair conformations. The Cl À counteranion links with the memantinium cation via N-HÁ Á ÁCl hydrogen bonding, forming channels where the disordered crystal water molecules are located. The O atom of the water molecule is located on a threefold rotation axis, its two H atoms symmetrically distributed over six sites; the water molecule links with the Cl À anions via O-HÁ Á ÁCl hydrogen bonding.
In the asymmetric unit of the crystal structure of the title compound, there are one mamentinium cation, one Clanion and 0.10 lattice water molecule. The expected proton transfer from hydrochloric acid to N1 atom of amino group occurs.
The four six-membered rings of the memantinium cation assume typical chair conformations, which is comparable with that found in related structures (Zahid et al., 2009). The Clcounter-anion links with the memantinium cation via N-H···Cl hydrogen bonding (Fig. 1). The lattice water molecules are located on the channels formed by memantininum cations and Clanions (Fig. 2). The O atom of lattice water molecule is located at the threefold rotation axis, and its two H atoms are symmetrically distributed over six sites and linked to Clanions via O-H···Cl hydrogen bonding (Table 1).

Experimental
The crude product is supplied by Zhejiang Apeloa Pharmaceutical Co.,LTD. It was recrystallized from ethanol solution, giving colorless crystals of (1) suitable for X-ray diffraction.

Refinement
Site occupancy factor of the water O1 atom was refined to 0.093 and fixed as 0.1 at the final cycles of refinement. The two H atoms of the water molecule were placed at calculated positions (Nardelli, 1999), and refined as riding in as-found relative positions with U iso (H) = 1.5U eq (O). Other H atoms were placed in calculated positions with C-H = 0.96-0.98 Å and N-H = 0.89 Å, and included in the refinement in riding model, with U iso (H) = 1.2U eq (C) and 1.5U eq (N).  (3,5-dimethyl-1-adamantyl)ammonium chloride 0.1-hydrate

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.