Crystal structure of the co-crystalline adduct 1,3,6,8-tetraazatricyclo[4.4.1.13,8]dodecane (TATD)–4-chloro-3,5-dimethylphenol (1/1)

In the crystal of the title co-crystalline adduct, the 1,3,6,8-tetraazatricyclo[4.4.1.13,8]dodecane (TATD) and 4-chloro-3,5-dimethylphenol are linked by intermolecular O—H⋯N hydrogen bonds and C—H⋯π interactions.

In the crystal of the title co-crystalline adduct, C 8 H 16 N 4 ÁC 8 H 9 ClO, (I), prepared by solid-state reaction, the molecules are linked by intermolecular O-HÁ Á ÁN hydrogen bonds, forming a D motif. The azaadamantane structure in (I) is slightly distorted, with N-CH 2 -CH 2 -N torsion angles of 10.4 (3) and À9.0 (3) . These values differ slightly from the corresponding torsion angles in the free aminal cage (0.0 ) and in related co-crystalline adducts, which are not far from a planar geometry and consistent with a D 2d molecular symmetry in the tetraazatricyclo structure. The structures also differ in that there is a slight elongation of the N-C bond lengths about the N atom that accepts the hydrogen bond in (I) compared with the other N-C bond lengths. In the crystal, the two molecules are not only linked by a classical O-HÁ Á ÁN hydrogen bond but are further connected by weak C-HÁ Á Á interactions, forming a twodimensional supramolecular network parallel to the bc plane.
To a first approximation, the geometric parameters of the title molecule agree well with those reported for similar structures (Rivera et al., 2007;Rivera, Uribe, Rojas et al., 2015) and are within normal ranges (Allen et al., 1987), but compared to the free aminal cage structure (Rivera et al., 2014) which belongs to the D 2d point group, two small differences are noted. The azaadamantane structure in (I) is slightly distorted, with N-CH 2-CH 2 -N torsion angles of 10.4 (3) (N1-C1-C2-N2) and À9.0 (3) (N3-C7-C8-N4). These values differ slightly from the values of the corresponding torsion angles in the free aminal cage (0.0 ; Rivera et al., 2014), and the related co-crystalline adducts [2.4 (7) (Rivera, Uribe, Rojas et al., 2015) and À0.62 (Rivera et al., 2007)] which shows that each N-C-C-N group is not far from a planar geometry and consistent with a D 2d molecular symmetry in the tetraazatricyclo structure. Furthermore, the structures also differ in the slight elongation of the N1-C bond lengths of the nitrogen atom that accepts the hydrogen bond, [1.470 (2) and 1.480 (2) Å ], compared to the the other N-C bond lengths (Table 1).

Supramolecular features
The two different molecules in (I) are connected by a classical O-HÁ Á ÁN hydrogen bond. The crystal packing is further stabilized by weak intermolecular C-HÁ Á Á interactions, linking the molecules into two-dimensional sheets in the bc plane (Table 2 and Fig. 2). Furthermore, there are short NÁ Á ÁCl contacts [N4Á Á ÁCl1 i 3.1680 (15) Å ; symmetry operator: (i) x, Ày, z À 1 2 ] linking the molecules into zigzag chains running along the c-axis direction (Fig. 3).

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 3. All H atoms were located in difference electron-density maps. The hydroxyl H atom was refined freely, while C-bound H atoms were fixed geometrically (C-H = 0.95, 0.98 or 0.99 Å ) and refined using a riding model, with U iso (H) values set at 1.2U eq (1.5 for methyl groups) of the parent atom. The methyl groups were allowed to rotate but not to tip. Packing diagram of the title compound. Only H atoms involved in hydrogen bonding are shown. Hydrogen bonds are drawn as dashed lines.

Figure 3
Partial packing diagram of the title compound, viewed along the b axis.
Only H atoms involved in hydrogen bonding are shown. Hydrogen bonds are drawn as dashed lines and the short ClÁ Á ÁN contacts are shown as dotted lines. Atoms with suffix A are generated by the symmetry operator (x, Ày, z À 1 2 ) and atoms with suffix B are generated by the symmetry operator (x, Ày, z + 1 2 ).  SHELXL2014 (Sheldrick, 2015); molecular graphics: XP in SHELXTL-Plus (Sheldrick, 2008); software used to prepare material for publication: SHELXL2014 (Sheldrick, 2015).

Special details
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.