Phenazine–naphthalene-1,5-diamine–water (1/1/2)

The asymmetric unit of the title compound, C12H8N2·C10H10N2·2H2O, contains one half-molecule of phenazine, one half-molecule of naphthalene-1,5-diamine and one water molecule. The phenazine and naphthalene-1,5-diamine molecules are located on inversion centers. The water molecules serve as bridges between the naphthalene-1,5-diamine molecules and also between the naphthalene-1,5-diamine and phenazine molecules. The naphthalene-1,5-diamine and water molecules are connected via N—H⋯O and O—H⋯N hydrogen bonds, forming a T4(2) motif. They are arranged into a two-dimensional polymeric structure parallel to (10) in which the water molecule is a single donor and a double acceptor, whereas the amino group is a double donor and a single acceptor in the hydrogen bonding. These two-dimensional assemblies alternate with the layers of phenazine molecules arranged into a herringbone motif. Each phenazine molecule is hydrogen bonded to two water molecules and thus a three-dimensional framework of hydrogen-bonded molecules is generated.

The asymmetric unit of the title compound, C 12 H 8 N 2 Á-C 10 H 10 N 2 Á2H 2 O, contains one half-molecule of phenazine, one half-molecule of naphthalene-1,5-diamine and one water molecule. The phenazine and naphthalene-1,5-diamine molecules are located on inversion centers. The water molecules serve as bridges between the naphthalene-1,5-diamine molecules and also between the naphthalene-1,5-diamine and phenazine molecules. The naphthalene-1,5-diamine and water molecules are connected via N-HÁ Á ÁO and O-HÁ Á ÁN hydrogen bonds, forming a T4(2) motif. They are arranged into a two-dimensional polymeric structure parallel to (101) in which the water molecule is a single donor and a double acceptor, whereas the amino group is a double donor and a single acceptor in the hydrogen bonding. These two-dimensional assemblies alternate with the layers of phenazine molecules arranged into a herringbone motif. Each phenazine molecule is hydrogen bonded to two water molecules and thus a three-dimensional framework of hydrogen-bonded molecules is generated.

Comment
The title compound has been obtained unintentionally during our attempts to co-crystallize phenazine with naphthalene-1,5diamine. Heterocycles like phenazine and quinoxaline are known to form a robust host framework with one-dimensional channels filled with small aromatic guest molecules (Thalladi et al., 2000;Kadzewski & Gdaniec;. Inclusion of water molecules have however a significant impact on arrangement of molecules in these co-crystals (Czapik & Gdaniec, 2008).
Crystal packing of the title compound is shown in Fig. 2. Phenazine and naphthalene-1,5-diamine molecules are situated around inversion centers and are arranged into stacks along [010] by π-π stacking interactions. The molecules of naphthalene-1,5-diamine and water are connected via N-H···O and O-H···N hydrogen bonds that form the T4(2) motif (Table   1, Fig. 3). These hydrogen bonds connect molecules into a two-dimensional polymeric structure parallel to (1 0 -1) in which the water molecule is a single donor and a double acceptor whereas the amino group plays a role a double donor and a single acceptor (Fig. 3). The layers of naphthalene-1,5-diamine and water molecules alternate with the layers of phenazine in which these aromatic molecules show a herringbone arrangement (Fig. 4). The phenazine molecules are hydrogen bonded to two water molecules and thus a three-dimensional framework of hydrogen-bonded molecules is generated (Fig. 2).
The Cambridge Structural Database (Allen, 2002) was searched for the structures containing C-NH 2 groups and water molecules to look for the frequency of the T4(2) motif (Infantes et al., 2003) generated by primary amino groups and water molecules. The search was limited to organic compounds with polymeric and ionic structures excluded and gave only two structures with the CSD refcodes DISNEZ, (Anthony et al., 2007) and MIMWAH01 (Neely et al., 2007). In both cases the donor and acceptor functions of the amino group and water molecule were analogous to those in the title compound.

Refinement
All H atoms were located in electron-density difference maps. C-bonded H atoms were placed at calculated positions, with C-H = 0.93 Å, and were refined as riding on their carrier C atoms, with U ĩso (H) = 1.2U eq (C). The H atoms of the OH and NH groups were freely refined (coordinates and isotropic displacement parameters).
supplementary materials sup-2 Figures   Fig. 1. : The molecular structure of the title compound with displacement ellipsoids shown at the 50% probability level. Hydrogen bonds are shown as dashed lines and only atoms from the asymmetric unit are labelled.