5,6-Dihydroxy-1,10-phenanthrolin-1-ium chloride dihydrate

The title compound, C12H9N2O2 +·Cl−·2H2O, exhibits a layered structure which is stabilized by intermolecular O—H⋯O, O—H⋯Cl− and N+—H⋯Cl− hydrogen bonds, and π–π interactions (centroid–centroid distances = 3.654 and 3.583 Å). The distances between the molecules are 3.371 and 3.294 Å.

The structure of the title compound is shown in Fig. 1. It exhibits a layered structure which is stabilized by inter-molecular O-H···O, O-H···Cl -, N + -H···Clhydrogen bonds, detailed in Fig. 2 and Table 1, as well as π-π interactions and C-H···O, C-H···Clinteractions. With Clas the connecting point, it occurs two different shape parallelograms made up of O and Cl -. The dihedral angle between the two planes, which possess different shapes, is 78.67°. The distances between the layers, which belong to offset face to face, are 3.371 Å and 3.294 Å, reflecting π-π interactions.
Experimental 1,10-phenanthroline-5,6-dione (300 mg, 1.53 mmol) was dissolved in a mixed solution of 10 ml CH 2 Cl 2 and 30 ml EtOH when heating with stirring. When all of the compound dissolved, picoloylhydrazide (200 mg, 1.46 mmol) was added and refluxed 8hrs. Then HCl(aq) was added until the pH was 6. Red crystals of the title compound were obtained by slow evaporation of solvent at room temperature. Analysis: Found C 50.45, H 4.82, N 9.71%, calc. for C 12 H 13 ClN 2 O 4 , C 50.63, H 4.60, N 9.84%.

Refinement
The positions of the O1-, O2-and N2-bound H atoms were placed at fixed positions and refined accord to the riding model.
O3-and O4-bound H atoms were located in a difference Fourier map and refined freely. The C-bound H atoms were included in the riding model approximation with C-H = 0.93 Å and U iso of each H atom = 1.2U eq (C). Fig. 1

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.