1,10-Phenanthroline–dithiooxamide (2/1)

The asymmetric unit of the title compound, C12H8N2·0.5C2H4N2S2, contains one 1,10-phenanthroline molecule and a half-molecule of dithiooxamide, which lies across a crystallographic inversion center. The 1,10-phenanthroline unit is not strictly planar, with dihedral angles between the central benzene ring and the pyridine rings of 1.42 (10) and 1.40 (10)°. In the crystal structure, two 1,10-phenanthroline molecules are linked together by one dithiooxamide via intermolecular N—H⋯N hydrogen bonds.

The asymmetric unit of the title compound, C 12 H 8 N 2 Á-0.5C 2 H 4 N 2 S 2 , contains one 1,10-phenanthroline molecule and a half-molecule of dithiooxamide, which lies across a crystallographic inversion center. The 1,10-phenanthroline unit is not strictly planar, with dihedral angles between the central benzene ring and the pyridine rings of 1.42 (10) and 1.40 (10) . In the crystal structure, two 1,10-phenanthroline molecules are linked together by one dithiooxamide via intermolecular N-HÁ Á ÁN hydrogen bonds.

Refinement
H3B and H3C were located in a difference Fourier map and refined freely [N-H = 0.82 (2) and 0.85 (2) Å]. The remaining H atoms were positioned geometrically and refined using a riding model with U iso (H) = 1.2 U eq (C) [C-H = 0.93 Å]. In the final difference Fourier map, the highest peak and the deepest hole are 0.77 and 0.60 Å, respectively, from atom S1. Fig. 1. The molecular structure of the title compound, showing 50% probability displacement ellipsoids and the atom-numbering scheme. Atoms with suffix A [S1A, C13A and N3A] were generated by symmetry code -x+2, -y+2, -z+1.

Special details
Experimental. The crystal was placed in the cold stream of an Oxford Cryosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K.
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.