6,6′-Dimethyl-2,2′-[oxalylbis(azanediyl)]dipyridinium dichloride acetonitrile solvate

In the crystal structure of the title compound, C14H16N4O2 2+·2Cl−·CH3CN, weak intermolecular N—H⋯Cl hydrogen bonds are found between the H atoms bound to the pyridine and amine N atoms and the chloride anions. The asymmetric unit consits of one half cationic molecule which is located on a centre of inversion, one chloride anion in a general position and one half acetonitrile molecule which is located on a twofold axis. Because of symmetry, the C—H hydrogens of the acetonitrile solvent molecule are disordered over two orientations.

In the crystal structure of the title compound, C 14 H 16 N 4 O 2 2+ Á-2Cl À ÁCH 3 CN, weak intermolecular N-HÁ Á ÁCl hydrogen bonds are found between the H atoms bound to the pyridine and amine N atoms and the chloride anions. The asymmetric unit consits of one half cationic molecule which is located on a centre of inversion, one chloride anion in a general position and one half acetonitrile molecule which is located on a twofold axis. Because of symmetry, the C-H hydrogens of the acetonitrile solvent molecule are disordered over two orientations.

Structure Reports Online
In the crystal structure the cationic molecules are almost planar and the O atoms are trans-oriented (Fig. 1). The N,N'-Bis(6-methyl-2-pyridinium)oxamide cations and the chloride anions are connected by weak intermolecular N-H···Cl hydrogen bonding (Tab. 1).
Coloress plate crystals of the title compound suitable for X-ray crystallography were obtained by slow evaporization of the solvent from a solution of the precipitate in CH 3 CN.

Refinement
All the hydrogen atoms were placed into idealized positions (methyl H atoms allowed to rotate but not to tip) and constrained by the riding atom approximation with C-H = 0.93 -0.96 Å, N-H = 0.86 Å and U iso (H) = 1.2 U eq (C, N) (1.5 for methyl H atoms). Fig. 1. Crystal structure of the title compound with labeling and displacement ellipsoids drawn at the 30% probability level. Symmetry code: i = -x + 1,-y + 2,-z + 1. Disordering is shown as full and open bonds. as large as those based on F, and R-factors based on ALL data will be even larger.

Figures
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 supplementary materials sup-3 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 > 2sigma(F 2 ) is used only for calculating R-factors(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.
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )