[Oxalylbis(azanediyl)]bis{[amino(2-pyridyl)methylene]ammonium}

The title compound, C14H16N8O2 2+·2ClO4 −, was prepared by reaction of bis[amino(2-pyridyl)methylene]oxalohydrazide with perchloric acid. The molecular symmetry is Ci and thus the asymmetric unit comprises one half-molecule. The dihedral angle between the aromatic ring and the plane of the oxamide group is 70.8 (3)°. The perchlorate anions and the cations are connected by intermolecular N—H⋯O hydrogen bonds.

The title compound, C 14 H 16 N 8 O 2 2+ Á2ClO 4 À , was prepared by reaction of bis[amino(2-pyridyl)methylene]oxalohydrazide with perchloric acid. The molecular symmetry is C i and thus the asymmetric unit comprises one half-molecule. The dihedral angle between the aromatic ring and the plane of the oxamide group is 70.8 (3) . The perchlorate anions and the cations are connected by intermolecular N-HÁ Á ÁO hydrogen bonds.
Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL. In recent years, researchers showed considerable interest in design and synthesis of polynuclear molecule-based magnetic materials, which were prepared by reactions of special organic molecules with transitional metals. (Niel et al., 2008;Xu et al., 2001;Xu et al., 2003); Zhao et al., 2004). Here we report a new compound, [(C 14 H 16 The asymmetric unit of the title compound comprises a half of the molecule (Fig. 1). In the structure of title compound, the dihedral angle between the aromatic ring and the plane of oxamide group is 70.8 °. Perchlorate anions and cations are connected by intermolecular N-H···O hydrogen bonds (Fig. 2, Table 1).

S2. Experimental
All solvents and chemicals were of analytical grade and were used without further purification. Ligand was prepared by similar procedure reported in the literature (Zhao et al., 2004). For the synthesis of title compoud, a solution of ligand (0.1 mmol), HClO 4 (0.1 mmol) in 20 ml methanol was refluxed for 1 h, and then cooled to room temperature and filtered.
Single crystals suitable for X-ray analysis were grown from the methanol solution by slow evaporation at room temperature in air. Anal. Calcd. for C 14 H 16 N 8 O 10 Cl 2 : C, 31.89; H, 3.06; N, 21.25. Found: C, 32.15; H, 3.18; N, 21.20.

S3. Refinement
All hydrogen atoms were geomemetrically positioned (C-H 0.93-0.97 Å, N-H 0.86 Å) and refined as riding, with U iso (H)=1.2 U eq of the parent atom.  The crystal packing of the title compound generated by intermolecular hydrogen bonds. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 0.33 e Å −3 Δρ min = −0.47 e Å −3 Special details Experimental. The structure was solved by direct methods (Bruker, 2000) and successive difference Fourier syntheses. 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. 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 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.