2-Amino-3-nitropyridinium perrhenate

In the title molecular salt, (C5H6N3O2)[ReO4], the cations and tetrahedral anions are linked by trifurcated N—H⋯(O,O,O) and bifurcated N—H⋯(O,O) hydrogen bonds, as well as weak C—H⋯O interactions. This results in alternating corrugated inorganic and organic layers in the crystal.


Experimental
Crystal data (C 5
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: HB5451). in these frameworks appear to be the most exciting since they have been recognized as the steering force responsible for the formation of special networks (Katayev et al., 2006). The oxoanions are good hydrogen bond acceptors, that's why they have been employed in the purification, extraction and detection techniques of dangerous pollutants (Ray et al., 2003;Ray et al., 2002;Rodrigues et al., 2009). The 2-amino-3-nitropyridine molecule has a dual nature because of its donor and acceptor groups. It can be protonated and thus serve as a hydrogen bond donor and electrostatic attractive element and also serve as a hydrogen bond acceptor which is especially useful for the binding of oxoanions. In this paper, we will account on the crystal engineering of 2-amino-3-nitropyridininium perrhenate, (C 5 H 6 N 3 O 2 ) + , ReO 4 -(I).
The atomic arrangement of this salt is an organized dispersion of oganic cations and inorganic anions which form alternate corrugated layers (Fig. 2). This projection shows too the extensive network of H-bonds, N-H···O and C-H···O between cation and anion and C-H···O between cations (Table 1). These interactions constitute a key factor as well as electrostatic interaction in the stabilization of this structure. The nitropyridinium cations form chains running parallel to the [101/2] direction. The C-H···O interactions have the same H-bonds geometric parameters as the N-H···O ones which may also consolidate the cohesion of this structure. The neighbour nitropyridinium cations, are linked to form one-dimensional chains via C3-H3···O5 H-bonds (see Table 1 for symmetry codes) with C···O distance of 2.44 Å. Such chains of 2-amino-3-nitropyridinium are also observed in the related structure of 2 A3NPClO4 (Toumi Akriche et al., 2010). In this structure, the (C 5 H 6 N 3 O 2 ) +n chains connect the discrete ReO 4 anions through N-H···O and C-H···O hydrogen bonds in all directions to develop a three-dimensional network. It's worth noticing that the particular behaviour of hydrogen of nitrogen atoms which establish bi-and trifurcated H-bonds, that well explains the weak values of the corresponding angles spreading between 123 and 141°.
The ReO 4 anion have an expected but slightly distorted tetrahedral geometry around Re atom with the Re-O bond lengths ranging from 1.665 (7) (Ray et al., 2003;Ray et al., 2002).  (Akriche et al., 2000;Akriche et al., 2009), that well explain the distortion of XO 4 tetrahedra (X = P and Se) in which the P and Se atoms are displaced of 0.114 to 0.065 Å from gravity center of XO 4 . The ReO 4 tetrahedron is thus described by a regular oxygen atoms arrangement with the rhenium atom slightly shifted from gravity center of ReO 4 (0.042 Å).
As expected, the pyridinium ring of 2-amino-3-nitropyridinium cation is nearly planar, with maximum deviation from planarity equal to 0.021 (5) Å. The diedral angle between the planes of the NO 2 group and the pyridinium ring is close to 4.25

Refinement
All H atoms attached to C and N atoms were fixed geometrically and treated as riding, with C-H = 0.93 Å and N-H = 0.86 Å and with U iso (H) = 1.2Ueq(C or N). Fig. 1. A view of (I) with displacement ellipsoids drawn at the 30% probability level. Hydrogen bonds are represented as dashed lines.

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.