Bis(2-amino-3-nitro­pyridinium) dihydrogen­diphosphate

Samah Toumi Akriche; Mohamed Rzaigui; Zeid Abdellah Elothman; Refaat Mohamed Mahfouz

doi:10.1107/S1600536810000942

. 2010 Jan 16;66(Pt 2):o358. doi: 10.1107/S1600536810000942

Bis(2-amino-3-nitropyridinium) dihydrogendiphosphate

Samah Toumi Akriche ^a,^*, Mohamed Rzaigui ^a, Zeid Abdellah Elothman ^b, Refaat Mohamed Mahfouz ^b

PMCID: PMC2979822 PMID: 21579783

Abstract

The structure of the title compound, 2C₅H₆N₃O₂ ⁺·H₂P₂O₇ ²⁻, contains infinite (H₂P₂O₇ ²⁻)_n layers stacked perpendicular to the a axis. The 2-amino-3-nitropyridinium cations are arranged in pairs and are anchored between these layers, linking them by N—H⋯O and C—H⋯O hydrogen-bonding and electrostatic interactions between anionic and cationic species to form a three-dimensional network.

Related literature

For related structures of 2-amino-3-nitropyridinium, see: Akriche & Rzaigui (2000 ▶, 2009a ▶,b ▶,c ▶); Nicoud et al. (1997 ▶). For bond lengths in related structures, see: Aakeröy et al. (1998 ▶). For related structures of diphosphate anions, see: Akriche & Rzaigui (2005 ▶); Charfi & Jouini (2005 ▶); Brodski et al. (2004 ▶); Mrad et al. (2006 ▶); Soumhi et al. (1998 ▶).

Experimental

Crystal data

2C₅H₆N₃O₂ ⁺·H₂O₇P₂ ²⁻
M _r = 456.21
Orthorhombic,
a = 34.250 (5) Å
b = 5.763 (2) Å
c = 8.991 (3) Å
V = 1774.8 (9) Å³
Z = 4
Mo Kα radiation
μ = 0.32 mm⁻¹
T = 298 K
0.29 × 0.25 × 0.19 mm

Data collection

Enraf–Nonius CAD-4 diffractometer
2726 measured reflections
2724 independent reflections
2279 reflections with I > 2σ(I)
R _int = 0.008
2 standard reflections every 120 min intensity decay: 3%

Refinement

R[F ² > 2σ(F ²)] = 0.033
wR(F ²) = 0.091
S = 1.09
2724 reflections
265 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.53 e Å⁻³
Δρ_min = −0.28 e Å⁻³
Absolute structure: Flack (1983 ▶), 443 Friedel pairs
Flack parameter: −0.15 (11)

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994 ▶); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo, 1995 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶) and DIAMOND (Brandenburg & Putz, 2005 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810000942/dn2529sup1.cif

e-66-0o358-sup1.cif^{(20KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810000942/dn2529Isup2.hkl

e-66-0o358-Isup2.hkl^{(131KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2⋯O5ⁱ	0.82	1.73	2.549 (3)	178
O7—H7⋯O1ⁱⁱ	0.82	1.73	2.537 (3)	166
N1—H1⋯O1	0.86	1.87	2.706 (3)	165
N2—H2A⋯O3	0.86	1.88	2.726 (4)	168
N2—H2B⋯O9	0.86	2.05	2.645 (4)	126
N4—H4⋯O6	0.86	1.72	2.582 (4)	174
N5—H5A⋯O5	0.86	1.95	2.786 (4)	165
N5—H5B⋯O10	0.86	2.07	2.669 (5)	126
N5—H5B⋯O3ⁱⁱⁱ	0.86	2.22	2.843 (4)	130
C2—H2C⋯O7^iv	0.93	2.46	3.280 (4)	147
C3—H3⋯O6^iv	0.93	2.34	3.208 (4)	155
C8—H8⋯O9^v	0.93	2.52	3.097 (4)	120

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) ; (v) .

supplementary crystallographic information

Comment

In the framework of our systematic research using the 2-amino-3-nitropyridine (2 A3NP) molecule, we report here the new non-centrosymetric compound, 2(C₅H₆N₃O₂)⁺, H₂P₂O₇^2- (I) obtained by the interaction of the 2 A3NP molecule and diphosphoric acid.

The asymmetric unit of the title compound is built up from one anion H₂P₂O₇^2- and two (C₅H₆N₃O₂)⁺ cations as shown in Fig. 1.

The dihydrogendiphosphate anions are connected through strong hydrogen bonds characterized by relatively short distances (with distances O2···O5 = 2.549 (3) Å and O7···O1 = 2.537 (3) Å (Table 1)), to form corrugated layers parallel to bc plane at x = 0 and x= 1/2 (Fig. 2). Two crystallographically independent cations coexist in this structure. They are arranged in pairs and anchored onto both adjacent anionic layers via N—H···O and C—H···O hydrogen bonds to keep up the three-dimensionel network cohesion.

As expected, the H₂P₂O₇^2- group with bent configuration shows its standard geometry, the longest bonds length P2–O4 = 1.592 (2) Å and P1–O4 = 1.613 (2) Å, correspond to the bridging oxygen atom, the intermediate ones, P1–O2 = 1.552 (2) Å and P2–O7 = 1.545 (2) Å, correspond to the P–OH bonding and the shortest ones spreading between 1.481 (2) Å and 1.515 (2) Å, correspond to the external oxygen atoms. The average values of the P–O distances and O–P–O angles are 1.536 Å and 109.3°. The P–P distance is 2.898 (1) Å and the P–O–P angle is close to 129.4 (1) °. All these distances and angles are similar to those commonly observed in others diphosphate anions (Akriche & Rzaigui, 2005; Charfi & Jouini, 2005; Brodski, et al., 2004; Mrad, et al., 2006). Despite the limited number of organic cation diphosphates (about twenty seven related structures of diphosphate anions), we can distinguish only one non-centrosymmetric structure (Soumhi, et al., 1998) such as the title compound (I).

In this atomic arrangement, one can distinguish the inter-cation contact C8—H8···O9 (H8···O9 = 2.52 Å) which induces the aggregation of the two independent organic cations in pairs (2 A3NP⁺)₂. This kind of arrangement is also observed in the related structure of 2-amino-3-nitropyridinium hydrogenselenate (Akriche & Rzaigui, 2009b). These pairs are located between the anionic layers to link them by manifesting different interactions (Fig. 2). The geometric features of organic cations are usual and comparable with values of other 2-amino-3-nitropyridinium compounds (Akriche & Rzaigui, 2000; Nicoud et al.,1997; Akriche & Rzaigui, 2009a, 2009b, 2009c). It is worth noticing, the C—NH₂ (1.316 (4) Å) and C—NO₂ (1.440 (4) and 1.454 (5) Å) distances in the 2 A3NP cations are respectively shortened and lengthened with respect to the C—NH₂ (1.337 (4) Å) and C—NO₂ (1.429 (4) Å) observed in the 2-amino-3-nitropyridine molecular crystal (Aakeröy, et al., 1998). All the 2-amino-3-nitropyridinium cations encapsulated in various anionic subnetworks show the same changes in C—NH₂ and C—NO₂ distances, revealing a weak increase of pi bond character in C—NH₂ and a decrease in C—NO₂.

Experimental

Single crystals of the title compound were prepared at room temperature by slow evaporation of a mixture of an aqueous solution (20 ml) of diphosphoric acid (5 mmol) and an ethanolic solution (10 ml) of 2-amino-3-nitropyridine (4 mmol, 354 mg). The diphosphoric acid was produced from Na₄P₂O₇ by using a cation-exchange resin (Amberlite IR 120). The resulting solution was evaporated slowly at room temperature for several days until the formation of good quality of prismatic single crystals.