2-Amino-5-nitro-pyridinium hydrogen oxalate.

In the cation of the title mol-ecular salt, C5H6N3O2 (+)·C2HO4 (-), the dihedral angle between the aromatic ring and the nitro group is 3.5 (3)°; in the anion, the dihedral angle between the CO2 and CO2H planes is 10.5 (2)°. In the crystal, the anions are linked into [100] chains by O-H⋯O hydrogen bonds. The cations cross-link the chains by way of N-H⋯O hydrogen bonds and the structure is consolidated by C-H⋯O inter-actions.

Related literature

For the crystal structures of related pyridine derivatives, see: Babu et al. (2014 ▶); Anderson et al. (2005 ▶); Karle et al. (2003 ▶). For simple organic–inorganic salts containing strong inter­molecular hydrogen bonds, see: Fu et al. (2011 ▶); Sethuram et al. (2013a ▶,b ▶); Shihabuddeen Syed et al. (2013 ▶); Showrilu et al. (2013 ▶); Huq et al. (2013 ▶). For the structure of oxalic acid, see: Derissen & Smith (1974 ▶). For graph-set analysis, see: Bernstein et al.(1995 ▶).

Experimental

Crystal data

C5H6N3O2 +·C2HO4 −

M = 229.16

Triclinic,

a = 5.5609 (2) Å

b = 9.2012 (4) Å

c = 9.2305 (4) Å

α = 90.245 (2)°

β = 98.500 (2)°

γ = 100.038 (2)°

V = 459.74 (3) Å3

Z = 2

Mo Kα radiation

μ = 0.15 mm−1

T = 293 K

0.35 × 0.30 × 0.30 mm

Data collection

Bruker Kappa APEXII CCD diffractometer

Absorption correction: multi-scan (SADABS; Sheldrick, 2004 ▶) T min = 0.950, T max = 0.957

10142 measured reflections

1615 independent reflections

1417 reflections with I > 2σ(I)

R int = 0.020

Refinement

R[F 2 > 2σ(F 2)] = 0.039

wR(F 2) = 0.110

S = 1.07

1615 reflections

153 parameters

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.28 e Å−3

Δρmin = −0.32 e Å−3

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: APEX2 and SAINT (Bruker, 2004 ▶); data reduction: SAINT and XPREP (Bruker, 2004 ▶); 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, 2012 ▶) and Mercury (Macrae et al., 2008 ▶); software used to prepare material for publication: WinGX (Farrugia, 2012 ▶) and PLATON (Spek, 2009 ▶).

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S160053681400525X/jj2183sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S160053681400525X/jj2183Isup2.hkl

Click here for additional data file.

Supporting information file. DOI: 10.1107/S160053681400525X/jj2183Isup3.cml

CCDC reference: 990527

Additional supporting information: crystallographic information; 3D view; checkCIF report

C5H6N3O2+·C2HO4−	Z = 2
Mr = 229.16	F(000) = 236
Triclinic, P1	Dx = 1.655 Mg m−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 5.5609 (2) Å	Cell parameters from 2794 reflections
b = 9.2012 (4) Å	θ = 2.4–31.1°
c = 9.2305 (4) Å	µ = 0.15 mm−1
α = 90.245 (2)°	T = 293 K
β = 98.500 (2)°	Block, colourless
γ = 100.038 (2)°	0.35 × 0.30 × 0.30 mm
V = 459.74 (3) Å3

Bruker Kappa APEXII CCD diffractometer	1615 independent reflections
Radiation source: fine-focus sealed tube	1417 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.020
Detector resolution: 0.1000 pixels mm-1	θmax = 25.0°, θmin = 2.2°
ω and φ scans	h = −6→6
Absorption correction: multi-scan (SADABS; Sheldrick, 2004)	k = −10→10
Tmin = 0.950, Tmax = 0.957	l = −10→10
10142 measured reflections

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.039	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.110	H atoms treated by a mixture of independent and constrained refinement
S = 1.07	w = 1/[σ2(Fo2) + (0.0559P)2 + 0.2329P] where P = (Fo2 + 2Fc2)/3
1615 reflections	(Δ/σ)max < 0.001
153 parameters	Δρmax = 0.28 e Å−3
0 restraints	Δρmin = −0.32 e Å−3

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 F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > 2sigma(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

	x	y	z	Uiso*/Ueq
C1	0.3486 (3)	0.30577 (19)	0.87248 (18)	0.0302 (4)
C2	0.5136 (3)	0.2468 (2)	0.97783 (19)	0.0361 (4)
H2	0.5206	0.2695	1.0768	0.043*
C3	0.6606 (3)	0.1580 (2)	0.9356 (2)	0.0380 (4)
H3	0.7711	0.1201	1.0046	0.046*
C4	0.6446 (3)	0.12349 (19)	0.78639 (19)	0.0338 (4)
C5	0.4879 (3)	0.18053 (19)	0.68547 (19)	0.0332 (4)
H5	0.4796	0.1582	0.5863	0.040*
C6	0.8206 (3)	0.61691 (18)	0.66445 (17)	0.0270 (4)
C7	1.0607 (3)	0.64305 (19)	0.59536 (17)	0.0269 (4)
N1	0.3441 (3)	0.26987 (16)	0.72996 (15)	0.0323 (4)
H1	0.2451	0.3057	0.6649	0.039*
N2	0.2009 (3)	0.39211 (19)	0.90933 (19)	0.0408 (4)
N3	0.7996 (3)	0.02858 (19)	0.73614 (19)	0.0450 (4)
O1	0.7803 (3)	−0.0001 (2)	0.60645 (19)	0.0674 (5)
O2	0.9490 (4)	−0.0148 (3)	0.8270 (2)	0.0882 (7)
O3	0.8197 (2)	0.56345 (16)	0.78510 (13)	0.0410 (4)
O4	0.6388 (2)	0.65291 (16)	0.58166 (14)	0.0409 (4)
H4	0.5159	0.6372	0.6226	0.061*
O5	1.2521 (2)	0.62615 (16)	0.68401 (13)	0.0395 (4)
O6	1.0537 (2)	0.67353 (14)	0.46624 (12)	0.0342 (3)
H2A	0.114 (5)	0.439 (3)	0.842 (3)	0.060 (7)*
H2B	0.208 (4)	0.407 (2)	1.005 (3)	0.051 (6)*

	U11	U22	U33	U12	U13	U23
C1	0.0316 (9)	0.0336 (9)	0.0242 (8)	0.0042 (7)	0.0024 (7)	0.0058 (7)
C2	0.0424 (10)	0.0428 (10)	0.0217 (8)	0.0085 (8)	−0.0013 (7)	0.0051 (7)
C3	0.0379 (10)	0.0426 (10)	0.0313 (9)	0.0111 (8)	−0.0070 (7)	0.0093 (8)
C4	0.0324 (9)	0.0333 (9)	0.0351 (10)	0.0082 (7)	0.0002 (7)	0.0039 (7)
C5	0.0387 (10)	0.0347 (9)	0.0253 (9)	0.0074 (7)	0.0010 (7)	0.0015 (7)
C6	0.0212 (8)	0.0392 (9)	0.0216 (8)	0.0085 (7)	0.0027 (6)	0.0034 (6)
C7	0.0205 (8)	0.0390 (9)	0.0221 (8)	0.0082 (6)	0.0022 (6)	0.0029 (6)
N1	0.0344 (8)	0.0391 (8)	0.0231 (7)	0.0118 (6)	−0.0027 (6)	0.0064 (6)
N2	0.0464 (10)	0.0537 (10)	0.0275 (9)	0.0224 (8)	0.0064 (7)	0.0078 (7)
N3	0.0458 (10)	0.0423 (9)	0.0481 (11)	0.0169 (8)	−0.0003 (8)	0.0007 (7)
O1	0.0832 (12)	0.0683 (11)	0.0567 (10)	0.0355 (9)	0.0044 (9)	−0.0148 (8)
O2	0.0942 (14)	0.1202 (17)	0.0668 (12)	0.0807 (14)	−0.0069 (10)	0.0069 (11)
O3	0.0313 (7)	0.0720 (9)	0.0249 (7)	0.0190 (6)	0.0090 (5)	0.0143 (6)
O4	0.0193 (6)	0.0712 (9)	0.0359 (7)	0.0150 (6)	0.0074 (5)	0.0221 (6)
O5	0.0192 (6)	0.0751 (10)	0.0257 (6)	0.0139 (6)	0.0014 (5)	0.0102 (6)
O6	0.0257 (6)	0.0560 (8)	0.0234 (6)	0.0122 (5)	0.0054 (5)	0.0099 (5)

C1—N2	1.315 (2)	C6—O3	1.220 (2)
C1—N1	1.351 (2)	C6—O4	1.268 (2)
C1—C2	1.413 (2)	C6—C7	1.545 (2)
C2—C3	1.347 (3)	C7—O6	1.222 (2)
C2—H2	0.9300	C7—O5	1.2759 (19)
C3—C4	1.398 (3)	N1—H1	0.8600
C3—H3	0.9300	N2—H2A	0.89 (3)
C4—C5	1.352 (2)	N2—H2B	0.89 (3)
C4—N3	1.448 (2)	N3—O1	1.210 (2)
C5—N1	1.344 (2)	N3—O2	1.211 (2)
C5—H5	0.9300	O4—H4	0.8200
N2—C1—N1	119.96 (16)	O3—C6—C7	120.04 (14)
N2—C1—C2	122.16 (16)	O4—C6—C7	112.84 (13)
N1—C1—C2	117.88 (16)	O6—C7—O5	126.27 (14)
C3—C2—C1	120.31 (16)	O6—C7—C6	120.06 (14)
C3—C2—H2	119.8	O5—C7—C6	113.64 (13)
C1—C2—H2	119.8	C5—N1—C1	122.79 (14)
C2—C3—C4	118.97 (16)	C5—N1—H1	118.6
C2—C3—H3	120.5	C1—N1—H1	118.6
C4—C3—H3	120.5	C1—N2—H2A	121.5 (16)
C5—C4—C3	120.75 (17)	C1—N2—H2B	115.1 (15)
C5—C4—N3	118.45 (16)	H2A—N2—H2B	123 (2)
C3—C4—N3	120.79 (16)	O1—N3—O2	123.01 (19)
N1—C5—C4	119.29 (16)	O1—N3—C4	119.28 (16)
N1—C5—H5	120.4	O2—N3—C4	117.68 (17)
C4—C5—H5	120.4	C6—O4—H4	109.5
O3—C6—O4	127.10 (15)
N2—C1—C2—C3	179.55 (17)	O3—C6—C7—O5	−10.4 (2)
N1—C1—C2—C3	0.1 (3)	O4—C6—C7—O5	171.21 (16)
C1—C2—C3—C4	−0.9 (3)	C4—C5—N1—C1	−0.1 (3)
C2—C3—C4—C5	1.3 (3)	N2—C1—N1—C5	−179.04 (16)
C2—C3—C4—N3	179.89 (17)	C2—C1—N1—C5	0.4 (3)
C3—C4—C5—N1	−0.8 (3)	C5—C4—N3—O1	−1.9 (3)
N3—C4—C5—N1	−179.43 (16)	C3—C4—N3—O1	179.50 (18)
O3—C6—C7—O6	168.06 (17)	C5—C4—N3—O2	175.9 (2)
O4—C6—C7—O6	−10.3 (2)	C3—C4—N3—O2	−2.7 (3)

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2···O5i	0.93	2.48	3.323 (2)	152
C3—H3···O2ii	0.93	2.37	3.296 (2)	178
C5—H5···O1iii	0.93	2.42	3.186 (2)	140
C5—H5···O4iv	0.93	2.44	2.970 (2)	116
N1—H1···O4iv	0.86	2.47	2.9770 (18)	119
N1—H1···O6iv	0.86	1.94	2.7697 (18)	160
O4—H4···O5v	0.82	1.64	2.4486 (16)	170
N2—H2A···O3v	0.89 (3)	2.16 (3)	2.959 (2)	149 (2)
N2—H2A···O5v	0.89 (3)	2.36 (3)	3.007 (2)	130 (2)
N2—H2B···O3vi	0.89 (3)	1.99 (3)	2.870 (2)	173 (2)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C2—H2⋯O5i	0.93	2.48	3.323 (2)	152
C3—H3⋯O2ii	0.93	2.37	3.296 (2)	178
C5—H5⋯O1iii	0.93	2.42	3.186 (2)	140
C5—H5⋯O4iv	0.93	2.44	2.970 (2)	116
N1—H1⋯O6iv	0.86	1.94	2.7697 (18)	160
O4—H4⋯O5v	0.82	1.64	2.4486 (16)	170
N2—H2A⋯O3v	0.89 (3)	2.16 (3)	2.959 (2)	149 (2)
N2—H2A⋯O5v	0.89 (3)	2.36 (3)	3.007 (2)	130 (2)
N2—H2B⋯O3vi	0.89 (3)	1.99 (3)	2.870 (2)	173 (2)

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