Bis(2,6-diamino-pyridinium) bis-(hydrogen oxalate) monohydrate.

The asymmetric unit of the title compound, 2C(5)H(8)N(3) (+)·2C(2)HO(4) (-)·H(2)O, contains two crystallographically independent 2,6-diamino-pyridinium cations, a pair of hydrogen oxalate anions and a water mol-ecule. Both 2,6-diamino-pyridinium cations are planar, with maximum deviations of 0.011 (2) and 0.015 (1) Å, and are protonated at the pyridine N atoms. The hydrogen oxalate anions adopt twisted conformations and the dihedral angles between the planes of their carboxyl groups are 31.01 (11) and 63.48 (11)°. In the crystal, the cations, anions and water mol-ecules are linked via O-H⋯O and N-H⋯O hydrogen bonds, forming a three-dimensional network.

Related literature

For applications of 2,6-diamino­pyridine, see: Abu Zuhri & Cox (1989 ▶). For related structures, see; Schwalbe et al. (1987 ▶); Al-Dajani et al. (2009 ▶, 2010 ▶); Aghabozorg et al. (2005 ▶); Büyükgüngör & Odabaşoğlu (2006 ▶); Odabaşoğlu & Büyükgüngör (2006 ▶); Haddad & Al-Far (2003 ▶). For details of oxalic acid, see: Subha Nandhini et al. (2001 ▶); Bahadur et al. (2007 ▶); Athimoolam & Natarajan (2007 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

2C5H8N3 +·2C2HO4 −·H2O

M = 416.36

Monoclinic,

a = 8.1681 (1) Å

b = 34.8396 (4) Å

c = 7.2031 (1) Å

β = 114.573 (1)°

V = 1864.16 (4) Å3

Z = 4

Mo Kα radiation

μ = 0.13 mm−1

T = 296 K

0.29 × 0.27 × 0.15 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer

Absorption correction: multi-scan (SADABS; Bruker, 2009) ▶ T min = 0.964, T max = 0.982

33926 measured reflections

4287 independent reflections

3195 reflections with I > 2σ(I)

R int = 0.037

Refinement

R[F 2 > 2σ(F 2)] = 0.048

wR(F 2) = 0.127

S = 1.03

4287 reflections

318 parameters

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.49 e Å−3

Δρmin = −0.30 e Å−3

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536811004119/yk2001sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811004119/yk2001Isup2.hkl

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

2C5H8N3+·2C2HO4−·H2O	F(000) = 872
Mr = 416.36	Dx = 1.484 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 8066 reflections
a = 8.1681 (1) Å	θ = 2.7–29.6°
b = 34.8396 (4) Å	µ = 0.13 mm−1
c = 7.2031 (1) Å	T = 296 K
β = 114.573 (1)°	Block, brown
V = 1864.16 (4) Å3	0.29 × 0.27 × 0.15 mm
Z = 4

Bruker SMART APEXII CCD area-detector diffractometer	4287 independent reflections
Radiation source: fine-focus sealed tube	3195 reflections with I > 2σ(I)
graphite	Rint = 0.037
φ and ω scans	θmax = 27.5°, θmin = 2.3°
Absorption correction: multi-scan (SADABS; Bruker, 2009)	h = −10→10
Tmin = 0.964, Tmax = 0.982	k = −45→44
33926 measured reflections	l = −9→9

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)] = 0.048	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.127	H atoms treated by a mixture of independent and constrained refinement
S = 1.03	w = 1/[σ2(Fo2) + (0.0544P)2 + 0.6267P] where P = (Fo2 + 2Fc2)/3
4287 reflections	(Δ/σ)max = 0.001
318 parameters	Δρmax = 0.49 e Å−3
0 restraints	Δρmin = −0.30 e Å−3

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s 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 > 2σ(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
O1A	0.4482 (2)	0.61834 (4)	0.9547 (3)	0.0707 (5)
O2A	0.17712 (17)	0.59774 (4)	0.7486 (2)	0.0604 (4)
H2A	0.149 (3)	0.6230 (8)	0.768 (4)	0.086 (8)*
O3A	0.57769 (16)	0.55605 (3)	0.8116 (2)	0.0450 (3)
O4A	0.32307 (17)	0.52706 (3)	0.7723 (2)	0.0508 (3)
N1A	0.24244 (19)	0.73699 (4)	0.8214 (2)	0.0379 (3)
H1NA	0.188 (3)	0.7149 (6)	0.820 (3)	0.055 (6)*
N2A	0.4866 (3)	0.69987 (5)	0.8523 (3)	0.0532 (4)
H3NA	0.591 (3)	0.6973 (7)	0.850 (3)	0.067 (7)*
H2NA	0.431 (3)	0.6779 (7)	0.862 (3)	0.065 (7)*
N3A	−0.0132 (2)	0.76858 (5)	0.7974 (3)	0.0530 (4)
H4NA	−0.063 (3)	0.7457 (7)	0.807 (4)	0.074 (7)*
H5NA	−0.073 (3)	0.7903 (6)	0.783 (3)	0.050 (6)*
C7A	0.3497 (2)	0.59436 (5)	0.8417 (3)	0.0426 (4)
C8A	0.4205 (2)	0.55548 (5)	0.8045 (3)	0.0366 (4)
C2A	0.4143 (2)	0.73481 (5)	0.8371 (3)	0.0395 (4)
C3A	0.5024 (3)	0.76876 (6)	0.8363 (3)	0.0486 (4)
H3A	0.6205	0.7684	0.8493	0.058*
C4A	0.4130 (3)	0.80282 (6)	0.8162 (3)	0.0547 (5)
H4A	0.4714	0.8255	0.8127	0.066*
C5A	0.2398 (3)	0.80454 (5)	0.8011 (3)	0.0516 (5)
H5A	0.1820	0.8280	0.7876	0.062*
C6A	0.1525 (2)	0.77058 (5)	0.8062 (3)	0.0400 (4)
O3B	1.06013 (16)	0.66502 (3)	0.7787 (2)	0.0479 (3)
O4B	0.83371 (18)	0.69483 (4)	0.8123 (2)	0.0584 (4)
O1B	0.7509 (2)	0.61351 (4)	0.5650 (2)	0.0694 (5)
O2B	0.7631 (2)	0.61662 (5)	0.8760 (2)	0.0667 (5)
H2B	0.690 (4)	0.5942 (9)	0.840 (4)	0.104 (9)*
N1B	0.72190 (18)	0.48805 (4)	0.7325 (2)	0.0376 (3)
H1NB	0.671 (3)	0.5096 (6)	0.750 (3)	0.049 (5)*
N2B	0.4688 (2)	0.45485 (5)	0.7030 (3)	0.0493 (4)
H2NB	0.423 (3)	0.4775 (7)	0.731 (3)	0.062 (6)*
H3NB	0.408 (3)	0.4336 (7)	0.672 (3)	0.073 (7)*
N3B	0.9553 (3)	0.52718 (5)	0.7489 (3)	0.0582 (5)
H5NB	1.071 (3)	0.5308 (7)	0.762 (3)	0.069 (7)*
H4NB	0.888 (4)	0.5452 (7)	0.739 (4)	0.076 (8)*
C8B	0.9063 (2)	0.66636 (5)	0.7784 (3)	0.0371 (4)
C7B	0.7974 (2)	0.62902 (5)	0.7277 (3)	0.0376 (4)
C2B	0.6357 (2)	0.45385 (5)	0.7121 (3)	0.0383 (4)
C3B	0.7258 (3)	0.42076 (5)	0.7024 (3)	0.0498 (5)
H3B	0.6709	0.3969	0.6882	0.060*
C4B	0.8978 (3)	0.42379 (6)	0.7143 (3)	0.0535 (5)
H4B	0.9594	0.4015	0.7108	0.064*
C5B	0.9815 (3)	0.45863 (6)	0.7310 (3)	0.0497 (5)
H5B	1.0976	0.4600	0.7379	0.060*
C6B	0.8898 (2)	0.49165 (5)	0.7376 (3)	0.0415 (4)
O1W	0.8207 (2)	0.65644 (5)	0.2651 (3)	0.0634 (4)
H2W	0.798 (4)	0.6437 (8)	0.351 (4)	0.096 (10)*
H1W	0.759 (4)	0.6459 (9)	0.157 (5)	0.098 (10)*

	U11	U22	U33	U12	U13	U23
O1A	0.0486 (9)	0.0399 (8)	0.1120 (13)	−0.0056 (6)	0.0219 (8)	−0.0224 (8)
O2A	0.0372 (8)	0.0412 (8)	0.1012 (11)	0.0008 (6)	0.0271 (7)	−0.0223 (7)
O3A	0.0376 (7)	0.0333 (6)	0.0729 (8)	−0.0022 (5)	0.0317 (6)	−0.0039 (6)
O4A	0.0405 (7)	0.0302 (6)	0.0870 (9)	−0.0055 (5)	0.0319 (7)	−0.0086 (6)
N1A	0.0361 (8)	0.0298 (7)	0.0486 (8)	−0.0047 (6)	0.0185 (6)	0.0009 (6)
N2A	0.0470 (10)	0.0429 (10)	0.0781 (12)	0.0037 (8)	0.0344 (9)	0.0017 (8)
N3A	0.0452 (10)	0.0352 (9)	0.0845 (12)	0.0038 (8)	0.0329 (9)	0.0058 (8)
C7A	0.0373 (10)	0.0314 (9)	0.0640 (11)	−0.0022 (7)	0.0259 (8)	−0.0030 (8)
C8A	0.0339 (9)	0.0300 (8)	0.0489 (9)	−0.0025 (7)	0.0203 (7)	−0.0012 (7)
C2A	0.0387 (9)	0.0389 (9)	0.0416 (8)	−0.0012 (7)	0.0172 (7)	−0.0007 (7)
C3A	0.0376 (10)	0.0504 (11)	0.0600 (11)	−0.0101 (8)	0.0223 (8)	−0.0011 (8)
C4A	0.0553 (12)	0.0384 (10)	0.0720 (13)	−0.0147 (9)	0.0279 (10)	−0.0001 (9)
C5A	0.0525 (12)	0.0306 (9)	0.0719 (12)	−0.0024 (8)	0.0261 (10)	0.0029 (8)
C6A	0.0409 (9)	0.0331 (9)	0.0463 (9)	−0.0012 (7)	0.0186 (7)	0.0014 (7)
O3B	0.0367 (7)	0.0328 (6)	0.0814 (9)	−0.0065 (5)	0.0317 (6)	−0.0092 (6)
O4B	0.0447 (8)	0.0325 (7)	0.1075 (11)	−0.0017 (6)	0.0412 (8)	−0.0090 (7)
O1B	0.0931 (12)	0.0613 (9)	0.0681 (9)	−0.0413 (8)	0.0479 (9)	−0.0255 (7)
O2B	0.0829 (11)	0.0623 (10)	0.0626 (9)	−0.0404 (8)	0.0379 (8)	−0.0107 (7)
N1B	0.0342 (8)	0.0293 (7)	0.0525 (8)	0.0011 (6)	0.0213 (6)	−0.0033 (6)
N2B	0.0404 (9)	0.0338 (8)	0.0799 (11)	−0.0065 (7)	0.0314 (8)	−0.0075 (8)
N3B	0.0431 (10)	0.0469 (10)	0.0936 (14)	−0.0114 (8)	0.0374 (10)	−0.0109 (9)
C8B	0.0321 (9)	0.0299 (8)	0.0500 (9)	−0.0009 (7)	0.0179 (7)	−0.0007 (7)
C7B	0.0289 (8)	0.0316 (8)	0.0542 (10)	−0.0011 (7)	0.0191 (7)	−0.0022 (7)
C2B	0.0387 (9)	0.0327 (9)	0.0454 (9)	−0.0015 (7)	0.0194 (7)	−0.0007 (7)
C3B	0.0538 (12)	0.0287 (9)	0.0701 (12)	0.0037 (8)	0.0288 (10)	0.0008 (8)
C4B	0.0526 (12)	0.0430 (11)	0.0678 (12)	0.0168 (9)	0.0279 (10)	0.0014 (9)
C5B	0.0353 (10)	0.0554 (12)	0.0610 (11)	0.0068 (8)	0.0226 (8)	−0.0024 (9)
C6B	0.0348 (9)	0.0430 (10)	0.0487 (9)	−0.0026 (7)	0.0194 (7)	−0.0052 (7)
O1W	0.0745 (11)	0.0547 (9)	0.0603 (10)	−0.0163 (8)	0.0274 (9)	−0.0031 (8)

O1A—C7A	1.209 (2)	O4B—C8B	1.231 (2)
O2A—C7A	1.290 (2)	O1B—C7B	1.200 (2)
O2A—H2A	0.94 (3)	O2B—C7B	1.286 (2)
O3A—C8A	1.2637 (19)	O2B—H2B	0.95 (3)
O4A—C8A	1.2303 (19)	N1B—C2B	1.360 (2)
N1A—C6A	1.362 (2)	N1B—C6B	1.362 (2)
N1A—C2A	1.362 (2)	N1B—H1NB	0.89 (2)
N1A—H1NA	0.89 (2)	N2B—C2B	1.338 (2)
N2A—C2A	1.337 (2)	N2B—H2NB	0.93 (2)
N2A—H3NA	0.87 (2)	N2B—H3NB	0.87 (3)
N2A—H2NA	0.91 (2)	N3B—C6B	1.338 (2)
N3A—C6A	1.330 (2)	N3B—H5NB	0.92 (3)
N3A—H4NA	0.91 (3)	N3B—H4NB	0.82 (3)
N3A—H5NA	0.88 (2)	C8B—C7B	1.532 (2)
C7A—C8A	1.539 (2)	C2B—C3B	1.385 (2)
C2A—C3A	1.386 (2)	C3B—C4B	1.376 (3)
C3A—C4A	1.369 (3)	C3B—H3B	0.9300
C3A—H3A	0.9300	C4B—C5B	1.374 (3)
C4A—C5A	1.374 (3)	C4B—H4B	0.9300
C4A—H4A	0.9300	C5B—C6B	1.385 (3)
C5A—C6A	1.390 (2)	C5B—H5B	0.9300
C5A—H5A	0.9300	O1W—H2W	0.84 (3)
O3B—C8B	1.2567 (19)	O1W—H1W	0.82 (3)
C7A—O2A—H2A	106.9 (16)	C2B—N1B—C6B	123.62 (15)
C6A—N1A—C2A	123.88 (15)	C2B—N1B—H1NB	120.2 (13)
C6A—N1A—H1NA	119.4 (14)	C6B—N1B—H1NB	116.1 (13)
C2A—N1A—H1NA	116.8 (14)	C2B—N2B—H2NB	120.2 (14)
C2A—N2A—H3NA	119.8 (16)	C2B—N2B—H3NB	117.0 (16)
C2A—N2A—H2NA	123.8 (14)	H2NB—N2B—H3NB	123 (2)
H3NA—N2A—H2NA	116 (2)	C6B—N3B—H5NB	120.1 (15)
C6A—N3A—H4NA	121.2 (16)	C6B—N3B—H4NB	117.6 (19)
C6A—N3A—H5NA	117.9 (13)	H5NB—N3B—H4NB	122 (2)
H4NA—N3A—H5NA	121 (2)	O4B—C8B—O3B	126.38 (15)
O1A—C7A—O2A	124.31 (16)	O4B—C8B—C7B	116.86 (14)
O1A—C7A—C8A	122.17 (16)	O3B—C8B—C7B	116.75 (14)
O2A—C7A—C8A	113.46 (15)	O1B—C7B—O2B	124.77 (16)
O4A—C8A—O3A	125.94 (15)	O1B—C7B—C8B	122.12 (16)
O4A—C8A—C7A	118.73 (14)	O2B—C7B—C8B	113.11 (15)
O3A—C8A—C7A	115.33 (14)	N2B—C2B—N1B	117.00 (15)
N2A—C2A—N1A	117.55 (16)	N2B—C2B—C3B	124.81 (17)
N2A—C2A—C3A	124.36 (17)	N1B—C2B—C3B	118.19 (16)
N1A—C2A—C3A	118.09 (16)	C4B—C3B—C2B	118.91 (17)
C4A—C3A—C2A	119.02 (17)	C4B—C3B—H3B	120.5
C4A—C3A—H3A	120.5	C2B—C3B—H3B	120.5
C2A—C3A—H3A	120.5	C5B—C4B—C3B	122.08 (17)
C3A—C4A—C5A	122.15 (18)	C5B—C4B—H4B	119.0
C3A—C4A—H4A	118.9	C3B—C4B—H4B	119.0
C5A—C4A—H4A	118.9	C4B—C5B—C6B	118.73 (17)
C4A—C5A—C6A	118.93 (18)	C4B—C5B—H5B	120.6
C4A—C5A—H5A	120.5	C6B—C5B—H5B	120.6
C6A—C5A—H5A	120.5	N3B—C6B—N1B	117.38 (17)
N3A—C6A—N1A	117.60 (16)	N3B—C6B—C5B	124.22 (17)
N3A—C6A—C5A	124.52 (17)	N1B—C6B—C5B	118.40 (16)
N1A—C6A—C5A	117.88 (16)	H2W—O1W—H1W	103 (3)
C7B—O2B—H2B	112.3 (18)
O1A—C7A—C8A—O4A	147.14 (19)	O4B—C8B—C7B—O1B	116.2 (2)
O2A—C7A—C8A—O4A	−29.9 (2)	O3B—C8B—C7B—O1B	−62.9 (2)
O1A—C7A—C8A—O3A	−32.5 (3)	O4B—C8B—C7B—O2B	−64.0 (2)
O2A—C7A—C8A—O3A	150.49 (17)	O3B—C8B—C7B—O2B	116.95 (18)
C6A—N1A—C2A—N2A	179.59 (16)	C6B—N1B—C2B—N2B	−177.96 (16)
C6A—N1A—C2A—C3A	−0.4 (2)	C6B—N1B—C2B—C3B	2.1 (3)
N2A—C2A—C3A—C4A	178.82 (19)	N2B—C2B—C3B—C4B	−179.77 (18)
N1A—C2A—C3A—C4A	−1.2 (3)	N1B—C2B—C3B—C4B	0.2 (3)
C2A—C3A—C4A—C5A	1.4 (3)	C2B—C3B—C4B—C5B	−1.4 (3)
C3A—C4A—C5A—C6A	0.0 (3)	C3B—C4B—C5B—C6B	0.5 (3)
C2A—N1A—C6A—N3A	−178.21 (16)	C2B—N1B—C6B—N3B	177.04 (17)
C2A—N1A—C6A—C5A	1.8 (3)	C2B—N1B—C6B—C5B	−3.0 (3)
C4A—C5A—C6A—N3A	178.47 (19)	C4B—C5B—C6B—N3B	−178.40 (19)
C4A—C5A—C6A—N1A	−1.5 (3)	C4B—C5B—C6B—N1B	1.7 (3)

D—H···A	D—H	H···A	D···A	D—H···A
N1A—H1NA···O3Bi	0.89 (2)	1.99 (2)	2.8668 (19)	172.5 (18)
O1W—H1W···O1Aii	0.82 (3)	2.53 (3)	3.219 (3)	142 (3)
O1W—H1W···O2Bii	0.82 (3)	2.28 (3)	2.984 (2)	145 (3)
N2A—H3NA···O4B	0.86 (3)	2.11 (3)	2.972 (3)	173.3 (18)
O2A—H2A···O3Bi	0.94 (3)	1.65 (3)	2.5743 (18)	169 (3)
O2B—H2B···O3A	0.95 (3)	1.58 (3)	2.525 (2)	172 (3)
O1W—H2W···O1B	0.84 (3)	2.03 (3)	2.873 (2)	178 (4)
N2A—H2NA···O1A	0.91 (2)	2.17 (2)	2.984 (2)	150 (2)
N3A—H4NA···O4Bi	0.91 (2)	1.97 (3)	2.879 (2)	176 (2)
N3A—H5NA···O1Wiii	0.88 (2)	2.03 (2)	2.908 (2)	172.3 (18)
N1B—H1NB···O3A	0.89 (2)	1.92 (2)	2.8077 (19)	175.0 (17)
N2B—H2NB···O4A	0.93 (2)	1.98 (2)	2.914 (2)	176.2 (18)
N2B—H3NB···O1Biv	0.87 (2)	2.34 (2)	3.121 (2)	150.8 (18)
N3B—H5NB···O2Av	0.92 (3)	2.50 (2)	3.054 (3)	118.8 (19)
N3B—H5NB···O4Av	0.92 (3)	2.03 (3)	2.938 (3)	168 (2)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1A—H1NA⋯O3Bi	0.89 (2)	1.99 (2)	2.8668 (19)	172.5 (18)
O1W—H1W⋯O1Aii	0.82 (3)	2.53 (3)	3.219 (3)	142 (3)
O1W—H1W⋯O2Bii	0.82 (3)	2.28 (3)	2.984 (2)	145 (3)
N2A—H3NA⋯O4B	0.86 (3)	2.11 (3)	2.972 (3)	173.3 (18)
O2A—H2A⋯O3Bi	0.94 (3)	1.65 (3)	2.5743 (18)	169 (3)
O2B—H2B⋯O3A	0.95 (3)	1.58 (3)	2.525 (2)	172 (3)
O1W—H2W⋯O1B	0.84 (3)	2.03 (3)	2.873 (2)	178 (4)
N2A—H2NA⋯O1A	0.91 (2)	2.17 (2)	2.984 (2)	150 (2)
N3A—H4NA⋯O4Bi	0.91 (2)	1.97 (3)	2.879 (2)	176 (2)
N3A—H5NA⋯O1Wiii	0.88 (2)	2.03 (2)	2.908 (2)	172.3 (18)
N1B—H1NB⋯O3A	0.89 (2)	1.92 (2)	2.8077 (19)	175.0 (17)
N2B—H2NB⋯O4A	0.93 (2)	1.98 (2)	2.914 (2)	176.2 (18)
N2B—H3NB⋯O1Biv	0.87 (2)	2.34 (2)	3.121 (2)	150.8 (18)
N3B—H5NB⋯O2Av	0.92 (3)	2.50 (2)	3.054 (3)	118.8 (19)
N3B—H5NB⋯O4Av	0.92 (3)	2.03 (3)	2.938 (3)	168 (2)

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