Bis(2,6-diamino­pyridinium) bis­(hydrogen oxalate) monohydrate

Al-Dajani, M.T.M.; Talaat, J.; Shamsuddin, S.; Hemamalini, M.; Fun, H.-K.

doi:10.1107/S1600536811004119

organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 67| Part 3| March 2011| Pages o591-o592

doi:10.1107/S1600536811004119

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Bis(2,6-diaminopyridinium) bis(hydrogen oxalate) monohydrate

Mohammad T. M. Al-Dajani,^a Jamal Talaat,^b Shaharum Shamsuddin,^c ‡ Madhukar Hemamalini ^d and Hoong-Kun Fun ^d ^*§

^aSchool of Pharmaceutical Sciences, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia, ^bVirginia Commonwealth University, Medicinal Chemistry, USA, ^cKampus Kesihatan, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia, and ^dX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia
^*Correspondence e-mail: hkfun@usm.my

(Received 13 January 2011; accepted 2 February 2011; online 9 February 2011)

The asymmetric unit of the title compound, 2C₅H₈N₃⁺·2C₂HO₄⁻·H₂O, contains two crystallographically independent 2,6-diaminopyridinium cations, a pair of hydrogen oxalate anions and a water molecule. Both 2,6-diaminopyridinium 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 molecules 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_r = 416.36
Monoclinic, P 2₁ /c
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[F² > 2σ(F²)] = 0.048
wR(F²) = 0.127
S = 1.03
4287 reflections
318 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.49 e Å⁻³
Δρ_min = −0.30 e Å⁻³

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⋯O1B^iv	0.87 (2)	2.34 (2)	3.121 (2)	150.8 (18)
N3B—H5NB⋯O2A^v	0.92 (3)	2.50 (2)	3.054 (3)	118.8 (19)
N3B—H5NB⋯O4A^v	0.92 (3)	2.03 (3)	2.938 (3)	168 (2)
Symmetry codes: (i) x-1, y, z; (ii) x, y, z-1; (iii) $[x-1, -y+{\script{3\over 2}}, z+{\script{1\over 2}}]$ ; (iv) -x+1, -y+1, -z+1; (v) x+1, y, z.

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 ).

Supporting information

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

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

checkCIF report

Comment top

2,6-Diaminopyridinium and diaminopyridine in general have an important role in the preparation of aromatic azo dyes, the subject of many polarographic investigations (Abu Zuhri & Cox, 1989). The crystal structures of 2,6-diaminopyridine (Schwalbe et al., 1987), tetrakis(2,6-diaminopyridinium) diphthalate 2,6-diaminopyridine (Al-Dajani et al., 2009), 2,6-diaminopyridinium pyridinium-2,6-dicarboxylate (Aghabozorg et al., 2005), 2,6-diaminopyridinium hydrogen fumarate (Büyükgüngör & Odabaşoğlu, 2006), bis(2,6-diaminopyridinium) oxalate dihydrate (Odabaşoğlu & Büyükgüngör, 2006), 2,6-diamino pyridinium bromide monohydrate (Haddad & Al-Far, 2003) and 2,6-diamino pyridinium 2-carboxybenzoate (Al-Dajani et al., 2010) have been reported in the literature. Oxalic acid, in principle, exists in three ionization states, viz. singly charged (semioxalate), doubly charged (oxalate) and neutral (oxalic acid). In order to study some interesting hydrogen bonding interactions, the synthesis and structure of the title compound, (I), is presented here.

The asymmetric unit of the title compound consists of two crystallographically independent 2,6-diaminopyridinium cations (A & B), two hydrogen oxalate anions (A & B) and a water molecule, as shown in Fig. 1. Each 2,6-diaminopyridinium cation is planar, with a maximum deviation of 0.011 (2)Å for atom C6A in cation A and 0.015 (1)Å for atom N1B in cation B. In the cations, protonation at atoms N1A and N1B lead to a slight increase in the C2A—N1A—C6A [123.88 (15)°] and C2B—N1B—C6B [123.62 (15)°] angles compared to those observed in an unprotonated structure (Schwalbe et al., 1987). The oxalic acid molecule exists in a mono-ionized state in the crystals. Similar observations were also found in the crystal structure of glycinium hydrogen oxalate (Subha Nandhini et al., 2001), creatininium hydrogen oxalate monohydrate (Bahadur et al., 2007) and 3-carboxypyridinium hydrogen oxalate (Athimoolam & Natarajan, 2007). Here, the hydrogen oxalate anions adopt twisted conformations and the dihedral angles between planes of their carboxylic groups are 31.01 (11)° and 63.48 (11)° for anions A and B, respectively.

In the crystal structure, the carboxylate groups of each hydrogen oxalate anion interact with the corresponding 2,6-diaminopyridinium cations via a pair of N—H···O hydrogen bonds forming an R₂ ²(8) ring motif (Fig. 1) (Bernstein et al., 1995). The ionic units and water molecules are linked by O—H···O and N—H···O (Table 1) hydrogen bonds to form a three-dimensional network (Fig. 2).

Related literature top

For applications of 2,6-diaminopyridine, see: Abu Zuhri & Cox (1989). For related structures, see; Schwalbe et al. (1987); Al-Dajani et al. (2009); Aghabozorg et al. (2005); Büyükgüngör & Odabaşoğlu (2006); Odabaşoğlu & Büyükgüngör (2006); Haddad & Al-Far (2003); Al-Dajani et al. (2010). 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 top

Oxalic acid dihydrate (0.01 mol, 1.3 g) was dissolved in 50 ml of methanol in a round bottom flask. 2,6-diaminopyridine (0.01mol, 1.1 g) was dissolved in 50 ml of methanol in a flask and then added in small portions to the oxalic acid with stirring. The reaction mixture was left stirring for 3 hours at room temperature. Brown precipitate was formed, filtered, and washed with methanol. Recrystallization of the brown precipitate with water has yielded after 48 hours brown crystals which was washed with methanol and dried at 353 K.

Computing details top

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

Figures top

	Fig. 1. The asymmetric unit of the title compound, showing 30% probability displacement ellipsoids and the atom-numbering scheme.
	Fig. 2. The crystal packing of the title compound (I).

Bis(2,6-diaminopyridinium) bis(hydrogen oxalate) monohydrate top

Crystal data top

2C₅H₈N₃⁺·2C₂HO₄⁻·H₂O	F(000) = 872
M_r = 416.36	D_x = 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

Data collection top

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

Refinement top

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(F_o²) + (0.0544P)² + 0.6267P] where P = (F_o² + 2F_c²)/3
4287 reflections	(Δ/σ)_max = 0.001
318 parameters	Δρ_max = 0.49 e Å⁻³
0 restraints	Δρ_min = −0.30 e Å⁻³

Crystal data top

2C₅H₈N₃⁺·2C₂HO₄⁻·H₂O	V = 1864.16 (4) Å³
M_r = 416.36	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 8.1681 (1) Å	µ = 0.13 mm⁻¹
b = 34.8396 (4) Å	T = 296 K
c = 7.2031 (1) Å	0.29 × 0.27 × 0.15 mm
β = 114.573 (1)°

Data collection top

Bruker SMART APEXII CCD area-detector diffractometer	4287 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2009)	3195 reflections with I > 2σ(I)
T_min = 0.964, T_max = 0.982	R_int = 0.037
33926 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.048	0 restraints
wR(F²) = 0.127	H atoms treated by a mixture of independent and constrained refinement
S = 1.03	Δρ_max = 0.49 e Å⁻³
4287 reflections	Δρ_min = −0.30 e Å⁻³
318 parameters

Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
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)*

Atomic displacement parameters (Å²) top

	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)

Geometric parameters (Å, º) top

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)

Hydrogen-bond geometry (Å, º) top

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···O1B^iv	0.87 (2)	2.34 (2)	3.121 (2)	150.8 (18)
N3B—H5NB···O2A^v	0.92 (3)	2.50 (2)	3.054 (3)	118.8 (19)
N3B—H5NB···O4A^v	0.92 (3)	2.03 (3)	2.938 (3)	168 (2)

Symmetry codes: (i) x−1, y, z; (ii) x, y, z−1; (iii) x−1, −y+3/2, z+1/2; (iv) −x+1, −y+1, −z+1; (v) x+1, y, z.

Experimental details

Crystal data
Chemical formula	2C₅H₈N₃⁺·2C₂HO₄⁻·H₂O
M_r	416.36
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	296
a, b, c (Å)	8.1681 (1), 34.8396 (4), 7.2031 (1)
β (°)	114.573 (1)
V (Å³)	1864.16 (4)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.13
Crystal size (mm)	0.29 × 0.27 × 0.15

Data collection
Diffractometer	Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2009)
T_min, T_max	0.964, 0.982
No. of measured, independent and observed [I > 2σ(I)] reflections	33926, 4287, 3195
R_int	0.037
(sin θ/λ)_max (Å⁻¹)	0.650

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.048, 0.127, 1.03
No. of reflections	4287
No. of parameters	318
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.49, −0.30

Computer programs: APEX2 (Bruker, 2009), SAINT (Bruker, 2009), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top

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···O1B^iv	0.87 (2)	2.34 (2)	3.121 (2)	150.8 (18)
N3B—H5NB···O2A^v	0.92 (3)	2.50 (2)	3.054 (3)	118.8 (19)
N3B—H5NB···O4A^v	0.92 (3)	2.03 (3)	2.938 (3)	168 (2)

Symmetry codes: (i) x−1, y, z; (ii) x, y, z−1; (iii) x−1, −y+3/2, z+1/2; (iv) −x+1, −y+1, −z+1; (v) x+1, y, z.

Footnotes

‡Additional correspondence author, e-mail: shaharum@kb.usm.my.

§Thomson Reuters ResearcherID: A-3561-2009.

Acknowledgements

SS gratefully acknowledges funding from Universiti Sains Malaysia under the University Research Grant (No. 1001/PPSK/815028). HKF and MH thank the Malaysian Government and Universiti Sains Malaysia for the Research University Grant No. 1001/PFIZIK/811160. MH also thanks Universiti Sains Malaysia for a post-doctoral research fellowship.

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