Melaminium 2,4,6-trihydroxy­benzoate dihydrate

Prior, T.J.; Goch, O.; Kift, R.L.

doi:10.1107/S1600536809031055

organic compounds

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Volume 65| Part 9| September 2009| Page o2133

doi:10.1107/S1600536809031055

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Melaminium 2,4,6-trihydroxybenzoate dihydrate

Timothy J Prior,^a ^* Osman Goch ^a and Rebecca L Kift ^a

^aDepartment of Chemistry, University of Hull, Kingston upon Hull HU6 7RX, England
^*Correspondence e-mail: t.prior@hull.ac.uk

(Received 4 August 2009; accepted 5 August 2009; online 12 August 2009)

In the title compound, C₃H₇N₆⁺·C₇H₅O₅⁻·2H₂O, the melaminium and benzoate ions are approximately planar (r.m.s. deviation of the non-hydrogen atoms is 0.093 Å) and there is a strong C₂²(8) hydrogen-bonding embrace between them. The centre of symmetry generates a second acid–base pair which is bound to the first by a C₂²(8) (N—H⋯N) embrace common between melamine molecules in similar compounds. Further extensive hydrogen bonding assembles the components into a three-dimensional hydrogen-bonded network.

Related literature

For 2,4,6-trihydroxybenzoic acid and some of its compounds, see: Jankowski et al. (2007 ). For compounds of melamine with aromatic acids, see: Zhang & Chen (2005 ); Perpétuo & Janczak (2005 ); Zhang et al. (2004 ); Karle et al. (2003 ); Janczak & Perpétuo (2001 ). For a description of the Cambridge Crystallographic Database, see: Allen (2002 ). For a structure related to the title compound with C—H⋯O interactions with a homomeric C₂²(8) motif, see: Bouvet et al. (2007 ).

Experimental

Crystal data

C₃H₇N₆⁺·C₇H₅O₅⁻·2H₂O
M_r = 332.29
Monoclinic, P 2₁ /n
a = 6.9914 (6) Å
b = 11.7105 (14) Å
c = 17.1784 (14) Å
β = 93.247 (7)°
V = 1404.2 (2) Å³
Z = 4
Mo Kα radiation
μ = 0.13 mm⁻¹
T = 150 K
0.55 × 0.30 × 0.24 mm

Data collection

Stoe IPDS2 diffractometer
Absorption correction: analytical (X-RED; Stoe & Cie, 2002 ) T_min = 0.945, T_max = 0.973
17706 measured reflections
6005 independent reflections
3332 reflections with I > 2σ(I)
R_int = 0.047

Refinement

R[F² > 2σ(F²)] = 0.042
wR(F²) = 0.127
S = 0.85
6005 reflections
272 parameters
31 restraints
All H-atom parameters refined
Δρ_max = 0.46 e Å⁻³
Δρ_min = −0.36 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1W—H1B⋯O2	0.88 (2)	1.96 (2)	2.8015 (15)	160 (2)
O1W—H1A⋯O3ⁱ	0.887 (19)	2.04 (2)	2.8329 (13)	148 (2)
O2W—H2B⋯O5	0.897 (19)	2.01 (2)	2.8835 (16)	166 (2)
O2W—H2A⋯O1Wⁱⁱ	0.906 (19)	1.903 (19)	2.8050 (15)	173 (2)
N1—H1⋯O1	0.908 (16)	1.869 (16)	2.7729 (13)	173.9 (19)
N4—H4A⋯O2	0.942 (17)	1.886 (17)	2.8245 (14)	174 (2)
N4—H4B⋯O5ⁱⁱⁱ	0.890 (14)	2.214 (16)	3.0049 (14)	147.9 (16)
N5—H5A⋯O2W^iv	0.902 (15)	2.145 (17)	2.8319 (15)	132.2 (15)
N5—H5B⋯N2^v	0.917 (15)	2.017 (15)	2.9339 (15)	179.0 (17)
N6—H6A⋯O3^vi	0.902 (15)	2.334 (16)	3.1215 (14)	145.9 (16)
N6—H6B⋯O2W^vii	0.905 (15)	2.013 (16)	2.9096 (15)	170.2 (17)
O3—H3⋯O1	0.928 (19)	1.64 (2)	2.5235 (12)	156 (2)
O4—H4C⋯O1W^viii	0.880 (18)	1.858 (18)	2.7284 (13)	170 (2)
O5—H5⋯O2	0.921 (19)	1.70 (2)	2.5461 (13)	151 (2)
C6—H6⋯O4^ix	0.975 (17)	2.582 (17)	3.5529 (15)	173.9 (15)
Symmetry codes: (i) -x+2, -y+1, -z; (ii) x-1, y, z; (iii) $[-x+{\script{3\over 2}}, y-{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (iv) -x+1, -y+1, -z; (v) -x+2, -y, -z; (vi) $[x+{\script{1\over 2}}, -y+{\script{1\over 2}}, z+{\script{1\over 2}}]$ ; (vii) x+1, y-1, z; (viii) $[x-{\script{1\over 2}}, -y+{\script{3\over 2}}, z-{\script{1\over 2}}]$ ; (ix) -x+1, -y+2, -z.

Data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-AREA; data reduction: X-RED (Stoe & Cie, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997 ); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809031055/zl2230sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809031055/zl2230Isup2.hkl

checkCIF report

Comment top

Melamine (2,4,6-triamino-s-triazine, C₃H₆N₆) has been widely studied for its potential in the formation of extended hydrogen-bonded solids. For example, crystals of melamine with the following aromatic acids have been reported: benzoic acid (Perpétuo & Janczak, 2005); phthalic acid (Janczak & Perpétuo, 2001); terephthalic acid (Zhang et al., 2004, and Zhang & Chen, 2005); mellitic acid (Karle et al., 2003). The structure of 2,4,6-trihydroxybenzoic acid and those of some co-crystals of this acid have been reported previously by Jankowski et al. (2007). Here we report a co-crystal of melamine and 2,4,6-trihydroxybenzoic acid obtained from aqueous solution.

The title compound crystallizes in the centrosymmetric space group P2₁/n with four formula units in the unit cell. The 2,4,6-trihydroxybenzoic acid molecule is deprotonated at the carboxylic acid function. One of the nitrogen atoms of the triazine ring of melamine is protonated. This acid-base pair forms a complementary C₂²(8) embrace illustrated in Figure 1. Details of the hydrogen bonding within this structure are given in Table 1. A second acid-base pair is generated by the inversion centre. This forms a pair of strong hydrogen bonds to the first through the two melaminium ions. This melamine-melamine C₂²(8) embrace is observed in many other compounds involving melamine. This four molecule unit (illustrated in Figure 2) can be thought of as the repeat unit in an infinite chain. These links are held together by weaker, non-classical C—H···O hydrogen bonds between the C6-(H6) and the hydroxyl group (O4) of another acid unit. This is illustrated in Figure 3. The C···O distance here is 3.5529 (15) Å and the H···O distance is 2.5812 (17) Å. A brief review of about 350 structures with a similar C—H···O (aromatic hydroxyl) homomeric C₂²(8) embrace in the Cambridge Structural Database (Allen, 2002) reveals that the distances and geometry displayed here are in good agreement with those previously reported. One similar example is reported by Bouvet et al. (2007).

Infinite chains formed from this repeat unit are arranged in stacks. The vertical separation between chains is 3.3496 (5) Å. These stacks of chains are arranged along the c axis. The chains within adjacent stacks are alternately parallel to the [120] and [120] directions. The angle between chains parallel to [120] and [120] is 33.242 (8) °. A view of part of the structure down the crystallographic c axis is shown in Figure 4. Between these stacks a large number of classical hydrogen bonds are formed. These are reinforced by the presence of the two water molecules. Full details are given in Table 1.

Related literature top

For 2,4,6-trihydroxybenzoic acid and some of its compounds, see: Jankowski et al. (2007). For compounds of melamine with aromatic acids, see: Zhang & Chen (2005); Perpétuo & Janczak (2005); Zhang et al. (2004); Karle et al. (2003); Janczak & Perpétuo (2001). For a description of the Cambridge Crystallographic Database, see: Allen (2002). For a structure related to the title compound with C—H···O interactions with a homomeric C₂²(8) motif, see: Bouvet et al. (2007).

Experimental top

A solution of melamine and 2,4,6-trihydroxybenzoic acid (0.012 mol dm^-3 in each component) was prepared in deionized water. 5 mL portions of this solution were allowed to evaporate at room temperature in air from suitably sized vials. After a period of approximately two weeks, good sized colourless crystals were obtained.

Computing details top

Data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-AREA (Stoe & Cie, 2002); data reduction: X-RED (Stoe & Cie, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. : ORTEP plot of the asymmetric unit of the title compound. Atoms are drawn as 70% thermal ellipsoids. Dashed lines represent hydrogen bonds.
	Fig. 2. : Repeat unit of the chains present in the title compound.
	Fig. 3. : Part of one of the infinite chains is illustrated. The weak dimeric C—H···O (phenol) interaction joining the links is highlighted.
	Fig. 4. : View of the structure down [001]. Stacks of chains running parallel to [120] and [120] are visible.

Melaminium 2,4,6-trihydroxybenzoate dihydrate top

Crystal data top

C₃H₇N₆⁺·C₇H₅O₅⁻·2H₂O	F(000) = 696
M_r = 332.29	D_x = 1.572 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 10461 reflections
a = 6.9914 (6) Å	θ = 3.0–34.7°
b = 11.7105 (14) Å	µ = 0.13 mm⁻¹
c = 17.1784 (14) Å	T = 150 K
β = 93.247 (7)°	Block, colourless
V = 1404.2 (2) Å³	0.55 × 0.30 × 0.24 mm
Z = 4

Data collection top

Stoe IPDS2 diffractometer	6005 independent reflections
Radiation source: fine-focus sealed tube	3332 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.047
Detector resolution: 6.67 pixels mm^-1	θ_max = 34.8°, θ_min = 2.9°
ω scans	h = −11→9
Absorption correction: analytical (X-RED; Stoe & Cie, 2002)	k = −18→16
T_min = 0.945, T_max = 0.973	l = −27→27
17706 measured reflections

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)] = 0.042	Hydrogen site location: difference Fourier map
wR(F²) = 0.127	All H-atom parameters refined
S = 0.85	w = 1/[σ²(F_o²) + (0.0793P)²] where P = (F_o² + 2F_c²)/3
6005 reflections	(Δ/σ)_max < 0.001
272 parameters	Δρ_max = 0.46 e Å⁻³
31 restraints	Δρ_min = −0.36 e Å⁻³

Crystal data top

C₃H₇N₆⁺·C₇H₅O₅⁻·2H₂O	V = 1404.2 (2) Å³
M_r = 332.29	Z = 4
Monoclinic, P2₁/n	Mo Kα radiation
a = 6.9914 (6) Å	µ = 0.13 mm⁻¹
b = 11.7105 (14) Å	T = 150 K
c = 17.1784 (14) Å	0.55 × 0.30 × 0.24 mm
β = 93.247 (7)°

Data collection top

Stoe IPDS2 diffractometer	6005 independent reflections
Absorption correction: analytical (X-RED; Stoe & Cie, 2002)	3332 reflections with I > 2σ(I)
T_min = 0.945, T_max = 0.973	R_int = 0.047
17706 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.042	31 restraints
wR(F²) = 0.127	All H-atom parameters refined
S = 0.85	Δρ_max = 0.46 e Å⁻³
6005 reflections	Δρ_min = −0.36 e Å⁻³
272 parameters

Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'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 > σ(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
C1	0.73313 (18)	0.52661 (10)	0.05113 (6)	0.0196 (2)
C2	0.68970 (18)	0.63258 (9)	0.00699 (6)	0.0183 (2)
C3	0.69836 (18)	0.63594 (10)	−0.07492 (6)	0.0194 (2)
H3	0.776 (3)	0.4883 (18)	−0.0746 (12)	0.056 (6)*
C4	0.65003 (19)	0.73346 (10)	−0.11738 (6)	0.0211 (2)
H4	0.660 (2)	0.7325 (14)	−0.1742 (9)	0.023 (4)*
C5	0.59022 (19)	0.83049 (10)	−0.07820 (6)	0.0210 (2)
C6	0.5819 (2)	0.83144 (10)	0.00264 (6)	0.0216 (2)
H6	0.542 (3)	0.8992 (15)	0.0306 (10)	0.034 (5)*
C7	0.63057 (18)	0.73331 (10)	0.04389 (6)	0.0194 (2)
O1	0.78156 (15)	0.43781 (8)	0.01487 (5)	0.02431 (19)
O2	0.71931 (15)	0.52808 (8)	0.12494 (5)	0.0244 (2)
O3	0.75288 (15)	0.54163 (8)	−0.11399 (5)	0.0253 (2)
O4	0.53417 (16)	0.92717 (8)	−0.11604 (5)	0.0277 (2)
H4C	0.545 (3)	0.9184 (17)	−0.1665 (10)	0.043 (5)*
O5	0.61673 (15)	0.73672 (8)	0.12263 (5)	0.0243 (2)
H5	0.643 (3)	0.6637 (17)	0.1401 (13)	0.057 (6)*
N1	0.85916 (16)	0.24155 (9)	0.10129 (5)	0.01968 (19)
H1	0.826 (3)	0.3064 (15)	0.0749 (11)	0.039 (5)*
C8	0.91589 (18)	0.14661 (10)	0.06277 (6)	0.0194 (2)
N2	0.97775 (16)	0.05353 (8)	0.10108 (5)	0.0199 (2)
C9	0.98111 (18)	0.06016 (10)	0.17934 (6)	0.0191 (2)
N3	0.92138 (17)	0.14924 (9)	0.22141 (5)	0.0222 (2)
C10	0.86211 (19)	0.23957 (10)	0.18066 (6)	0.0205 (2)
N4	0.8030 (2)	0.33205 (10)	0.21642 (6)	0.0274 (2)
H4A	0.766 (3)	0.3971 (16)	0.1869 (11)	0.047 (6)*
H4B	0.801 (3)	0.3291 (15)	0.2681 (9)	0.028 (4)*
N5	0.90875 (19)	0.14847 (10)	−0.01381 (6)	0.0254 (2)
H5A	0.855 (3)	0.2084 (14)	−0.0399 (10)	0.033 (5)*
H5B	0.944 (3)	0.0848 (14)	−0.0407 (10)	0.032 (5)*
N6	1.04817 (18)	−0.02974 (9)	0.21995 (6)	0.0235 (2)
H6A	1.055 (3)	−0.0259 (16)	0.2725 (9)	0.033 (5)*
H6B	1.102 (3)	−0.0896 (15)	0.1960 (10)	0.033 (5)*
O1W	1.03866 (16)	0.57703 (9)	0.22527 (5)	0.0268 (2)
H1A	1.108 (3)	0.5212 (19)	0.2061 (13)	0.059 (7)*
H1B	0.925 (3)	0.573 (2)	0.2010 (14)	0.066 (7)*
O2W	0.22325 (17)	0.76457 (9)	0.16102 (6)	0.0294 (2)
H2A	0.171 (3)	0.7042 (18)	0.1850 (13)	0.059 (7)*
H2B	0.349 (3)	0.753 (2)	0.1578 (14)	0.062 (7)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0214 (6)	0.0183 (5)	0.0188 (4)	0.0010 (4)	−0.0005 (4)	0.0010 (4)
C2	0.0225 (6)	0.0170 (5)	0.0155 (4)	0.0011 (4)	0.0011 (4)	0.0009 (3)
C3	0.0220 (6)	0.0197 (5)	0.0164 (4)	0.0010 (4)	0.0010 (4)	−0.0020 (3)
C4	0.0257 (6)	0.0221 (5)	0.0154 (4)	0.0015 (4)	0.0011 (4)	0.0008 (4)
C5	0.0239 (6)	0.0192 (5)	0.0197 (5)	0.0016 (4)	0.0004 (4)	0.0022 (4)
C6	0.0281 (7)	0.0185 (5)	0.0183 (5)	0.0042 (4)	0.0019 (4)	0.0002 (4)
C7	0.0223 (6)	0.0197 (5)	0.0163 (4)	0.0015 (4)	0.0011 (4)	0.0007 (3)
O1	0.0338 (5)	0.0176 (4)	0.0215 (4)	0.0046 (3)	0.0016 (3)	0.0002 (3)
O2	0.0352 (6)	0.0205 (4)	0.0175 (4)	0.0044 (4)	0.0011 (3)	0.0024 (3)
O3	0.0389 (6)	0.0204 (4)	0.0168 (3)	0.0066 (4)	0.0026 (3)	−0.0019 (3)
O4	0.0423 (6)	0.0218 (4)	0.0193 (4)	0.0088 (4)	0.0020 (4)	0.0050 (3)
O5	0.0386 (6)	0.0197 (4)	0.0147 (3)	0.0064 (4)	0.0027 (3)	0.0006 (3)
N1	0.0254 (5)	0.0174 (4)	0.0163 (4)	0.0029 (4)	0.0014 (3)	0.0018 (3)
C8	0.0213 (6)	0.0197 (5)	0.0172 (4)	0.0006 (4)	0.0013 (4)	0.0007 (3)
N2	0.0251 (6)	0.0185 (4)	0.0161 (4)	0.0024 (4)	0.0012 (3)	0.0006 (3)
C9	0.0218 (6)	0.0179 (5)	0.0176 (4)	−0.0009 (4)	0.0004 (4)	0.0009 (3)
N3	0.0316 (6)	0.0189 (4)	0.0160 (4)	0.0038 (4)	0.0011 (4)	0.0003 (3)
C10	0.0242 (6)	0.0193 (5)	0.0179 (4)	−0.0001 (4)	0.0015 (4)	−0.0005 (4)
N4	0.0430 (7)	0.0214 (5)	0.0179 (4)	0.0079 (5)	0.0024 (4)	0.0000 (3)
N5	0.0363 (7)	0.0228 (5)	0.0170 (4)	0.0078 (4)	0.0014 (4)	0.0012 (3)
N6	0.0340 (7)	0.0186 (4)	0.0179 (4)	0.0042 (4)	0.0007 (4)	0.0024 (3)
O1W	0.0306 (6)	0.0269 (5)	0.0227 (4)	0.0023 (4)	0.0000 (4)	−0.0043 (3)
O2W	0.0324 (6)	0.0274 (5)	0.0286 (4)	0.0063 (4)	0.0024 (4)	0.0053 (4)

Geometric parameters (Å, º) top

C1—O1	1.2680 (14)	N1—H1	0.908 (16)
C1—O2	1.2772 (13)	C8—N5	1.3139 (15)
C1—C2	1.4768 (16)	C8—N2	1.3327 (15)
C2—C7	1.4120 (16)	N2—C9	1.3455 (14)
C2—C3	1.4124 (15)	C9—N6	1.3333 (15)
C3—O3	1.3580 (14)	C9—N3	1.3487 (15)
C3—C4	1.3865 (16)	N3—C10	1.3221 (15)
C4—C5	1.3967 (17)	C10—N4	1.3226 (16)
C4—H4	0.983 (15)	N4—H4A	0.942 (17)
C5—O4	1.3524 (14)	N4—H4B	0.890 (14)
C5—C6	1.3932 (16)	N5—H5A	0.902 (15)
C6—C7	1.3825 (16)	N5—H5B	0.917 (15)
C6—H6	0.975 (17)	N6—H6A	0.902 (15)
C7—O5	1.3622 (13)	N6—H6B	0.905 (15)
O3—H3	0.928 (19)	O1W—H1A	0.887 (19)
O4—H4C	0.880 (18)	O1W—H1B	0.88 (2)
O5—H5	0.921 (19)	O2W—H2A	0.906 (19)
N1—C10	1.3625 (14)	O2W—H2B	0.897 (19)
N1—C8	1.3642 (15)

O1—C1—O2	122.41 (11)	C10—N1—H1	120.3 (12)
O1—C1—C2	119.33 (10)	C8—N1—H1	120.8 (12)
O2—C1—C2	118.26 (10)	N5—C8—N2	120.06 (11)
C7—C2—C3	117.01 (10)	N5—C8—N1	118.46 (11)
C7—C2—C1	121.90 (9)	N2—C8—N1	121.48 (10)
C3—C2—C1	121.05 (10)	C8—N2—C9	115.66 (10)
O3—C3—C4	118.48 (10)	N6—C9—N2	117.57 (11)
O3—C3—C2	119.91 (10)	N6—C9—N3	116.15 (10)
C4—C3—C2	121.60 (10)	N2—C9—N3	126.27 (11)
C3—C4—C5	119.17 (10)	C10—N3—C9	115.62 (9)
C3—C4—H4	119.0 (10)	N3—C10—N4	120.39 (10)
C5—C4—H4	121.8 (10)	N3—C10—N1	122.00 (11)
O4—C5—C6	116.43 (11)	N4—C10—N1	117.60 (11)
O4—C5—C4	122.40 (10)	C10—N4—H4A	119.7 (13)
C6—C5—C4	121.15 (11)	C10—N4—H4B	117.1 (12)
C7—C6—C5	118.77 (11)	H4A—N4—H4B	123.3 (17)
C7—C6—H6	119.4 (11)	C8—N5—H5A	120.1 (12)
C5—C6—H6	121.8 (11)	C8—N5—H5B	119.6 (11)
O5—C7—C6	117.08 (10)	H5A—N5—H5B	119.8 (16)
O5—C7—C2	120.62 (10)	C9—N6—H6A	118.7 (12)
C6—C7—C2	122.29 (10)	C9—N6—H6B	121.1 (12)
C3—O3—H3	103.2 (14)	H6A—N6—H6B	119.5 (17)
C5—O4—H4C	109.7 (13)	H1A—O1W—H1B	106 (2)
C7—O5—H5	105.9 (14)	H2A—O2W—H2B	109 (2)
C10—N1—C8	118.89 (10)

O1—C1—C2—C7	178.44 (12)	C3—C2—C7—O5	179.37 (12)
O2—C1—C2—C7	−1.23 (19)	C1—C2—C7—O5	1.85 (19)
O1—C1—C2—C3	1.01 (19)	C3—C2—C7—C6	0.30 (19)
O2—C1—C2—C3	−178.65 (12)	C1—C2—C7—C6	−177.22 (12)
C7—C2—C3—O3	−179.54 (12)	C10—N1—C8—N5	178.60 (13)
C1—C2—C3—O3	−2.00 (19)	C10—N1—C8—N2	−1.51 (18)
C7—C2—C3—C4	−0.34 (19)	N5—C8—N2—C9	179.55 (12)
C1—C2—C3—C4	177.20 (12)	N1—C8—N2—C9	−0.35 (18)
O3—C3—C4—C5	178.81 (12)	C8—N2—C9—N6	−177.79 (12)
C2—C3—C4—C5	−0.4 (2)	C8—N2—C9—N3	2.79 (19)
C3—C4—C5—O4	−177.51 (13)	N6—C9—N3—C10	177.49 (12)
C3—C4—C5—C6	1.2 (2)	N2—C9—N3—C10	−3.09 (19)
O4—C5—C6—C7	177.54 (12)	C9—N3—C10—N4	−179.08 (13)
C4—C5—C6—C7	−1.3 (2)	C9—N3—C10—N1	0.93 (19)
C5—C6—C7—O5	−178.62 (12)	C8—N1—C10—N3	1.20 (19)
C5—C6—C7—C2	0.5 (2)	C8—N1—C10—N4	−178.79 (12)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H1B···O2	0.88 (2)	1.96 (2)	2.8015 (15)	160 (2)
O1W—H1A···O3ⁱ	0.89 (2)	2.04 (2)	2.8329 (13)	148 (2)
O2W—H2B···O5	0.90 (2)	2.01 (2)	2.8835 (16)	166 (2)
O2W—H2A···O1Wⁱⁱ	0.91 (2)	1.90 (2)	2.8050 (15)	173 (2)
N1—H1···O1	0.91 (2)	1.87 (2)	2.7729 (13)	174 (2)
N4—H4A···O2	0.94 (2)	1.89 (2)	2.8245 (14)	174 (2)
N4—H4B···O5ⁱⁱⁱ	0.89 (1)	2.21 (2)	3.0049 (14)	148 (2)
N5—H5A···O2W^iv	0.90 (2)	2.15 (2)	2.8319 (15)	132 (2)
N5—H5B···N2^v	0.92 (2)	2.02 (2)	2.9339 (15)	179 (2)
N6—H6A···O3^vi	0.90 (2)	2.33 (2)	3.1215 (14)	146 (2)
N6—H6B···O2W^vii	0.91 (2)	2.01 (2)	2.9096 (15)	170 (2)
O3—H3···O1	0.93 (2)	1.64 (2)	2.5235 (12)	156 (2)
O4—H4C···O1W^viii	0.88 (2)	1.86 (2)	2.7284 (13)	170 (2)
O5—H5···O2	0.92 (2)	1.70 (2)	2.5461 (13)	151 (2)
C6—H6···O4^ix	0.98 (2)	2.58 (2)	3.5529 (15)	174 (2)

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

Experimental details

Crystal data
Chemical formula	C₃H₇N₆⁺·C₇H₅O₅⁻·2H₂O
M_r	332.29
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	150
a, b, c (Å)	6.9914 (6), 11.7105 (14), 17.1784 (14)
β (°)	93.247 (7)
V (Å³)	1404.2 (2)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.13
Crystal size (mm)	0.55 × 0.30 × 0.24

Data collection
Diffractometer	Stoe IPDS2 diffractometer
Absorption correction	Analytical (X-RED; Stoe & Cie, 2002)
T_min, T_max	0.945, 0.973
No. of measured, independent and observed [I > 2σ(I)] reflections	17706, 6005, 3332
R_int	0.047
(sin θ/λ)_max (Å⁻¹)	0.803

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.042, 0.127, 0.85
No. of reflections	6005
No. of parameters	272
No. of restraints	31
H-atom treatment	All H-atom parameters refined
Δρ_max, Δρ_min (e Å⁻³)	0.46, −0.36

Computer programs: X-AREA (Stoe & Cie, 2002), X-RED (Stoe & Cie, 2002), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H1B···O2	0.88 (2)	1.96 (2)	2.8015 (15)	160 (2)
O1W—H1A···O3ⁱ	0.887 (19)	2.04 (2)	2.8329 (13)	148 (2)
O2W—H2B···O5	0.897 (19)	2.01 (2)	2.8835 (16)	166 (2)
O2W—H2A···O1Wⁱⁱ	0.906 (19)	1.903 (19)	2.8050 (15)	173 (2)
N1—H1···O1	0.908 (16)	1.869 (16)	2.7729 (13)	173.9 (19)
N4—H4A···O2	0.942 (17)	1.886 (17)	2.8245 (14)	174 (2)
N4—H4B···O5ⁱⁱⁱ	0.890 (14)	2.214 (16)	3.0049 (14)	147.9 (16)
N5—H5A···O2W^iv	0.902 (15)	2.145 (17)	2.8319 (15)	132.2 (15)
N5—H5B···N2^v	0.917 (15)	2.017 (15)	2.9339 (15)	179.0 (17)
N6—H6A···O3^vi	0.902 (15)	2.334 (16)	3.1215 (14)	145.9 (16)
N6—H6B···O2W^vii	0.905 (15)	2.013 (16)	2.9096 (15)	170.2 (17)
O3—H3···O1	0.928 (19)	1.64 (2)	2.5235 (12)	156 (2)
O4—H4C···O1W^viii	0.880 (18)	1.858 (18)	2.7284 (13)	170 (2)
O5—H5···O2	0.921 (19)	1.70 (2)	2.5461 (13)	151 (2)
C6—H6···O4^ix	0.975 (17)	2.582 (17)	3.5529 (15)	173.9 (15)

Acknowledgements

RLK thanks the University of Hull for the award of a studentship.

References

Allen, F. H. (2002). Acta Cryst. B58, 380–388. Web of Science CrossRef CAS IUCr Journals Google Scholar
Bouvet, M., Malezieux, B., Herson, P. & Villain, F. (2007). CrystEngComm, 9, 270–272. Web of Science CSD CrossRef CAS Google Scholar
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565. CrossRef IUCr Journals Google Scholar
Janczak, J. & Perpétuo, G. J. (2001). Acta Cryst. C57, 123–125. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Jankowski, W., Kadzewski, A. & Gdaniec, M. (2007). Pol. J. Chem. 81, 1095–1108. CAS Google Scholar
Karle, I., Gilardi, R. D., Rao, C. C., Muraleedharan, K. M. & Ranganathan, S. (2003). J. Chem. Crystallogr. 33, 727–749. Web of Science CSD CrossRef CAS Google Scholar
Perpétuo, G. J. & Janczak, J. (2005). Acta Cryst. E61, o287–o289. Web of Science CSD CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Stoe & Cie (2002). X-AREA and X-RED. Stoe & Cie, Darmstadt, Germany. Google Scholar
Zhang, X.-L. & Chen, X.-M. (2005). Cryst. Growth Des. 5, 617–622. Web of Science CSD CrossRef CAS Google Scholar
Zhang, J., Kang, Y., Wen, Y.-H., Li, Z.-J., Qin, Y.-Y. & Yao, Y.-G. (2004). Acta Cryst. E60, o462–o463. Web of Science CSD CrossRef IUCr Journals Google Scholar