l-Histidinium dipicrate dihydrate

Sethuram, M.; Rajasekharan, M.V.; Dhandapani, M.; Amirthaganesan, G.; NizamMohideen, M.

doi:10.1107/S1600536813013949

organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 69| Part 6| June 2013| Pages o957-o958

doi:10.1107/S1600536813013949

Open

access

L-Histidinium dipicrate dihydrate

M. Sethuram,^a M. V. Rajasekharan,^b M. Dhandapani,^a G. Amirthaganesan ^a and M. NizamMohideen ^c ^*

^aDepartment of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641 020, Tamil Nadu, India, ^bSchool of Chemistry, University of Hyderabad, Hyderabad 500 046, Andhra Pradesh, India, and ^cDepartment of Physics, The New College (Autonomous), Chennai 600 014, India
^*Correspondence e-mail: mnizam_new@yahoo.in

(Received 13 May 2013; accepted 20 May 2013; online 25 May 2013)

In the title molecular salt, C₆H₁₁N₃O₂²⁺·2C₆H₂N₃O₇⁻·2H₂O, the histidine molecule exists as a histidinium dication, being protonated at the N atom of the imidazole ring. The charges are balanced by two picrate anions and the compound crystallizes as a dihydrate. In the crystal, the components are linked via N—H⋯O and O—H⋯O hydrogen bonds and weak C—H⋯O interactions, forming a three-dimensional supermolecular structure.

Related literature

For the role of hydrogen bonding in the construction of supramolecular structures, see: Braga et al. (2004 ); Harrowfield et al. (1995 ). For picrates of biologically important molecules, see: Harrison et al. (2007 ); Swamy et al. (2007 ); Bibal et al. (2003 ); Olsher et al. (1996 ). For bond angles in related structures, see: Yang et al. (2001 ).

Experimental

Crystal data

C₆H₁₁N₃O₂²⁺·2C₆H₂N₃O₇⁻·2H₂O
M_r = 649.42
Monoclinic, P 2₁
a = 6.6060 (4) Å
b = 25.7003 (13) Å
c = 7.9627 (5) Å
β = 107.532 (7)°
V = 1289.08 (13) Å³
Z = 2
Mo Kα radiation
μ = 0.15 mm⁻¹
T = 293 K
0.20 × 0.15 × 0.10 mm

Data collection

Bruker Kappa APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2004 ) T_min = 0.970, T_max = 0.985
5817 measured reflections
2982 independent reflections
2560 reflections with I > 2σ(I)
R_int = 0.020

Refinement

R[F² > 2σ(F²)] = 0.039
wR(F²) = 0.088
S = 1.09
2982 reflections
439 parameters
7 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.21 e Å⁻³
Δρ_min = −0.18 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1A⋯O10	0.89	2.19	2.909 (3)	138
N1—H1A⋯O12	0.89	2.11	2.841 (4)	139
N1—H1B⋯O18W	0.89	1.85	2.700 (5)	158
N1—H1C⋯O15ⁱ	0.89	2.16	3.007 (4)	159
N2—H2B⋯O10	0.91 (5)	1.86 (5)	2.709 (4)	154 (4)
N2—H2B⋯O16	0.91 (5)	2.49 (4)	3.125 (4)	128 (3)
N3—H3⋯O9ⁱⁱ	0.86	2.56	2.992 (5)	112
N3—H3⋯O14ⁱⁱ	0.86	2.25	3.077 (4)	160
O2—H2⋯O3ⁱⁱⁱ	0.82	1.86	2.657 (3)	165
O17W—H17A⋯O5^iv	0.84 (2)	2.27 (3)	3.082 (4)	162 (9)
O17W—H17B⋯O3	0.84 (2)	2.14 (8)	2.864 (4)	144 (12)
O18W—H18A⋯O17W^v	0.83 (2)	1.83 (2)	2.664 (5)	176 (5)
O18W—H18B⋯O7	0.83 (2)	2.32 (4)	3.005 (5)	140 (6)
C3—H3B⋯O10	0.97	2.59	3.210 (4)	122
C9—H9⋯O8^vi	0.93	2.40	3.177 (4)	141
C17—H17⋯O11^iv	0.93	2.36	3.177 (3)	147
Symmetry codes: (i) x+1, y, z+1; (ii) $[-x+1, y-{\script{1\over 2}}, -z+1]$ ; (iii) $[-x+2, y-{\script{1\over 2}}, -z+2]$ ; (iv) x, y, z-1; (v) $[-x+2, y-{\script{1\over 2}}, -z+1]$ ; (vi) x, y, z+1.

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 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536813013949/su2602sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536813013949/su2602Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536813013949/su2602Isup3.cml

checkCIF report

Comment top

Intermolecular and inter-ionic hydrogen bonding interactions, which are not only the strongest of the noncovalent interactions but also highly directional, play an important role in constructing supramolecular structures (Braga et al., 2004). Picrate is generally used as an accompanying ion in many systems involving extraction and transport of metal ions to improve the extractability (Bibal et al., 2003). Picrate interacts as a monodentate, bidentate and tridentate ligand (Olsher et al., 1996). Furthermore, picrate is a penta-dentate ligand when it coordinates with cation by chelating pairs of oxygen atoms from p-nitro groups of adjacent picrates, and with successive cations linking the array into a two or three-dimensional network (Harrowfield et al., 1995) and picrates of biologically important molecules (Harrison et al., 2007; Swamy et al., 2007). We have prepared a new picrate of L-Histidinium hydrate and its crystal structure is reported herein.

The asymmetric unit of the title compound, Fig. 1, contains an L-histidinium cation, two picrate anions and two water molecules. The histidine molecule exists as an histidinium ion due to the protonation at the N atom of the imidazole ring. The charges are equilibrated by two picrate anions and crystallizes as a dihydrate. The imidazole ring (N2/N3/C4/C5/C6) makes a dihedral angle of 5.0 (2) and 4.9 (2)° with the benzene rings (C7—C12 and C13—C18), respectively, of the picrate anions.

The picrate anions adopt the keto form with C7—O3 and C13—O10 bond distance of 1.261 (4) and 1.249 (4) Å, C7—C8, C7—C12, C13—C14 and C13—C18 bond distance of 1.445 (4), 1.444 (4), 1.451 (4) and 1.450 (4) Å, respectively, which is longer than the other C—C bond lengths (between 1.374 (5) to 1.460 (4) Å) in the benzene ring. The bond angles C12—C7—C8 and C14—C13—C18 is 111.3 (3) and 110.6 (3)°, respectively, which is the case in some picrate complexes, while the corresponding bond angle of picric acid is 116.4 (5)° [Yang et al., 2001]. In the picrate anion the depronated phenolate oxygen atom deviates slightly from the plane of the benzene ring (torsion angle O3-C7-C8-C9 = -175.4 (3) ° and O10-C13-C14-C15 = 178.2 (3)°). The twist angles between the benzene rings (C7—C12 and C13—C18) and the ortho nitro groups (N4, N6, N7 and N9) are 41.5 (2), 32.4 (2), 32.2 (2) and 34.8 (2), respectively. The para-positioned nitro groups are twisted by 3.4 (2)° (N5) and 5.8 (2)° (N8), and are most likely influenced by a weak hydrogen bond interaction (O18—H18B···O7). The picrate ions are stacked head-to-tail, presumably as a result of charge-transfer interactions.

In the crystal the cation, the picrate anions and the water molecules of crystallization are involved in N—H···O and O—H···O hydrogen bonds and week C—H···O interactions, to form a three-dimensional supramolecular network (Table 1 and Fig. 2).

Related literature top

For the role of hydrogen bonding in the construction of supramolecular structures, see: Braga et al. (2004); Harrowfield et al. (1995). For picrates of biologically important molecules, see: Harrison et al. (2007); Swamy et al. (2007); Bibal et al. (2003); Olsher et al. (1996). For bond angles in related structures, see: Yang et al. (2001).

Experimental top

1:2 stoichiometric proportions of analar grades L-histidine and picric acid (E-Merck) were dissolved in a triply distilled water and ethanol mixture and the two solutions were thoroughly mixed together using mechanical stirrer for about three hours. The clear yellow solution obtained was filtered off to get the crude material. The material was re-dissolved in a water-ethanol solvent mixture and kept aside without any mechanical movement for crystal growth in a dust free environment. Bright yellowish crystals that formed in 5 days were collected carefully from the mother liquor. Several re-crystallizations were done to get ultra pure crystals. The yield in the reaction was ca. 60%. Analysis calc. for C₁₈H₁₈N₉O₁₈: C: 33.34, H: 2.79, N: 19.44 %; Found: C: 33.21, H: 3.74, N: 19.60%.

Computing details top

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).

Figures top

	Fig. 1. View of the molecular structure of the title compound, showing the atom labelling. Displacement ellipsoids are drawn at the 30% probability level.
	Fig. 2. A partial view along the a axisof the crystal packing of the title compound. Dashed lines indicate N—H···O and O—H···O hydrogen bonds and weak C—H···O interactions (see Table 1 for details).

L-Histidinium dipicrate dihydrate top

Crystal data top

C₆H₁₁N₃O₂²⁺·2C₆H₂N₃O₇⁻·2H₂O	F(000) = 668
M_r = 649.42	D_x = 1.673 Mg m⁻³
Monoclinic, P2₁	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2yb	Cell parameters from 5817 reflections
a = 6.6060 (4) Å	θ = 2.4–31.1°
b = 25.7003 (13) Å	µ = 0.15 mm⁻¹
c = 7.9627 (5) Å	T = 293 K
β = 107.532 (7)°	Square, yellow
V = 1289.08 (13) Å³	0.20 × 0.15 × 0.10 mm
Z = 2

Data collection top

Bruker Kappa APEXII CCD diffractometer	2982 independent reflections
Radiation source: fine-focus sealed tube	2560 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.020
ω and ϕ scans	θ_max = 28.9°, θ_min = 2.8°
Absorption correction: multi-scan (SADABS; Sheldrick, 2004)	h = −8→8
T_min = 0.970, T_max = 0.985	k = −26→34
5817 measured reflections	l = −10→9

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.039	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.088	w = 1/[σ²(F_o²) + (0.0341P)² + 0.2411P] where P = (F_o² + 2F_c²)/3
S = 1.09	(Δ/σ)_max < 0.001
2982 reflections	Δρ_max = 0.21 e Å⁻³
439 parameters	Δρ_min = −0.18 e Å⁻³
7 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0095 (12)

Crystal data top

C₆H₁₁N₃O₂²⁺·2C₆H₂N₃O₇⁻·2H₂O	V = 1289.08 (13) Å³
M_r = 649.42	Z = 2
Monoclinic, P2₁	Mo Kα radiation
a = 6.6060 (4) Å	µ = 0.15 mm⁻¹
b = 25.7003 (13) Å	T = 293 K
c = 7.9627 (5) Å	0.20 × 0.15 × 0.10 mm
β = 107.532 (7)°

Data collection top

Bruker Kappa APEXII CCD diffractometer	2982 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 2004)	2560 reflections with I > 2σ(I)
T_min = 0.970, T_max = 0.985	R_int = 0.020
5817 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.039	7 restraints
wR(F²) = 0.088	H atoms treated by a mixture of independent and constrained refinement
S = 1.09	Δρ_max = 0.21 e Å⁻³
2982 reflections	Δρ_min = −0.18 e Å⁻³
439 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
O1	1.1170 (5)	−0.00275 (12)	1.2736 (5)	0.0774 (11)
O2	0.8469 (5)	−0.04330 (11)	1.3342 (4)	0.0566 (8)
H2	0.9346	−0.0664	1.3719	0.085*
O3	0.9237 (4)	0.37442 (9)	0.5194 (3)	0.0366 (6)
O4	1.1711 (5)	0.33930 (12)	1.0182 (3)	0.0618 (9)
O5	0.9113 (6)	0.38681 (13)	0.8677 (4)	0.0659 (9)
O6	1.0105 (5)	0.15561 (11)	0.8787 (3)	0.0527 (7)
O7	0.9511 (5)	0.13208 (10)	0.6075 (3)	0.0507 (7)
O8	0.9119 (4)	0.26246 (10)	0.1693 (3)	0.0456 (6)
O9	0.7415 (5)	0.33288 (10)	0.1914 (3)	0.0489 (7)
O10	0.5060 (4)	0.11319 (9)	0.8159 (3)	0.0379 (6)
O11	0.4555 (4)	0.23048 (10)	1.1305 (3)	0.0443 (6)
O12	0.6326 (5)	0.16004 (10)	1.1346 (3)	0.0505 (7)
O13	0.4413 (5)	0.35254 (9)	0.6731 (4)	0.0529 (7)
O14	0.3963 (5)	0.32377 (10)	0.4098 (3)	0.0522 (7)
O15	0.2242 (5)	0.14022 (12)	0.3056 (3)	0.0565 (8)
O16	0.4623 (6)	0.09005 (11)	0.4743 (4)	0.0668 (9)
N1	0.8717 (5)	0.07237 (10)	1.0875 (4)	0.0354 (6)
H1A	0.7843	0.0987	1.0431	0.053*
H1B	0.8912	0.0535	1.0000	0.053*
H1C	0.9959	0.0848	1.1535	0.053*
N2	0.4952 (5)	0.00857 (12)	0.7727 (4)	0.0380 (7)
N3	0.4987 (6)	−0.07402 (13)	0.7471 (5)	0.0590 (10)
H3	0.4956	−0.1045	0.7020	0.071*
N4	1.0229 (5)	0.34810 (12)	0.8865 (4)	0.0388 (7)
N5	0.9722 (4)	0.16635 (11)	0.7214 (4)	0.0353 (7)
N6	0.8457 (5)	0.29442 (11)	0.2552 (3)	0.0322 (6)
N7	0.5317 (4)	0.19734 (11)	1.0568 (3)	0.0312 (6)
N8	0.4235 (4)	0.31696 (11)	0.5679 (4)	0.0315 (6)
N9	0.3649 (5)	0.13122 (11)	0.4434 (3)	0.0364 (7)
C1	0.9350 (6)	−0.00520 (14)	1.2718 (5)	0.0423 (9)
C2	0.7771 (6)	0.03902 (13)	1.1981 (4)	0.0344 (7)
C3	0.5503 (5)	0.02145 (14)	1.0983 (4)	0.0365 (8)
H3A	0.4943	0.0022	1.1793	0.044*
H3B	0.4629	0.0522	1.0624	0.044*
C4	0.5280 (5)	−0.01146 (13)	0.9395 (4)	0.0331 (7)
C5	0.4757 (6)	−0.03046 (16)	0.6596 (5)	0.0493 (10)
C6	0.5283 (7)	−0.06396 (16)	0.9212 (5)	0.0504 (10)
C7	0.9258 (5)	0.32737 (12)	0.5650 (4)	0.0256 (6)
C8	0.9775 (5)	0.30948 (13)	0.7450 (4)	0.0283 (7)
C9	0.9939 (5)	0.25863 (13)	0.7963 (4)	0.0275 (7)
H9	1.0308	0.2500	0.9151	0.033*
C10	0.9549 (5)	0.22013 (12)	0.6693 (4)	0.0265 (6)
C11	0.9070 (4)	0.23282 (12)	0.4924 (4)	0.0259 (6)
H11	0.8856	0.2068	0.4077	0.031*
C12	0.8915 (5)	0.28421 (11)	0.4435 (4)	0.0235 (6)
C13	0.4825 (5)	0.15872 (12)	0.7585 (4)	0.0260 (6)
C14	0.5012 (5)	0.20440 (12)	0.8692 (4)	0.0232 (6)
C15	0.4816 (5)	0.25485 (12)	0.8099 (4)	0.0246 (6)
H15	0.4977	0.2825	0.8884	0.030*
C16	0.4375 (5)	0.26384 (12)	0.6310 (4)	0.0237 (6)
C17	0.3974 (4)	0.22294 (12)	0.5116 (4)	0.0247 (6)
H17	0.3562	0.2293	0.3910	0.030*
C18	0.4195 (5)	0.17329 (12)	0.5740 (4)	0.0249 (6)
O17W	1.0107 (7)	0.43238 (13)	0.2418 (5)	0.0724 (10)
O18W	1.0051 (8)	0.03423 (14)	0.8230 (5)	0.0779 (11)
H17A	1.006 (14)	0.415 (3)	0.150 (7)	0.18 (4)*
H17B	1.04 (2)	0.411 (3)	0.325 (9)	0.31 (7)*
H18A	1.001 (9)	0.0022 (8)	0.808 (7)	0.086 (19)*
H18B	0.977 (15)	0.049 (2)	0.726 (5)	0.19 (4)*
H2A	0.763 (6)	0.0623 (16)	1.296 (5)	0.039 (10)*
H6	0.539 (7)	−0.0916 (19)	0.999 (6)	0.064 (13)*
H5	0.455 (7)	−0.029 (2)	0.536 (6)	0.068 (13)*
H2B	0.479 (7)	0.0432 (19)	0.751 (5)	0.053 (12)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0441 (17)	0.047 (2)	0.123 (3)	0.0016 (14)	−0.0029 (17)	0.0338 (19)
O2	0.0723 (19)	0.0389 (16)	0.0567 (16)	0.0113 (15)	0.0166 (14)	0.0245 (13)
O3	0.0544 (15)	0.0211 (12)	0.0300 (11)	−0.0025 (11)	0.0064 (10)	−0.0010 (9)
O4	0.083 (2)	0.0564 (19)	0.0295 (13)	−0.0121 (17)	−0.0084 (13)	−0.0061 (13)
O5	0.096 (2)	0.0489 (19)	0.0517 (16)	0.0160 (18)	0.0213 (15)	−0.0173 (14)
O6	0.0750 (19)	0.0426 (16)	0.0386 (14)	−0.0024 (14)	0.0143 (13)	0.0187 (12)
O7	0.0717 (19)	0.0268 (14)	0.0524 (16)	−0.0034 (14)	0.0168 (13)	0.0001 (13)
O8	0.0684 (17)	0.0436 (16)	0.0298 (12)	−0.0007 (14)	0.0225 (12)	−0.0067 (11)
O9	0.0775 (19)	0.0295 (13)	0.0292 (12)	0.0062 (13)	0.0000 (12)	0.0058 (10)
O10	0.0591 (16)	0.0204 (12)	0.0299 (12)	0.0018 (11)	0.0070 (11)	0.0016 (9)
O11	0.0660 (16)	0.0427 (15)	0.0298 (12)	0.0072 (13)	0.0229 (12)	−0.0033 (11)
O12	0.080 (2)	0.0350 (14)	0.0269 (12)	0.0154 (14)	0.0007 (12)	0.0059 (11)
O13	0.079 (2)	0.0174 (13)	0.0575 (16)	0.0002 (13)	0.0135 (14)	−0.0002 (12)
O14	0.081 (2)	0.0376 (15)	0.0368 (13)	0.0005 (15)	0.0155 (13)	0.0172 (12)
O15	0.0706 (19)	0.0514 (18)	0.0320 (13)	−0.0160 (15)	−0.0078 (12)	−0.0063 (12)
O16	0.112 (3)	0.0364 (17)	0.0446 (16)	0.0147 (18)	0.0118 (17)	−0.0133 (13)
N1	0.0395 (15)	0.0194 (14)	0.0404 (16)	−0.0002 (12)	0.0017 (12)	0.0029 (11)
N2	0.0445 (17)	0.0244 (15)	0.0380 (16)	−0.0015 (14)	0.0019 (13)	−0.0004 (13)
N3	0.082 (3)	0.0247 (17)	0.058 (2)	−0.0058 (18)	0.0021 (18)	−0.0120 (15)
N4	0.0573 (19)	0.0330 (18)	0.0281 (14)	−0.0092 (15)	0.0158 (13)	−0.0041 (12)
N5	0.0356 (15)	0.0281 (16)	0.0416 (16)	−0.0027 (13)	0.0110 (12)	0.0070 (13)
N6	0.0444 (16)	0.0279 (15)	0.0219 (13)	−0.0078 (13)	0.0066 (11)	−0.0031 (11)
N7	0.0428 (16)	0.0261 (15)	0.0220 (13)	−0.0012 (13)	0.0056 (11)	−0.0016 (11)
N8	0.0286 (14)	0.0255 (15)	0.0399 (15)	−0.0017 (12)	0.0096 (11)	0.0060 (12)
N9	0.0547 (18)	0.0253 (15)	0.0290 (14)	−0.0073 (14)	0.0122 (13)	−0.0055 (12)
C1	0.048 (2)	0.0270 (19)	0.0382 (19)	−0.0013 (17)	−0.0072 (16)	0.0034 (15)
C2	0.0470 (19)	0.0246 (17)	0.0274 (15)	0.0004 (15)	0.0048 (14)	0.0022 (13)
C3	0.0412 (18)	0.0329 (18)	0.0341 (17)	0.0030 (16)	0.0097 (14)	0.0045 (14)
C4	0.0338 (16)	0.0230 (16)	0.0377 (17)	−0.0032 (14)	0.0037 (13)	0.0027 (14)
C5	0.058 (2)	0.038 (2)	0.043 (2)	−0.0062 (19)	0.0018 (18)	−0.0087 (18)
C6	0.064 (3)	0.031 (2)	0.045 (2)	−0.0083 (19)	0.0001 (19)	0.0019 (18)
C7	0.0269 (15)	0.0258 (16)	0.0221 (14)	−0.0025 (13)	0.0046 (11)	−0.0039 (12)
C8	0.0311 (16)	0.0290 (17)	0.0248 (15)	−0.0051 (14)	0.0081 (12)	−0.0064 (13)
C9	0.0295 (15)	0.0314 (18)	0.0224 (14)	−0.0003 (14)	0.0090 (12)	0.0034 (13)
C10	0.0251 (14)	0.0234 (16)	0.0313 (15)	−0.0005 (13)	0.0088 (11)	0.0038 (12)
C11	0.0254 (14)	0.0262 (16)	0.0263 (14)	−0.0033 (13)	0.0082 (11)	−0.0041 (12)
C12	0.0288 (15)	0.0187 (14)	0.0213 (14)	−0.0009 (12)	0.0051 (11)	−0.0007 (11)
C13	0.0275 (15)	0.0248 (16)	0.0251 (15)	0.0014 (13)	0.0070 (12)	−0.0005 (13)
C14	0.0267 (14)	0.0246 (16)	0.0176 (14)	0.0022 (13)	0.0057 (11)	0.0006 (11)
C15	0.0256 (14)	0.0233 (15)	0.0239 (14)	0.0018 (13)	0.0057 (11)	−0.0023 (12)
C16	0.0229 (14)	0.0202 (15)	0.0276 (15)	0.0015 (12)	0.0072 (11)	0.0048 (12)
C17	0.0254 (14)	0.0274 (17)	0.0215 (14)	−0.0005 (13)	0.0074 (11)	0.0027 (12)
C18	0.0270 (15)	0.0252 (16)	0.0215 (15)	−0.0004 (13)	0.0058 (12)	−0.0030 (11)
O17W	0.126 (3)	0.0397 (18)	0.0615 (19)	−0.0171 (19)	0.043 (2)	−0.0111 (15)
O18W	0.125 (3)	0.043 (2)	0.085 (3)	0.009 (2)	0.060 (2)	0.0001 (18)

Geometric parameters (Å, º) top

O1—C1	1.199 (5)	N8—C16	1.448 (4)
O2—C1	1.311 (5)	N9—C18	1.468 (4)
O2—H2	0.8200	C1—C2	1.534 (5)
O3—C7	1.261 (4)	C2—C3	1.537 (5)
O4—N4	1.220 (4)	C2—H2A	1.01 (4)
O5—N4	1.220 (4)	C3—C4	1.491 (5)
O6—N5	1.232 (4)	C3—H3A	0.9700
O7—N5	1.242 (4)	C3—H3B	0.9700
O8—N6	1.230 (4)	C4—C6	1.357 (5)
O9—N6	1.224 (4)	C5—H5	0.96 (5)
O10—C13	1.249 (4)	C6—H6	0.93 (5)
O11—N7	1.225 (3)	C7—C12	1.444 (4)
O12—N7	1.224 (4)	C7—C8	1.445 (4)
O13—N8	1.222 (4)	C8—C9	1.363 (5)
O14—N8	1.230 (4)	C9—C10	1.383 (4)
O15—N9	1.228 (4)	C9—H9	0.9300
O16—N9	1.224 (4)	C10—C11	1.387 (4)
N1—C2	1.494 (4)	C11—C12	1.372 (4)
N1—H1A	0.8900	C11—H11	0.9300
N1—H1B	0.8900	C13—C14	1.451 (4)
N1—H1C	0.8900	C13—C18	1.450 (4)
N2—C5	1.328 (5)	C14—C15	1.373 (4)
N2—C4	1.380 (4)	C15—C16	1.385 (4)
N2—H2B	0.91 (5)	C15—H15	0.9300
N3—C5	1.303 (5)	C16—C17	1.388 (4)
N3—C6	1.365 (5)	C17—C18	1.361 (4)
N3—H3	0.8600	C17—H17	0.9300
N4—C8	1.463 (4)	O17W—H17A	0.84 (2)
N5—C10	1.438 (4)	O17W—H17B	0.84 (2)
N6—C12	1.461 (4)	O18W—H18A	0.83 (2)
N7—C14	1.457 (4)	O18W—H18B	0.83 (2)

C1—O2—H2	109.5	C6—C4—N2	105.8 (3)
C2—N1—H1A	109.5	C6—C4—C3	130.7 (3)
C2—N1—H1B	109.5	N2—C4—C3	123.5 (3)
H1A—N1—H1B	109.5	N3—C5—N2	108.3 (4)
C2—N1—H1C	109.5	N3—C5—H5	124 (3)
H1A—N1—H1C	109.5	N2—C5—H5	128 (3)
H1B—N1—H1C	109.5	C4—C6—N3	107.0 (4)
C5—N2—C4	109.0 (3)	C4—C6—H6	134 (3)
C5—N2—H2B	129 (3)	N3—C6—H6	119 (3)
C4—N2—H2B	121 (3)	O3—C7—C12	123.9 (3)
C5—N3—C6	109.8 (3)	O3—C7—C8	124.7 (3)
C5—N3—H3	125.1	C12—C7—C8	111.3 (3)
C6—N3—H3	125.1	C9—C8—C7	125.1 (3)
O5—N4—O4	123.7 (3)	C9—C8—N4	116.1 (3)
O5—N4—C8	118.8 (3)	C7—C8—N4	118.7 (3)
O4—N4—C8	117.5 (3)	C8—C9—C10	119.1 (3)
O6—N5—O7	121.8 (3)	C8—C9—H9	120.4
O7—N5—O7	0.0 (3)	C10—C9—H9	120.4
O6—N5—C10	118.9 (3)	C9—C10—C11	120.7 (3)
O7—N5—C10	119.3 (3)	C9—C10—N5	119.7 (3)
O9—N6—O8	123.9 (3)	C11—C10—N5	119.6 (3)
O9—N6—C12	119.2 (3)	C12—C11—C10	119.3 (3)
O8—N6—C12	116.9 (3)	C12—C11—H11	120.3
O12—N7—O11	122.8 (3)	C10—C11—H11	120.3
O12—N7—C14	120.2 (3)	C11—C12—C7	124.5 (3)
O11—N7—C14	117.0 (3)	C11—C12—N6	116.0 (3)
O13—N8—O14	123.4 (3)	C7—C12—N6	119.4 (3)
O13—N8—C16	119.0 (3)	O10—C13—C14	123.9 (3)
O14—N8—C16	117.6 (3)	O10—C13—C18	125.4 (3)
O16—N9—O15	123.6 (3)	C14—C13—C18	110.6 (3)
O16—N9—C18	119.5 (3)	C15—C14—C13	125.0 (2)
O15—N9—C18	116.9 (3)	C15—C14—N7	116.1 (3)
O1—C1—O2	126.3 (4)	C13—C14—N7	118.8 (3)
O1—C1—C2	121.9 (3)	C14—C15—C16	118.7 (3)
O2—C1—C2	111.7 (3)	C14—C15—H15	120.6
N1—C2—C1	107.1 (3)	C16—C15—H15	120.6
N1—C2—C3	112.3 (3)	C15—C16—C17	121.1 (3)
C1—C2—C3	115.1 (3)	C15—C16—N8	119.1 (3)
N1—C2—H2A	105 (2)	C17—C16—N8	119.8 (3)
C1—C2—H2A	111 (2)	C18—C17—C16	118.8 (3)
C3—C2—H2A	106 (2)	C18—C17—H17	120.6
C4—C3—C2	115.9 (3)	C16—C17—H17	120.6
C4—C3—H3A	108.3	C17—C18—C13	125.4 (3)
C2—C3—H3A	108.3	C17—C18—N9	117.1 (2)
C4—C3—H3B	108.3	C13—C18—N9	117.5 (3)
C2—C3—H3B	108.3	H17A—O17W—H17B	106 (3)
H3A—C3—H3B	107.4	H18A—O18W—H18B	109 (3)

O1—C1—C2—N1	17.5 (5)	C8—C7—C12—C11	−0.3 (4)
O2—C1—C2—N1	−164.4 (3)	O3—C7—C12—N6	−1.7 (5)
O1—C1—C2—C3	143.1 (4)	C8—C7—C12—N6	−177.6 (3)
O2—C1—C2—C3	−38.8 (4)	O9—N6—C12—C11	148.0 (3)
N1—C2—C3—C4	62.2 (4)	O8—N6—C12—C11	−30.3 (4)
C1—C2—C3—C4	−60.7 (4)	O9—N6—C12—C7	−34.5 (4)
C5—N2—C4—C6	0.3 (4)	O8—N6—C12—C7	147.2 (3)
C5—N2—C4—C3	−178.1 (3)	O10—C13—C14—C15	178.2 (3)
C2—C3—C4—C6	92.6 (5)	C18—C13—C14—C15	−5.6 (4)
C2—C3—C4—N2	−89.5 (4)	O10—C13—C14—N7	−5.3 (5)
C6—N3—C5—N2	1.7 (5)	C18—C13—C14—N7	170.9 (2)
C4—N2—C5—N3	−1.2 (5)	O12—N7—C14—C15	−150.2 (3)
N2—C4—C6—N3	0.7 (4)	O11—N7—C14—C15	28.7 (4)
C3—C4—C6—N3	179.0 (4)	O12—N7—C14—C13	33.0 (4)
C5—N3—C6—C4	−1.5 (5)	O11—N7—C14—C13	−148.1 (3)
O3—C7—C8—C9	−175.4 (3)	C13—C14—C15—C16	1.0 (5)
C12—C7—C8—C9	0.4 (4)	N7—C14—C15—C16	−175.5 (2)
O3—C7—C8—N4	2.6 (5)	C14—C15—C16—C17	4.9 (4)
C12—C7—C8—N4	178.4 (3)	C14—C15—C16—N8	−178.0 (3)
O5—N4—C8—C9	−139.3 (3)	O13—N8—C16—C15	−3.4 (4)
O4—N4—C8—C9	40.2 (4)	O14—N8—C16—C15	175.9 (3)
O5—N4—C8—C7	42.6 (5)	O13—N8—C16—C17	173.8 (3)
O4—N4—C8—C7	−138.0 (3)	O14—N8—C16—C17	−6.9 (4)
C7—C8—C9—C10	−1.4 (5)	C15—C16—C17—C18	−5.4 (4)
N4—C8—C9—C10	−179.4 (3)	N8—C16—C17—C18	177.5 (3)
C8—C9—C10—C11	2.2 (4)	C16—C17—C18—C13	0.1 (5)
C8—C9—C10—N5	179.8 (3)	C16—C17—C18—N9	176.9 (3)
O6—N5—C10—C9	3.9 (4)	O10—C13—C18—C17	−178.8 (3)
O7—N5—C10—C9	−175.1 (3)	C14—C13—C18—C17	5.1 (4)
O6—N5—C10—C11	−178.5 (3)	O10—C13—C18—N9	4.4 (5)
O7—N5—C10—C11	2.5 (4)	C14—C13—C18—N9	−171.8 (3)
C9—C10—C11—C12	−2.2 (4)	O16—N9—C18—C17	147.2 (3)
N5—C10—C11—C12	−179.7 (3)	O15—N9—C18—C17	−31.3 (4)
C10—C11—C12—C7	1.2 (5)	O16—N9—C18—C13	−35.7 (4)
C10—C11—C12—N6	178.6 (2)	O15—N9—C18—C13	145.8 (3)
O3—C7—C12—C11	175.6 (3)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O10	0.89	2.19	2.909 (3)	138
N1—H1A···O12	0.89	2.11	2.841 (4)	139
N1—H1B···O18W	0.89	1.85	2.700 (5)	158
N1—H1C···O15ⁱ	0.89	2.16	3.007 (4)	159
N2—H2B···O10	0.91 (5)	1.86 (5)	2.709 (4)	154 (4)
N2—H2B···O16	0.91 (5)	2.49 (4)	3.125 (4)	128 (3)
N3—H3···O9ⁱⁱ	0.86	2.56	2.992 (5)	112
N3—H3···O14ⁱⁱ	0.86	2.25	3.077 (4)	160
O2—H2···O3ⁱⁱⁱ	0.82	1.86	2.657 (3)	165
O17W—H17A···O5^iv	0.84 (2)	2.27 (3)	3.082 (4)	162 (9)
O17W—H17B···O3	0.84 (2)	2.14 (8)	2.864 (4)	144 (12)
O18W—H18A···O17W^v	0.83 (2)	1.83 (2)	2.664 (5)	176 (5)
O18W—H18B···O7	0.83 (2)	2.32 (4)	3.005 (5)	140 (6)
C3—H3B···O10	0.97	2.59	3.210 (4)	122
C9—H9···O8^vi	0.93	2.40	3.177 (4)	141
C17—H17···O11^iv	0.93	2.36	3.177 (3)	147

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

Experimental details

Crystal data
Chemical formula	C₆H₁₁N₃O₂²⁺·2C₆H₂N₃O₇⁻·2H₂O
M_r	649.42
Crystal system, space group	Monoclinic, P2₁
Temperature (K)	293
a, b, c (Å)	6.6060 (4), 25.7003 (13), 7.9627 (5)
β (°)	107.532 (7)
V (Å³)	1289.08 (13)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.15
Crystal size (mm)	0.20 × 0.15 × 0.10

Data collection
Diffractometer	Bruker Kappa APEXII CCD diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 2004)
T_min, T_max	0.970, 0.985
No. of measured, independent and observed [I > 2σ(I)] reflections	5817, 2982, 2560
R_int	0.020
(sin θ/λ)_max (Å⁻¹)	0.680

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.039, 0.088, 1.09
No. of reflections	2982
No. of parameters	439
No. of restraints	7
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.21, −0.18

Computer programs: APEX2 (Bruker, 2004), APEX2 and SAINT (Bruker, 2004), SAINT and XPREP (Bruker, 2004), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 2012) and Mercury (Macrae et al., 2008), WinGX (Farrugia, 2012) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O10	0.89	2.19	2.909 (3)	138
N1—H1A···O12	0.89	2.11	2.841 (4)	139
N1—H1B···O18W	0.89	1.85	2.700 (5)	158
N1—H1C···O15ⁱ	0.89	2.16	3.007 (4)	159
N2—H2B···O10	0.91 (5)	1.86 (5)	2.709 (4)	154 (4)
N2—H2B···O16	0.91 (5)	2.49 (4)	3.125 (4)	128 (3)
N3—H3···O9ⁱⁱ	0.86	2.56	2.992 (5)	112
N3—H3···O14ⁱⁱ	0.86	2.25	3.077 (4)	160
O2—H2···O3ⁱⁱⁱ	0.82	1.86	2.657 (3)	165
O17W—H17A···O5^iv	0.84 (2)	2.27 (3)	3.082 (4)	162 (9)
O17W—H17B···O3	0.84 (2)	2.14 (8)	2.864 (4)	144 (12)
O18W—H18A···O17W^v	0.83 (2)	1.83 (2)	2.664 (5)	176 (5)
O18W—H18B···O7	0.83 (2)	2.32 (4)	3.005 (5)	140 (6)
C3—H3B···O10	0.97	2.59	3.210 (4)	122
C9—H9···O8^vi	0.93	2.40	3.177 (4)	141
C17—H17···O11^iv	0.93	2.36	3.177 (3)	147

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

Acknowledgements

MS thanks the UGC Networking Centre, School of Chemistry, University of Hyderabad, India, for the award of a Visiting Research Fellowship to use the facilities at the School, which the authors also thank for access to the X-ray diffraction equipment.

References

Bibal, B., Declercq, J. P., Dutasta, J. P., Tinant, B. & Valade, A. G. (2003). Tetrahedron, 59, 5849–5854. Web of Science CSD CrossRef CAS Google Scholar
Braga, D., Maini, L., Polito, M. & Grepioni, F. (2004). Struct. Bond. 111, 1–32. Web of Science CrossRef CAS Google Scholar
Bruker (2004). APEX2, SAINT and XPREP. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854. Web of Science CrossRef CAS IUCr Journals Google Scholar
Harrison, W. T. A., Bindya, S., Ashok, M. A., Yathirajan, H. S. & Narayana, B. (2007). Acta Cryst. E63, o3143. Web of Science CSD CrossRef IUCr Journals Google Scholar
Harrowfield, J. M., Skelton, B. W. & White, A. H. (1995). Aust. J. Chem. 48, 1311–1331. CSD CrossRef CAS Web of Science Google Scholar
Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466–470. Web of Science CrossRef CAS IUCr Journals Google Scholar
Olsher, U., Feinberg, H., Frolow, F. & Shoham, G. (1996). Pure Appl. Chem. 68, 1195–1199. CrossRef CAS Web of Science Google Scholar
Sheldrick, G. M. (2004). SADABS. University of Göttingen, Germany. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Spek, A. L. (2009). Acta Cryst. D65, 148–155. Web of Science CrossRef CAS IUCr Journals Google Scholar
Swamy, M. T., Ashok, M. A., Yathirajan, H. S., Narayana, B. & Bolte, M. (2007). Acta Cryst. E63, o4919. Web of Science CSD CrossRef IUCr Journals Google Scholar
Yang, L., Zhang, T. L., Feng, C. G., Zhang, J. G. & Yu, K. B. (2001). Energ. Mater. 9, 37–39. Google Scholar