Disodium dihydrogen pyridine-2,3,5,6-tetra­carboxyl­ate trihydrate

Hu, F.-H.; Lin, J.-L.

doi:10.1107/S1600536810012870

metal-organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 66| Part 5| May 2010| Page m524

https://doi.org/10.1107/S1600536810012870

Open

access

Disodium dihydrogen pyridine-2,3,5,6-tetracarboxylate trihydrate

Fang-Hong Hu ^a and Jian-Li Lin ^a ^*

^aState Key Laboratory Base of Novel Functional Materials and Preparation Science, Center of Applied Solid State Chemistry Research, Ningbo University, Ningbo, Zhejiang 315211, People's Republic of China
^*Correspondence e-mail: linjianli@nbu.edu.cn

(Received 11 March 2010; accepted 7 April 2010; online 14 April 2010)

In the title compound, 2Na⁺·C₉H₃NO₈²⁻·3H₂O, the asymmetric unit consists of two Na⁺ cations, one dihydrogen pyridine-2,3,5,6-tetracarboxylate dianion (H₂pdtc²⁻) and three water molecules coordinated to the Na⁺ cations. The configuration of the anion is stabilized by intramolecular O—H⋯O hydrogen bonding between vicinal carboxylate/carboxy groups. The Na⁺ cations are bridged by the H₂pdtc²⁻ dianions, generating layers extending infinitely in sheets parallel to (001), and further pillared by the water molecule linkers to build up a three-dimensional framework.

Related literature

For related compounds involving the pyridine-2,3,5,6-tetracarboxylic acid ligand, see: Zhang et al. (2010 ); Yang et al. (2008 ); Sun, Zhou & An (2009 ); Sun, Zhou & Yan (2009 ).

Experimental

Crystal data

2Na⁺·C₉H₃NO₈²⁻·3H₂O
M_r = 353.15
Triclinic, $[P \overline 1]$
a = 5.5844 (11) Å
b = 6.6770 (13) Å
c = 18.631 (4) Å
α = 81.34 (3)°
β = 86.77 (3)°
γ = 68.36 (3)°
V = 638.4 (2) Å³
Z = 2
Mo Kα radiation
μ = 0.23 mm⁻¹
T = 293 K
0.1 × 0.1 × 0.1 mm

Data collection

Rigaku R-AXIS RAPID diffractometer
Absorption correction: multi-scan (ABSCOR; Higashi, 1995 ) T_min = 0.97, T_max = 0.98
5075 measured reflections
2247 independent reflections
1780 reflections with I > 2σ(I)
R_int = 0.018

Refinement

R[F² > 2σ(F²)] = 0.043
wR(F²) = 0.139
S = 1.14
2247 reflections
208 parameters
H-atom parameters constrained
Δρ_max = 0.55 e Å⁻³
Δρ_min = −0.33 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O3—H3⋯O2	0.86	1.55	2.410	175
O7—H7⋯O6	0.86	1.55	2.402	175
O9—H9A⋯O1ⁱ	0.85	2.05	2.900	175
O9—H9B⋯O1ⁱⁱ	0.86	2.11	2.945	161
O10—H10A⋯O2ⁱⁱⁱ	0.88	2.21	3.024	153
O10—H10B⋯O8^iv	0.88	1.86	2.738	173
O11—H11A⋯O4^v	0.89	2.05	2.917	167
O11—H11B⋯O4^iv	0.88	2.08	2.949	170
Symmetry codes: (i) x+1, y, z; (ii) -x+3, -y, -z+1; (iii) x, y+1, z; (iv) x-1, y, z; (v) -x+1, -y+1, -z.

Data collection: RAPID-AUTO (Rigaku, 1998 ); cell refinement: RAPID-AUTO; data reduction: CrystalStructure (Rigaku/MSC, 2004 ); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S1600536810012870/ds2024sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810012870/ds2024Isup2.hkl

checkCIF report

Comment top

A great many metal-polycarboxylate compounds with benzene-1,2,4,5-tetracarboxylic acid (H₄btec) as ligands have been designed and characterized (Zhang et al., 2010). Analogous in structure to H₄btec, only four complexes [Ni(H₂pdtc)(H₂O)₂].3H₂O (Yang et al., 2008), [Zn₄(pdtc)₂(phen)₂(H₂O)₂].20H₂O (Yang et al., 2008), [Cd(H₂pdtc)(H₂O)₃].3H₂O (Sun, Zhou & Yan, 2009) and [Ni₂(pdtc)(H₂O)₃(2,2'-bpy)].4H₂O (Sun, Zhou & An, 2009) about pyridine-2,3,5,6-tetracarboxylic acid (H₄pdtc) have been reported. The four coordination polymers are constructed by linking transition metal centres through the ligands. In this context, we represent a disodium salt of dihydrogen pyridine-2,3,5,6-tetracarboxylate dianion [Na₂(H₂pdtc)(H₂O)₃].

The asymmetric unit of the title compound consisits of two crystallographically independent Na cations, one dihydrogen pyridine-2,3,5,6-tetracarboxylate dianion (H₂pdtc^2-) and three water molecules (Fig. 1). The ligand is deprotonated at 2,5-positioned carboxylate groups. The values of the dihedral angle between the planes of the carboxylic groups and the planar pyridine ring are 3.7 (4)°, 2.0 (5)°, 10.5 (4)°, 2.4 (5)°, respectively. Both Na1 and Na2 ions are seven-coordinated with one N atom, two carboxylate O atoms and four water molecules at Na1 and five carboxylate O atoms and two water molecules at Na2, building highly distorted pentagonal–bipyramidal environment. The average value of the Na—O(water) length [2.494 (2) Å] is closer to the average Na—O (carboxylate) distance [2.498 (2) Å], and both are slightly smaller than the Na—N value [2.654 (2) Å]. The sodium cations are bridged by the (H₂pdtc^2-) to generate layers extending infinitely in sheets parallel to (001) (Fig. 2), and further pillared by the water molecule linkers (Fig. 3) to build up 3D framework, which is found to be stabilized by hydrogen bonds from water molecules to carboxylate O atoms (Table 1).

Related literature top

For related compounds involving the pyridine-2,3,5,6-tetracarboxylic acid ligand, see: Zhang et al. (2010); Yang et al. (2008); Sun, Zhou & An (2009); Sun, Zhou & Yan (2009).

Experimental top

0.0766 g (0.3 mmol) pyridine-2,3,5,6-tetracarboxylic acid and 0.024 g (0.6 mmol) NaOH were successively added to 10.0 ml H₂O and stirred at room temperature for 2 h, and the resulting colorless solution (pH = 3.48) was then transferred to a 50 ml beaker for slow evaporation at room temperature for several months, affording colorless block crystals (yield: 0.05 g).

Structure description top

For related compounds involving the pyridine-2,3,5,6-tetracarboxylic acid ligand, see: Zhang et al. (2010); Yang et al. (2008); Sun, Zhou & An (2009); Sun, Zhou & Yan (2009).

Computing details top

Data collection: RAPID-AUTO (Rigaku, 1998); cell refinement: RAPID-AUTO (Rigaku, 1998); data reduction: CrystalStructure (Rigaku/MSC, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. ORTEP view of the title compound, Displacement ellipsoids are drawn at the 30% probability level. [Symmetry codes: (i) 2 - x, 1 - y, 1 - z; (ii) 3 - x, 1 - y, 1 - z; (iii) 2 - x, 1 - y, -z; (iv) x - 1, y - 1, z; (v) x, y - 1, z; (vi) 1 - x, -y, -z.]
	Fig. 2. 2D layer _∞[Na₂(H₂pdtc)] parallel to (001) generated from bridging sodium cations and (H₂pdtc^2-).
	Fig. 3. 3D framework built from linking _∞[Na₂(H₂pdtc)] layers by the water molecules (the water molecule linkers are marked in green)

Disodium dihydrogen pyridine-2,3,5,6-tetracarboxylate trihydrate top

Crystal data top

2Na⁺·C₉H₃NO₈²⁻·3H₂O	Z = 2
M_r = 353.15	F(000) = 360
Triclinic, P1	D_x = 1.837 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 5.5844 (11) Å	Cell parameters from 4730 reflections
b = 6.6770 (13) Å	θ = 3.3–27.5°
c = 18.631 (4) Å	µ = 0.23 mm⁻¹
α = 81.34 (3)°	T = 293 K
β = 86.77 (3)°	Block, colourless
γ = 68.36 (3)°	0.1 × 0.1 × 0.1 mm
V = 638.4 (2) Å³

Data collection top

Rigaku R-AXIS RAPID diffractometer	2247 independent reflections
Radiation source: fine-focus sealed tube	1780 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.018
Detector resolution: 0 pixels mm^-1	θ_max = 25.0°, θ_min = 3.3°
ω scans	h = −6→6
Absorption correction: multi-scan (ABSCOR; Higashi, 1995)	k = −7→7
T_min = 0.97, T_max = 0.98	l = −22→22
5075 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)] = 0.043	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.139	H-atom parameters constrained
S = 1.14	w = 1/[σ²(F_o²) + (0.0916P)² + 0.0526P] where P = (F_o² + 2F_c²)/3
2247 reflections	(Δ/σ)_max < 0.001
208 parameters	Δρ_max = 0.55 e Å⁻³
0 restraints	Δρ_min = −0.33 e Å⁻³

Crystal data top

2Na⁺·C₉H₃NO₈²⁻·3H₂O	γ = 68.36 (3)°
M_r = 353.15	V = 638.4 (2) Å³
Triclinic, P1	Z = 2
a = 5.5844 (11) Å	Mo Kα radiation
b = 6.6770 (13) Å	µ = 0.23 mm⁻¹
c = 18.631 (4) Å	T = 293 K
α = 81.34 (3)°	0.1 × 0.1 × 0.1 mm
β = 86.77 (3)°

Data collection top

Rigaku R-AXIS RAPID diffractometer	2247 independent reflections
Absorption correction: multi-scan (ABSCOR; Higashi, 1995)	1780 reflections with I > 2σ(I)
T_min = 0.97, T_max = 0.98	R_int = 0.018
5075 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.043	0 restraints
wR(F²) = 0.139	H-atom parameters constrained
S = 1.14	Δρ_max = 0.55 e Å⁻³
2247 reflections	Δρ_min = −0.33 e Å⁻³
208 parameters

Special details top

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 > 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
Na1	1.28244 (19)	0.41119 (18)	0.44136 (5)	0.0360 (3)
Na2	0.70103 (18)	0.05082 (15)	0.05556 (5)	0.0275 (3)
N	1.2379 (4)	0.4267 (3)	0.29938 (10)	0.0234 (5)
C1	1.1039 (4)	0.3240 (4)	0.27451 (12)	0.0222 (5)
C2	1.0250 (4)	0.3696 (4)	0.20111 (12)	0.0227 (5)
C3	1.0921 (4)	0.5287 (4)	0.15822 (12)	0.0225 (5)
H3A	1.0392	0.5653	0.1100	0.027*
C4	1.2339 (4)	0.6372 (4)	0.18300 (12)	0.0205 (5)
C5	1.3080 (4)	0.5774 (4)	0.25638 (12)	0.0213 (5)
C6	1.0527 (5)	0.1626 (4)	0.33584 (13)	0.0280 (6)
O1	1.1267 (4)	0.1553 (3)	0.39697 (9)	0.0364 (5)
O2	0.9322 (4)	0.0429 (3)	0.32087 (10)	0.0408 (5)
C7	0.8762 (5)	0.2689 (4)	0.16184 (13)	0.0252 (5)
O3	0.7999 (4)	0.1219 (3)	0.19559 (9)	0.0361 (5)
H3	0.8543	0.0954	0.2396	0.043*
O4	0.8325 (3)	0.3309 (3)	0.09639 (9)	0.0299 (4)
C8	1.2832 (4)	0.8074 (4)	0.12553 (12)	0.0231 (5)
O5	1.1680 (3)	0.8518 (3)	0.06780 (9)	0.0295 (4)
O6	1.4448 (3)	0.8925 (3)	0.13981 (9)	0.0335 (5)
C9	1.4680 (5)	0.6635 (4)	0.29836 (13)	0.0270 (6)
O7	1.5562 (4)	0.8069 (3)	0.26636 (10)	0.0385 (5)
H7	1.5260	0.8359	0.2205	0.046*
O8	1.5129 (4)	0.5911 (3)	0.36238 (9)	0.0437 (5)
O9	1.6891 (4)	0.2384 (3)	0.49492 (11)	0.0466 (5)
H9A	1.8156	0.2081	0.4655	0.056*
H9B	1.7251	0.1117	0.5202	0.056*
O10	0.8582 (4)	0.6942 (3)	0.43369 (10)	0.0363 (5)
H10A	0.8616	0.8205	0.4131	0.044*
H10B	0.7414	0.6720	0.4094	0.044*
O11	0.2943 (3)	0.2647 (3)	0.00399 (9)	0.0304 (4)
H11A	0.2605	0.3963	−0.0208	0.037*
H11B	0.1455	0.2949	0.0272	0.037*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Na1	0.0340 (6)	0.0478 (6)	0.0265 (6)	−0.0181 (5)	−0.0043 (4)	0.0044 (4)
Na2	0.0285 (5)	0.0318 (5)	0.0256 (5)	−0.0155 (4)	−0.0043 (4)	−0.0008 (4)
N	0.0272 (10)	0.0255 (10)	0.0180 (10)	−0.0103 (9)	−0.0006 (8)	−0.0027 (8)
C1	0.0233 (11)	0.0233 (12)	0.0200 (12)	−0.0090 (10)	−0.0002 (9)	−0.0012 (9)
C2	0.0238 (11)	0.0224 (11)	0.0227 (12)	−0.0092 (10)	−0.0015 (9)	−0.0036 (9)
C3	0.0277 (12)	0.0245 (12)	0.0150 (11)	−0.0092 (10)	−0.0040 (9)	−0.0018 (9)
C4	0.0223 (11)	0.0206 (11)	0.0190 (11)	−0.0087 (10)	0.0001 (9)	−0.0020 (9)
C5	0.0239 (11)	0.0210 (11)	0.0189 (11)	−0.0087 (10)	0.0008 (9)	−0.0012 (9)
C6	0.0314 (13)	0.0300 (13)	0.0237 (13)	−0.0146 (11)	0.0001 (10)	0.0013 (10)
O1	0.0510 (12)	0.0438 (11)	0.0195 (10)	−0.0264 (10)	−0.0049 (8)	0.0057 (8)
O2	0.0608 (13)	0.0453 (11)	0.0292 (10)	−0.0379 (11)	−0.0054 (9)	0.0056 (8)
C7	0.0299 (13)	0.0243 (12)	0.0228 (13)	−0.0113 (11)	−0.0018 (10)	−0.0031 (10)
O3	0.0517 (12)	0.0412 (10)	0.0275 (10)	−0.0324 (10)	−0.0060 (8)	0.0008 (8)
O4	0.0415 (10)	0.0320 (9)	0.0227 (9)	−0.0210 (8)	−0.0068 (7)	−0.0009 (7)
C8	0.0273 (12)	0.0261 (12)	0.0169 (11)	−0.0116 (10)	0.0006 (9)	−0.0017 (9)
O5	0.0327 (9)	0.0376 (10)	0.0201 (9)	−0.0176 (8)	−0.0049 (7)	0.0046 (7)
O6	0.0455 (11)	0.0461 (11)	0.0213 (9)	−0.0337 (10)	−0.0057 (8)	0.0040 (8)
C9	0.0331 (13)	0.0292 (13)	0.0226 (13)	−0.0171 (11)	−0.0036 (10)	0.0007 (10)
O7	0.0557 (12)	0.0519 (12)	0.0234 (9)	−0.0394 (11)	−0.0088 (8)	0.0027 (8)
O8	0.0642 (14)	0.0651 (13)	0.0189 (10)	−0.0469 (12)	−0.0146 (9)	0.0090 (9)
O9	0.0342 (11)	0.0582 (13)	0.0355 (11)	−0.0105 (10)	0.0001 (9)	0.0132 (10)
O10	0.0387 (10)	0.0452 (11)	0.0304 (10)	−0.0236 (9)	−0.0077 (8)	0.0033 (8)
O11	0.0286 (9)	0.0302 (9)	0.0296 (9)	−0.0098 (8)	0.0007 (7)	0.0019 (7)

Geometric parameters (Å, º) top

Na1—O9	2.337 (2)	C3—H3A	0.9300
Na1—O8	2.379 (2)	C4—C5	1.406 (3)
Na1—O10	2.420 (2)	C4—C8	1.531 (3)
Na1—O1	2.442 (2)	C5—C9	1.528 (3)
Na1—O10ⁱ	2.498 (2)	C6—O1	1.221 (3)
Na1—N	2.654 (2)	C6—O2	1.287 (3)
Na1—O9ⁱⁱ	2.835 (3)	C7—O4	1.235 (3)
Na1—Na1ⁱ	3.657 (2)	C7—O3	1.278 (3)
Na1—Na1ⁱⁱ	3.948 (2)	O3—H3	0.8603
Na2—O11	2.358 (2)	C8—O5	1.225 (3)
Na2—O5ⁱⁱⁱ	2.4395 (18)	C8—O6	1.288 (3)
Na2—O6^iv	2.4477 (19)	O5—Na2ⁱⁱⁱ	2.4395 (18)
Na2—O5^v	2.457 (2)	O5—Na2^viii	2.457 (2)
Na2—O4	2.4738 (18)	O6—Na2^ix	2.4477 (19)
Na2—O11^vi	2.516 (2)	C9—O8	1.221 (3)
Na2—O3	2.840 (2)	C9—O7	1.287 (3)
Na2—C7	3.022 (3)	O7—H7	0.8596
Na2—Na2^vi	3.444 (2)	O9—Na1ⁱⁱ	2.835 (3)
Na2—Na2^vii	3.724 (2)	O9—H9A	0.8516
N—C1	1.325 (3)	O9—H9B	0.8625
N—C5	1.349 (3)	O10—Na1ⁱ	2.498 (2)
C1—C2	1.414 (3)	O10—H10A	0.8790
C1—C6	1.539 (3)	O10—H10B	0.8816
C2—C3	1.382 (3)	O11—Na2^vi	2.516 (2)
C2—C7	1.519 (3)	O11—H11A	0.8872
C3—C4	1.389 (3)	O11—H11B	0.8833

O9—Na1—O8	81.23 (8)	O11—Na2—Na2^vii	120.83 (6)
O9—Na1—O10	151.17 (9)	O5ⁱⁱⁱ—Na2—Na2^vii	40.67 (5)
O8—Na1—O10	99.80 (8)	O6^iv—Na2—Na2^vii	146.74 (7)
O9—Na1—O1	112.23 (9)	O5^v—Na2—Na2^vii	40.31 (4)
O8—Na1—O1	120.07 (7)	O4—Na2—Na2^vii	83.00 (6)
O10—Na1—O1	92.37 (7)	O11^vi—Na2—Na2^vii	79.10 (6)
O9—Na1—O10ⁱ	81.74 (8)	O3—Na2—Na2^vii	108.88 (6)
O8—Na1—O10ⁱ	150.12 (7)	C7—Na2—Na2^vii	93.42 (6)
O10—Na1—O10ⁱ	83.92 (8)	Na2^vi—Na2—Na2^vii	102.29 (5)
O1—Na1—O10ⁱ	89.14 (7)	C1—N—C5	122.15 (19)
O9—Na1—N	119.02 (8)	C1—N—Na1	120.01 (14)
O8—Na1—N	62.02 (6)	C5—N—Na1	116.33 (15)
O10—Na1—N	85.55 (8)	N—C1—C2	121.20 (19)
O1—Na1—N	60.81 (6)	N—C1—C6	110.34 (19)
O10ⁱ—Na1—N	147.64 (7)	C2—C1—C6	128.5 (2)
O9—Na1—O9ⁱⁱ	80.93 (8)	C3—C2—C1	116.0 (2)
O8—Na1—O9ⁱⁱ	70.80 (7)	C3—C2—C7	114.6 (2)
O10—Na1—O9ⁱⁱ	72.45 (7)	C1—C2—C7	129.44 (19)
O1—Na1—O9ⁱⁱ	163.26 (7)	C2—C3—C4	123.8 (2)
O10ⁱ—Na1—O9ⁱⁱ	82.40 (7)	C2—C3—H3A	118.1
N—Na1—O9ⁱⁱ	123.02 (7)	C4—C3—H3A	118.1
O9—Na1—Na1ⁱ	118.79 (7)	C3—C4—C5	116.01 (19)
O8—Na1—Na1ⁱ	134.81 (8)	C3—C4—C8	114.27 (19)
O10—Na1—Na1ⁱ	42.77 (5)	C5—C4—C8	129.72 (19)
O1—Na1—Na1ⁱ	90.98 (6)	N—C5—C4	120.8 (2)
O10ⁱ—Na1—Na1ⁱ	41.15 (5)	N—C5—C9	111.11 (19)
N—Na1—Na1ⁱ	121.70 (7)	C4—C5—C9	128.05 (19)
O9ⁱⁱ—Na1—Na1ⁱ	73.15 (6)	O1—C6—O2	122.8 (2)
O9—Na1—Na1ⁱⁱ	45.17 (6)	O1—C6—C1	118.3 (2)
O8—Na1—Na1ⁱⁱ	70.94 (5)	O2—C6—C1	118.9 (2)
O10—Na1—Na1ⁱⁱ	107.58 (7)	C6—O1—Na1	127.72 (16)
O1—Na1—Na1ⁱⁱ	155.73 (7)	O4—C7—O3	120.7 (2)
O10ⁱ—Na1—Na1ⁱⁱ	79.63 (5)	O4—C7—C2	118.50 (19)
N—Na1—Na1ⁱⁱ	132.72 (6)	O3—C7—C2	120.8 (2)
O9ⁱⁱ—Na1—Na1ⁱⁱ	35.76 (5)	O4—C7—Na2	52.54 (11)
Na1ⁱ—Na1—Na1ⁱⁱ	94.41 (5)	O3—C7—Na2	69.52 (13)
O11—Na2—O5ⁱⁱⁱ	80.18 (7)	C2—C7—Na2	164.48 (15)
O11—Na2—O6^iv	82.71 (7)	C7—O3—Na2	85.55 (14)
O5ⁱⁱⁱ—Na2—O6^iv	150.56 (7)	C7—O3—H3	107.5
O11—Na2—O5^v	161.10 (7)	Na2—O3—H3	160.1
O5ⁱⁱⁱ—Na2—O5^v	80.98 (7)	C7—O4—Na2	104.12 (14)
O6^iv—Na2—O5^v	113.75 (7)	O5—C8—O6	123.9 (2)
O11—Na2—O4	101.38 (7)	O5—C8—C4	117.35 (19)
O5ⁱⁱⁱ—Na2—O4	89.54 (6)	O6—C8—C4	118.8 (2)
O6^iv—Na2—O4	117.34 (7)	C8—O5—Na2ⁱⁱⁱ	130.76 (15)
O5^v—Na2—O4	79.82 (7)	C8—O5—Na2^viii	123.43 (15)
O11—Na2—O11^vi	90.16 (7)	Na2ⁱⁱⁱ—O5—Na2^viii	99.02 (7)
O5ⁱⁱⁱ—Na2—O11^vi	78.64 (7)	C8—O6—Na2^ix	128.80 (14)
O6^iv—Na2—O11^vi	77.63 (6)	O8—C9—O7	121.0 (2)
O5^v—Na2—O11^vi	84.77 (7)	O8—C9—C5	118.5 (2)
O4—Na2—O11^vi	161.90 (7)	O7—C9—C5	120.5 (2)
O11—Na2—O3	117.19 (7)	C9—O7—H7	112.8
O5ⁱⁱⁱ—Na2—O3	134.97 (6)	C9—O8—Na1	126.87 (16)
O6^iv—Na2—O3	74.36 (6)	Na1—O9—Na1ⁱⁱ	99.07 (8)
O5^v—Na2—O3	77.80 (7)	Na1—O9—H9A	115.5
O4—Na2—O3	47.92 (6)	Na1ⁱⁱ—O9—H9A	104.4
O11^vi—Na2—O3	137.20 (7)	Na1—O9—H9B	118.8
O11—Na2—C7	113.48 (7)	Na1ⁱⁱ—O9—H9B	120.3
O5ⁱⁱⁱ—Na2—C7	110.79 (7)	H9A—O9—H9B	98.8
O6^iv—Na2—C7	97.96 (7)	Na1—O10—Na1ⁱ	96.08 (8)
O5^v—Na2—C7	74.82 (7)	Na1—O10—H10A	112.2
O4—Na2—C7	23.34 (6)	Na1ⁱ—O10—H10A	129.4
O11^vi—Na2—C7	155.41 (7)	Na1—O10—H10B	116.3
O3—Na2—C7	24.93 (6)	Na1ⁱ—O10—H10B	97.7
O11—Na2—Na2^vi	46.94 (5)	H10A—O10—H10B	105.2
O5ⁱⁱⁱ—Na2—Na2^vi	74.89 (5)	Na2—O11—Na2^vi	89.84 (7)
O6^iv—Na2—Na2^vi	75.92 (5)	Na2—O11—H11A	122.9
O5^v—Na2—Na2^vi	125.55 (7)	Na2^vi—O11—H11A	121.8
O4—Na2—Na2^vi	146.06 (7)	Na2—O11—H11B	125.4
O11^vi—Na2—Na2^vi	43.23 (5)	Na2^vi—O11—H11B	100.3
O3—Na2—Na2^vi	148.10 (6)	H11A—O11—H11B	96.5
C7—Na2—Na2^vi	159.59 (7)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3···O2	0.86	1.55	2.410	175
O7—H7···O6	0.86	1.55	2.402	175
O9—H9A···O1^x	0.85	2.05	2.900	175
O9—H9B···O1^xi	0.86	2.11	2.945	161
O10—H10A···O2^viii	0.88	2.21	3.024	153
O10—H10B···O8^xii	0.88	1.86	2.738	173
O11—H11A···O4^xiii	0.89	2.05	2.917	167
O11—H11B···O4^xii	0.88	2.08	2.949	170

Symmetry codes: (viii) x, y+1, z; (x) x+1, y, z; (xi) −x+3, −y, −z+1; (xii) x−1, y, z; (xiii) −x+1, −y+1, −z.

Experimental details

Crystal data
Chemical formula	2Na⁺·C₉H₃NO₈²⁻·3H₂O
M_r	353.15
Crystal system, space group	Triclinic, P1
Temperature (K)	293
a, b, c (Å)	5.5844 (11), 6.6770 (13), 18.631 (4)
α, β, γ (°)	81.34 (3), 86.77 (3), 68.36 (3)
V (Å³)	638.4 (2)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.23
Crystal size (mm)	0.1 × 0.1 × 0.1

Data collection
Diffractometer	Rigaku R-AXIS RAPID
Absorption correction	Multi-scan (ABSCOR; Higashi, 1995)
T_min, T_max	0.97, 0.98
No. of measured, independent and observed [I > 2σ(I)] reflections	5075, 2247, 1780
R_int	0.018
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.043, 0.139, 1.14
No. of reflections	2247
No. of parameters	208
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.55, −0.33

Computer programs: RAPID-AUTO (Rigaku, 1998), CrystalStructure (Rigaku/MSC, 2004), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3···O2	0.86	1.55	2.410	175
O7—H7···O6	0.86	1.55	2.402	175
O9—H9A···O1ⁱ	0.85	2.05	2.900	175
O9—H9B···O1ⁱⁱ	0.86	2.11	2.945	161
O10—H10A···O2ⁱⁱⁱ	0.88	2.21	3.024	153
O10—H10B···O8^iv	0.88	1.86	2.738	173
O11—H11A···O4^v	0.89	2.05	2.917	167
O11—H11B···O4^iv	0.88	2.08	2.949	170

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

Acknowledgements

This project was supported by the National Natural Science Foundation of China (grant No. 20072022), the Science and Technology Department of Zhejiang Province (grant No. 2006C21105), and the Education Department of Zhejiang Province. The authors also extend grateful thanks to the K. C. Wong Magna Fund of Ningbo University.

References

Higashi, T. (1995). ABSCOR. Rigaku Corporation, Tokyo, Japan. Google Scholar
Rigaku (1998). RAPID-AUTO. Rigaku Corporation, Tokyo, Japan. Google Scholar
Rigaku/MSC (2004). CrystalStructure. Rigaku/MSC Inc., The Woodlands, Texas, USA. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Sun, X. J., Zhou, J. F. & An, L. T. (2009). Z. Kristallogr. New Cryst. Struct. 224, 469–470. CAS Google Scholar
Sun, X. J., Zhou, J. F. & Yan, M. Z. (2009). Chin. J. Inorg. Chem. 25, 1483–1486. CAS Google Scholar
Yang, A. H., Zhang, H., Gao, H. L., Zhang, W. Q., He, L. & Cui, J. Z. (2008). Cryst. Growth Des. 8, 3354–3359. Web of Science CSD CrossRef CAS Google Scholar
Zhang, N., Li, M. X., Wang, Z. X., Shao, M. & Zhu, S. R. (2010). Inorg. Chim. Acta, 363, 8–14. Web of Science CSD CrossRef CAS Google Scholar