Diaqua­bis(5-carb­oxy-2-methyl-1H-imidazole-4-carboxyl­ato-κ2N3,O4)cobalt(II) dimethyl­formamide disolvate

Tang, S.-P.

doi:10.1107/S1600536809012902

metal-organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 65| Part 5| May 2009| Page m504

doi:10.1107/S1600536809012902

Open

access

Diaquabis(5-carboxy-2-methyl-1H-imidazole-4-carboxylato-κ²N³,O⁴)cobalt(II) dimethylformamide disolvate

Si-Ping Tang ^a ^*

^aDepartment of Chemistry and Material Science, Hengyang Normal University, Hengyang, Hunan 421008, People's Republic of China.
^*Correspondence e-mail: sptang88@163.com

(Received 4 April 2009; accepted 5 April 2009; online 10 April 2009)

In the title compound, [Co(C₆H₅N₂O₄)₂(H₂O)₂]·2C₃H₇NO, the Co^II ion lies on an inversion center and adopts a slightly distorted CoN₂O₄ octahedral geometry binding two bidentate chelating 5-carboxy-2-methyl-1H-imidazole-4-carboxylate (H₂MIDA⁻) monoanionic ligands and two axial aqua ligands. In the crystal structure, intermolecular O—H⋯O hydrogen bonds link neighboring molecules, generating a two-dimensional framework containing eight-membered H₄O₄ rings. In addition, the dimethylformamide solvent molecules are hydrogen bonded to the two-dimensional framework via the NH groups of the H₂MIDA⁻ ligands.

Related literature

For background to N-heterocyclic carboxylic acids as ligands in coordination complexes, see: Gao et al. (2004 ); Shimizu et al. (2004 ); Zhang et al. (2006 ). For related structures, see: Liu et al. (2007 ); Nie et al. (2007 ); Zeng et al. (2008 ).

Experimental

Crystal data

[Co(C₆H₅N₂O₄)₂(H₂O)₂]·2C₃H₇NO
M_r = 579.39
Triclinic, $[P \overline 1]$
a = 7.1979 (11) Å
b = 9.2180 (15) Å
c = 10.8659 (17) Å
α = 65.173 (2)°
β = 83.459 (2)°
γ = 68.254 (2)°
V = 607.02 (17) Å³
Z = 1
Mo Kα radiation
μ = 0.78 mm⁻¹
T = 123 K
0.20 × 0.15 × 0.14 mm

Data collection

Bruker SMART APEX area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.859, T_max = 0.899
4588 measured reflections
2335 independent reflections
2176 reflections with I > 2σ(I)
R_int = 0.026

Refinement

R[F² > 2σ(F²)] = 0.039
wR(F²) = 0.106
S = 1.06
2335 reflections
172 parameters
1 restraint
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.65 e Å⁻³
Δρ_min = −0.49 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2⋯O5ⁱ	0.86	1.83	2.670 (2)	166
O2—H2A⋯O3	0.863 (10)	1.593 (11)	2.452 (2)	173 (3)
O1W—H1W2⋯O1ⁱⁱ	0.85	1.91	2.7579 (19)	178
O1W—H1W1⋯O1ⁱⁱⁱ	0.85	2.03	2.847 (2)	160
Symmetry codes: (i) -x+1, -y, -z+1; (ii) -x+1, -y+1, -z+1; (iii) x, y+1, z.

Data collection: SMART (Bruker, 2002 ); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT; 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: SHELXTL.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809012902/sj2611sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809012902/sj2611Isup2.hkl

checkCIF report

Comment top

N-heterocyclic carboxylic acids have attracted considerable interests as ligands in metal complexes because of their structural diversity as multidentate chelating or bridging ligands (Gao et al., 2004; Shimizu et al., 2004; Zhang et al., 2006). Recently, 2-methyl-1H-imidazole-4,5- dicarboxylic acid (H₃MIDA) has been used as a chelating ligand to generate mononuclear complexes with cadmium (II), cobalt (II) and manganese (II) ions (Liu et al., 2007; Nie et al., 2007; Zeng et al., 2008). We report here the synthesis and structure of a new cobalt (II) complex incorporating H₃MIDA.

The title compound is composed of one Co (II) ion, two mono-deprotonated H₂MIDA ligands, two aqua ligands and two DMF solvent molecules, Fig 1. The Co (II) cation lies on a crystallographic inversion center and has a distorted octahedral geometry with the basal plane occupied by two carboxylate O atoms and two N atoms from two chelating H₂MIDA^- ligands. There are two axial aqua ligands. In the H₂MIDA ligand, the carboxyl and carboxylate groups form an intramolecular hydrogen bond with an O···O distance of 2.452 (2) Å.

In the crystal packing, each aqua ligand is involved in two intermolecular O—H···O hydrogen bonds with two carboxyl O atoms from two neighboring molecules to genetrate a two-dimensional supramolecular structure (Fig. 2), in which two aqua ligands and two carboxyl O atoms form a H₄O₄ eight-membered ring. In addition, the DMF solvates are hydrogen-bonded to the two-dimensional framework via the –NH groups of the H₂MIDA^- ligands.

Related literature top

For background to N-heterocyclic carboxylic acids as ligands in coordination complexes, see: Gao et al. (2004); Shimizu et al. (2004); Zhang et al. (2006). For related structures, see: Liu et al. (2007); Nie et al. (2007); Zeng et al. (2008).

Experimental top

A solution of cobalt perchlorate hexahydrate (73.2 mg, 0.2 mmol) and H₃MIDA (15.8 mg, 0.1 mmol) in DMF (6 ml) and methanol (1 ml) was stirred for 5 h. After filtering, the filtrate was left for about two months and pink, block-like crystals of the title compound appeared. Yield: 11 mg (38%).

Computing details top

Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT (Bruker, 2002); 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: SHELXTL (Sheldrick, 2008).

Figures top

	Fig. 1. The title molecule with displacement ellipsoids drawn at the 50% probability level, and with the H atoms shown as spheres of arbitrary radii.
	Fig. 2. Packing diagram of the title compound showing the intra/intermolecular O—H···O hydrogen bonds as dashed lines. The H atoms not involved in hydrogen bonds and the DMF solvate molecules have been omitted for clarity.

Diaquabis(5-carboxy-2-methyl-1H-imidazole-4-carboxylato- κ²N³,O⁴)cobalt(II) dimethylformamide disolvate top

Crystal data top

[Co(C₆H₅N₂O₄)₂(H₂O)₂]·2C₃H₇NO	Z = 1
M_r = 579.39	F(000) = 301
Triclinic, P1	D_x = 1.585 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.1979 (11) Å	Cell parameters from 3423 reflections
b = 9.2180 (15) Å	θ = 2.6–27.8°
c = 10.8659 (17) Å	µ = 0.78 mm⁻¹
α = 65.173 (2)°	T = 123 K
β = 83.459 (2)°	Block, pink
γ = 68.254 (2)°	0.20 × 0.15 × 0.14 mm
V = 607.02 (17) Å³

Data collection top

Bruker SMART APEX area-detector diffractometer	2335 independent reflections
Radiation source: fine-focus sealed tube	2176 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.026
ϕ and ω scans	θ_max = 26.0°, θ_min = 2.6°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −8→7
T_min = 0.859, T_max = 0.899	k = −11→11
4588 measured reflections	l = −13→13

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)] = 0.039	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.106	H atoms treated by a mixture of independent and constrained refinement
S = 1.06	w = 1/[σ²(F_o²) + (0.0631P)² + 0.2477P] where P = (F_o² + 2F_c²)/3
2335 reflections	(Δ/σ)_max < 0.001
172 parameters	Δρ_max = 0.65 e Å⁻³
1 restraint	Δρ_min = −0.49 e Å⁻³

Crystal data top

[Co(C₆H₅N₂O₄)₂(H₂O)₂]·2C₃H₇NO	γ = 68.254 (2)°
M_r = 579.39	V = 607.02 (17) Å³
Triclinic, P1	Z = 1
a = 7.1979 (11) Å	Mo Kα radiation
b = 9.2180 (15) Å	µ = 0.78 mm⁻¹
c = 10.8659 (17) Å	T = 123 K
α = 65.173 (2)°	0.20 × 0.15 × 0.14 mm
β = 83.459 (2)°

Data collection top

Bruker SMART APEX area-detector diffractometer	2335 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	2176 reflections with I > 2σ(I)
T_min = 0.859, T_max = 0.899	R_int = 0.026
4588 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.039	1 restraint
wR(F²) = 0.106	H atoms treated by a mixture of independent and constrained refinement
S = 1.06	Δρ_max = 0.65 e Å⁻³
2335 reflections	Δρ_min = −0.49 e Å⁻³
172 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
Co1	0.0000	1.0000	0.5000	0.01688 (15)
O4	0.1583 (2)	0.97632 (18)	0.32480 (14)	0.0200 (3)
O1W	0.2666 (2)	0.96647 (18)	0.58550 (14)	0.0214 (3)
H1W2	0.3716	0.9017	0.5643	0.032*
H1W1	0.2857	1.0585	0.5685	0.032*
O3	0.3261 (2)	0.78687 (18)	0.23787 (14)	0.0220 (3)
O2	0.4205 (2)	0.47831 (19)	0.30617 (15)	0.0233 (3)
H2A	0.391 (4)	0.5850 (15)	0.288 (3)	0.035*
O1	0.3990 (2)	0.24920 (18)	0.48355 (16)	0.0241 (3)
O5	0.8297 (3)	−0.1528 (2)	0.20333 (17)	0.0343 (4)
N1	0.0922 (2)	0.7355 (2)	0.55599 (16)	0.0171 (4)
N2	0.1798 (2)	0.4572 (2)	0.62169 (17)	0.0181 (4)
H2	0.1932	0.3523	0.6713	0.022*
N3	0.6518 (3)	0.1293 (2)	0.08740 (18)	0.0296 (4)
C6	0.2260 (3)	0.8282 (3)	0.33158 (19)	0.0179 (4)
C5	0.1936 (3)	0.6909 (2)	0.4550 (2)	0.0174 (4)
C4	0.2493 (3)	0.5176 (2)	0.4945 (2)	0.0173 (4)
C3	0.3636 (3)	0.4049 (3)	0.4250 (2)	0.0194 (4)
C2	0.0862 (3)	0.5915 (2)	0.6556 (2)	0.0181 (4)
C1	−0.0105 (3)	0.5776 (3)	0.7860 (2)	0.0247 (5)
H1A	0.0882	0.5048	0.8597	0.037*
H1B	−0.1121	0.5297	0.7961	0.037*
H1C	−0.0703	0.6892	0.7866	0.037*
C7	0.4556 (5)	0.2630 (4)	0.0431 (3)	0.0559 (8)
H7A	0.3539	0.2136	0.0754	0.084*
H7B	0.4450	0.3176	−0.0543	0.084*
H7C	0.4384	0.3461	0.0788	0.084*
C8	0.8227 (5)	0.1820 (4)	0.0586 (3)	0.0480 (7)
H8A	0.8213	0.2500	−0.0369	0.072*
H8B	0.9434	0.0827	0.0854	0.072*
H8C	0.8175	0.2484	0.1081	0.072*
C9	0.6694 (4)	−0.0318 (3)	0.1589 (2)	0.0309 (5)
H9	0.5524	−0.0563	0.1773	0.037*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Co1	0.0189 (2)	0.0105 (2)	0.0213 (2)	−0.00437 (16)	0.00295 (15)	−0.00778 (16)
O4	0.0233 (8)	0.0124 (7)	0.0237 (7)	−0.0055 (6)	0.0032 (5)	−0.0082 (6)
O1W	0.0208 (7)	0.0153 (7)	0.0301 (8)	−0.0054 (6)	0.0030 (6)	−0.0126 (6)
O3	0.0273 (8)	0.0180 (7)	0.0221 (7)	−0.0078 (6)	0.0063 (6)	−0.0110 (6)
O2	0.0279 (8)	0.0168 (7)	0.0297 (8)	−0.0076 (6)	0.0065 (6)	−0.0151 (7)
O1	0.0227 (8)	0.0146 (8)	0.0375 (8)	−0.0059 (6)	0.0044 (6)	−0.0144 (6)
O5	0.0393 (10)	0.0179 (8)	0.0395 (9)	−0.0122 (7)	0.0049 (7)	−0.0051 (7)
N1	0.0172 (9)	0.0136 (8)	0.0209 (8)	−0.0043 (7)	0.0028 (6)	−0.0087 (7)
N2	0.0200 (8)	0.0098 (8)	0.0240 (8)	−0.0056 (7)	0.0010 (6)	−0.0063 (7)
N3	0.0419 (11)	0.0206 (9)	0.0236 (9)	−0.0106 (8)	0.0034 (8)	−0.0076 (7)
C6	0.0152 (9)	0.0167 (10)	0.0228 (10)	−0.0060 (8)	0.0005 (7)	−0.0086 (8)
C5	0.0161 (9)	0.0155 (10)	0.0218 (9)	−0.0049 (8)	0.0017 (7)	−0.0094 (8)
C4	0.0163 (9)	0.0147 (10)	0.0227 (9)	−0.0057 (8)	0.0003 (7)	−0.0091 (8)
C3	0.0152 (9)	0.0160 (10)	0.0303 (10)	−0.0045 (8)	−0.0002 (8)	−0.0130 (9)
C2	0.0172 (10)	0.0128 (10)	0.0243 (10)	−0.0054 (8)	−0.0001 (7)	−0.0074 (8)
C1	0.0299 (11)	0.0205 (11)	0.0245 (10)	−0.0105 (9)	0.0045 (8)	−0.0096 (9)
C7	0.0534 (15)	0.0351 (15)	0.0471 (15)	0.0034 (13)	0.0177 (13)	−0.0078 (12)
C8	0.0650 (16)	0.0353 (14)	0.0426 (14)	−0.0331 (13)	−0.0161 (13)	0.0028 (12)
C9	0.0366 (13)	0.0268 (12)	0.0336 (12)	−0.0164 (11)	0.0115 (10)	−0.0143 (10)

Geometric parameters (Å, º) top

Co1—O1Wⁱ	2.0895 (14)	N2—H2	0.8600
Co1—O1W	2.0895 (14)	N3—C9	1.319 (3)
Co1—N1ⁱ	2.0982 (16)	N3—C8	1.440 (3)
Co1—N1	2.0982 (16)	N3—C7	1.453 (3)
Co1—O4	2.1543 (14)	C6—C5	1.476 (3)
Co1—O4ⁱ	2.1543 (14)	C5—C4	1.374 (3)
O4—C6	1.240 (2)	C4—C3	1.486 (3)
O1W—H1W2	0.8500	C2—C1	1.482 (3)
O1W—H1W1	0.8500	C1—H1A	0.9600
O3—C6	1.287 (2)	C1—H1B	0.9600
O2—C3	1.282 (3)	C1—H1C	0.9600
O2—H2A	0.863 (10)	C7—H7A	0.9600
O1—C3	1.237 (2)	C7—H7B	0.9600
O5—C9	1.237 (3)	C7—H7C	0.9600
N1—C2	1.327 (3)	C8—H8A	0.9600
N1—C5	1.371 (2)	C8—H8B	0.9600
N2—C2	1.353 (3)	C8—H8C	0.9600
N2—C4	1.368 (3)	C9—H9	0.9300

O1Wⁱ—Co1—O1W	180.00 (8)	N1—C5—C6	117.57 (17)
O1Wⁱ—Co1—N1ⁱ	90.58 (6)	C4—C5—C6	132.78 (18)
O1W—Co1—N1ⁱ	89.42 (6)	N2—C4—C5	105.63 (17)
O1Wⁱ—Co1—N1	89.42 (6)	N2—C4—C3	123.03 (18)
O1W—Co1—N1	90.58 (6)	C5—C4—C3	131.33 (19)
N1ⁱ—Co1—N1	180.0	O1—C3—O2	124.18 (18)
O1Wⁱ—Co1—O4	90.84 (5)	O1—C3—C4	119.29 (19)
O1W—Co1—O4	89.16 (5)	O2—C3—C4	116.53 (17)
N1ⁱ—Co1—O4	101.17 (6)	N1—C2—N2	110.61 (17)
N1—Co1—O4	78.83 (6)	N1—C2—C1	125.33 (18)
O1Wⁱ—Co1—O4ⁱ	89.16 (5)	N2—C2—C1	124.06 (18)
O1W—Co1—O4ⁱ	90.84 (5)	C2—C1—H1A	109.5
N1ⁱ—Co1—O4ⁱ	78.83 (6)	C2—C1—H1B	109.5
N1—Co1—O4ⁱ	101.17 (6)	H1A—C1—H1B	109.5
O4—Co1—O4ⁱ	180.0	C2—C1—H1C	109.5
C6—O4—Co1	113.98 (12)	H1A—C1—H1C	109.5
Co1—O1W—H1W2	114.5	H1B—C1—H1C	109.5
Co1—O1W—H1W1	114.9	N3—C7—H7A	109.5
H1W2—O1W—H1W1	106.7	N3—C7—H7B	109.5
C3—O2—H2A	108.9 (18)	H7A—C7—H7B	109.5
C2—N1—C5	106.13 (15)	N3—C7—H7C	109.5
C2—N1—Co1	142.57 (14)	H7A—C7—H7C	109.5
C5—N1—Co1	111.29 (12)	H7B—C7—H7C	109.5
C2—N2—C4	107.99 (16)	N3—C8—H8A	109.5
C2—N2—H2	126.0	N3—C8—H8B	109.5
C4—N2—H2	126.0	H8A—C8—H8B	109.5
C9—N3—C8	121.9 (2)	N3—C8—H8C	109.5
C9—N3—C7	120.7 (2)	H8A—C8—H8C	109.5
C8—N3—C7	117.2 (2)	H8B—C8—H8C	109.5
O4—C6—O3	123.66 (18)	O5—C9—N3	124.9 (2)
O4—C6—C5	118.29 (17)	O5—C9—H9	117.5
O3—C6—C5	118.04 (17)	N3—C9—H9	117.5
N1—C5—C4	109.64 (17)

O1Wⁱ—Co1—O4—C6	−87.79 (14)	O4—C6—C5—C4	−179.21 (19)
O1W—Co1—O4—C6	92.21 (14)	O3—C6—C5—C4	−0.4 (3)
N1ⁱ—Co1—O4—C6	−178.54 (13)	C2—N2—C4—C5	0.0 (2)
N1—Co1—O4—C6	1.46 (13)	C2—N2—C4—C3	178.91 (17)
O1Wⁱ—Co1—N1—C2	−89.6 (2)	N1—C5—C4—N2	0.0 (2)
O1W—Co1—N1—C2	90.4 (2)	C6—C5—C4—N2	178.5 (2)
O4—Co1—N1—C2	179.4 (2)	N1—C5—C4—C3	−178.80 (19)
O4ⁱ—Co1—N1—C2	−0.6 (2)	C6—C5—C4—C3	−0.3 (4)
O1Wⁱ—Co1—N1—C5	89.19 (13)	N2—C4—C3—O1	−0.1 (3)
O1W—Co1—N1—C5	−90.81 (13)	C5—C4—C3—O1	178.5 (2)
O4—Co1—N1—C5	−1.78 (12)	N2—C4—C3—O2	−179.72 (17)
O4ⁱ—Co1—N1—C5	178.22 (12)	C5—C4—C3—O2	−1.1 (3)
Co1—O4—C6—O3	−179.57 (15)	C5—N1—C2—N2	0.0 (2)
Co1—O4—C6—C5	−0.8 (2)	Co1—N1—C2—N2	178.85 (15)
C2—N1—C5—C4	0.0 (2)	C5—N1—C2—C1	−179.54 (18)
Co1—N1—C5—C4	−179.25 (13)	Co1—N1—C2—C1	−0.7 (4)
C2—N1—C5—C6	−178.74 (17)	C4—N2—C2—N1	0.0 (2)
Co1—N1—C5—C6	2.0 (2)	C4—N2—C2—C1	179.55 (18)
O4—C6—C5—N1	−0.8 (3)	C8—N3—C9—O5	−2.9 (4)
O3—C6—C5—N1	178.00 (16)	C7—N3—C9—O5	−178.2 (2)

Symmetry code: (i) −x, −y+2, −z+1.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2···O5ⁱⁱ	0.86	1.83	2.670 (2)	166
O2—H2A···O3	0.86 (1)	1.59 (1)	2.452 (2)	173 (3)
O1W—H1W2···O1ⁱⁱⁱ	0.85	1.91	2.7579 (19)	178
O1W—H1W1···O1^iv	0.85	2.03	2.847 (2)	160

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

Experimental details

Crystal data
Chemical formula	[Co(C₆H₅N₂O₄)₂(H₂O)₂]·2C₃H₇NO
M_r	579.39
Crystal system, space group	Triclinic, P1
Temperature (K)	123
a, b, c (Å)	7.1979 (11), 9.2180 (15), 10.8659 (17)
α, β, γ (°)	65.173 (2), 83.459 (2), 68.254 (2)
V (Å³)	607.02 (17)
Z	1
Radiation type	Mo Kα
µ (mm⁻¹)	0.78
Crystal size (mm)	0.20 × 0.15 × 0.14

Data collection
Diffractometer	Bruker SMART APEX area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.859, 0.899
No. of measured, independent and observed [I > 2σ(I)] reflections	4588, 2335, 2176
R_int	0.026
(sin θ/λ)_max (Å⁻¹)	0.617

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.039, 0.106, 1.06
No. of reflections	2335
No. of parameters	172
No. of restraints	1
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.65, −0.49

Computer programs: SMART (Bruker, 2002), SAINT (Bruker, 2002), 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
N2—H2···O5ⁱ	0.86	1.83	2.670 (2)	166.2
O2—H2A···O3	0.863 (10)	1.593 (11)	2.452 (2)	173 (3)
O1W—H1W2···O1ⁱⁱ	0.85	1.91	2.7579 (19)	177.6
O1W—H1W1···O1ⁱⁱⁱ	0.85	2.03	2.847 (2)	160.0

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

Acknowledgements

We thank Hengyang Normal University for supporting this study.

References

Bruker (2002). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Gao, S., Zhang, X.-F., Huo, L.-H. & Zhao, H. (2004). Acta Cryst. E60, m1790–m1792. Web of Science CSD CrossRef IUCr Journals Google Scholar
Liu, C.-B., Nie, X.-L. & Wen, H.-L. (2007). Acta Cryst. E63, m2244. Web of Science CSD CrossRef IUCr Journals Google Scholar
Nie, X.-L., Wen, H.-L., Wu, Z.-S., Liu, D.-B. & Liu, C.-B. (2007). Acta Cryst. E63, m753–m755. Web of Science CSD CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (1996). 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
Shimizu, E., Kondo, M., Fuwa, Y., Sarker, R. P., Miyazawa, M., Ueno, M., Naito, T., Maeda, K. & Uchida, F. (2004). Inorg. Chem. Commun. 7, 1191–1194. Web of Science CSD CrossRef CAS Google Scholar
Zeng, J.-Z., Yi, X.-G., Lin, J.-Y., Ying, S.-M. & Huang, G.-S. (2008). Acta Cryst. E64, m476. Web of Science CSD CrossRef IUCr Journals Google Scholar
Zhang, M.-B., Chen, Y.-M., Zheng, S.-T. & Yang, G.-Y. (2006). Eur. J. Inorg. Chem. pp. 1423–1428. Web of Science CSD CrossRef Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.