catena-Poly[[diaqua­cobalt(II)]-μ2-7-oxa­bicyclo­[2.2.1]heptane-2,3-dicarboxyl­ato-κ4O2,O3,O7:O2′]

Zhang, F.; Lin, Q.-Y.; Wang, Y.-C.; He, J.-D.

doi:10.1107/S1600536812000554

metal-organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 68| Part 2| February 2012| Page m146

doi:10.1107/S1600536812000554

Open

access

catena-Poly[[diaquacobalt(II)]-μ₂-7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylato-κ⁴O²,O³,O⁷:O^2′]

Fan Zhang,^a,^b Qiu-Yue Lin,^a,^b ^* Yong-Chang Wang ^b and Ji-Du He ^b

^aZhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua, Zhejiang 321004, People's Republic of China, and ^bCollege of Chemistry and Life Science, Zhejiang Normal University, Jinhua 321004, Zhejiang, People's Republic of China
^*Correspondence e-mail: sky51@zjnu.cn

(Received 24 December 2011; accepted 6 January 2012; online 14 January 2012)

The polymeric title complex, [Co(C₈H₈O₅)(H₂O)₂]_n was synthesized by reaction of cobalt acetate with 7-oxabicyclo[2,2,1]heptane-2,3-dicarboxylic anhydride. The Co^II ion is six-coordinated in a distorted octahedral environment, binding to two water O atoms, to the ether O atom of the bicycloheptane unit, to two carboxylate O atoms from two different carboxylate groups of the same anion and to one carboxylate O atom from a symmetry-related anion. The bridging character of the dianion leads to the formation of ribbons along [001]. The ribbons are linked into a layered network parallel to (010) by several O—H⋯O hydrogen-bonding interactions involving the coordinating water molecules as donors and the carboxylate O atoms of neighbouring ribbons as acceptors. The crystal under investigation was an inversion twin.

Related literature

For background to the applications of norcantharidin [systematic name: 7-oxabicyclo(2.2.1)heptane-2,3-dicarboxylic anhydride], see: Yang et al. (2002 ). For the isotypic Cu analogue, see: Wang et al. (2009a ), and for a related Ni complex with monoclinic symmetry, see: Wang et al. (2009b ).

Experimental

Crystal data

[Co(C₈H₈O₅)(H₂O)₂]
M_r = 279.11
Orthorhombic, I b a 2
a = 10.3794 (10) Å
b = 18.983 (3) Å
c = 10.5021 (12) Å
V = 2069.3 (5) Å³
Z = 8
Mo Kα radiation
μ = 1.68 mm⁻¹
T = 296 K
0.22 × 0.15 × 0.10 mm

Data collection

Bruker APEXII area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2006 ) T_min = 0.742, T_max = 0.851
13174 measured reflections
1837 independent reflections
1821 reflections with I > 2σ(I)
R_int = 0.025

Refinement

R[F² > 2σ(F²)] = 0.029
wR(F²) = 0.088
S = 1.00
1837 reflections
146 parameters
7 restraints
H-atom parameters constrained
Δρ_max = 0.32 e Å⁻³
Δρ_min = −0.77 e Å⁻³
Absolute structure: Flack (1983 ), 860 Friedel pairs
Flack parameter: 0.12 (3)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1W—H1WA⋯O1ⁱ	0.85	1.98	2.832 (3)	180
O2W—H2WB⋯O4ⁱ	0.85	1.96	2.811 (3)	180
O1W—H1WB⋯O4ⁱⁱ	0.85	1.95	2.800 (3)	180
O2W—H2WA⋯O3ⁱⁱⁱ	0.85	1.86	2.708 (3)	180
Symmetry codes: (i) $[x, -y+2, z-{\script{1\over 2}}]$ ; (ii) $[-x, y, z-{\script{1\over 2}}]$ ; (iii) -x, -y+2, z.

Data collection: APEX2 (Bruker, 2006); cell refinement: SAINT (Bruker, 2006); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2006 ); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536812000554/wm2580sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536812000554/wm2580Isup2.hkl

checkCIF report

Comment top

7-oxabicyclo[2,2,1]heptane-2,3-dicarboxylic anhydride (norcantharidin), a traditional Chinese drug, has great anti-cancer activity. The coordination chemistry of cobalt has been important in biology mainly because of coenzyme B₁₂ (Yang et al., 2002). Therefore studying the combination of norcantharidin and cobalt seemed interesting. In this communication, the polymeric title complex, [Co(C₈H₈O₅)(H₂O)₂]_n is reported.

The isostructural cooper complex (Wang et al., 2009a) and a similar nickel complex with monoclinic symmetry (Wang et al., 2009b) of demethylcantharate have been reported previously. The coordination of the Co²⁺ ion in the title complex is shown in Fig. 1. The Co²⁺ ion is six-coordinated in a distorted octahedral coordination mode, binding to two water O atoms, to the bridging O atom of the bicycloheptane unit, to two carboxylate O atoms from different carboxylate groups and to one carboxylate O atom from a symmetry-related bridging anion. This leads to the formation of ribbons extending along [001] (Fig. 2).

As also shown in Fig. 2, the ribbons are linked into a two-dimensional network parallel to (010) by several O—H···O hydrogen-bonding interactions involving the coordinating water molecules as donors and the carboxylate O atoms of neighbouring ribbons as acceptors.

Related literature top

For background to the applications of norcantharidin [systematic name: 7-oxabicyclo(2.2.1)heptane-2,3-dicarboxylic anhydride], see: Yang et al. (2002). For the isotypic Cu analogue, see: Wang et al. (2009a), and for a related Ni complex with monoclinic symmetry, see: Wang et al. (2009b).

Experimental top

A mixture of 0.5 mmol norcantharidin, 0.5 mmol cobalt acetate and 15 mL distilled water was sealed in a 25 mL Teflon-lined stainless vessel and heated at 443 K for 3 d, then cooled slowly to room temperature. The solution was filtered and block red crystals were obtained.

Computing details top

Data collection: APEX2 (Bruker, 2006); cell refinement: SAINT (Bruker, 2006); data reduction: SAINT (Bruker, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2006); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. The coordination of the Co²⁺ ion with atom-labelling scheme and displacement ellipsoids drawn at the 30% probability level. [[Symmetry code (A) x, -y+2, z-1/2].
	Fig. 2. The one-dimensional polymeric structure of the title complex along [001] with hydrogen bonding interactions (dotted lines).

catena-Poly[[diaquacobalt(II)]-µ₂-7-oxabicyclo[2.2.1]heptane-2,3- dicarboxylato-κ⁴O²,O³,O⁷:O^2'] top

Crystal data top

[Co(C₈H₈O₅)(H₂O)₂]	F(000) = 1144
M_r = 279.11	D_x = 1.792 Mg m⁻³
Orthorhombic, Iba2	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: I 2 -2c	Cell parameters from 9954 reflections
a = 10.3794 (10) Å	θ = 2.2–25.0°
b = 18.983 (3) Å	µ = 1.68 mm⁻¹
c = 10.5021 (12) Å	T = 296 K
V = 2069.3 (5) Å³	Block, red
Z = 8	0.22 × 0.15 × 0.10 mm

Data collection top

Bruker APEXII area-detector diffractometer	1837 independent reflections
Radiation source: fine-focus sealed tube	1821 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.025
ω scans	θ_max = 25.0°, θ_min = 2.2°
Absorption correction: multi-scan (SADABS; Bruker, 2006)	h = −12→9
T_min = 0.742, T_max = 0.851	k = −22→22
13174 measured reflections	l = −12→12

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)] = 0.029	H-atom parameters constrained
wR(F²) = 0.088	w = 1/[σ²(F_o²) + (0.0734P)² + 1.6545P] where P = (F_o² + 2F_c²)/3
S = 1.00	(Δ/σ)_max = 0.001
1837 reflections	Δρ_max = 0.32 e Å⁻³
146 parameters	Δρ_min = −0.77 e Å⁻³
7 restraints	Absolute structure: Flack (1983), 860 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.12 (3)

Crystal data top

[Co(C₈H₈O₅)(H₂O)₂]	V = 2069.3 (5) Å³
M_r = 279.11	Z = 8
Orthorhombic, Iba2	Mo Kα radiation
a = 10.3794 (10) Å	µ = 1.68 mm⁻¹
b = 18.983 (3) Å	T = 296 K
c = 10.5021 (12) Å	0.22 × 0.15 × 0.10 mm

Data collection top

Bruker APEXII area-detector diffractometer	1837 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2006)	1821 reflections with I > 2σ(I)
T_min = 0.742, T_max = 0.851	R_int = 0.025
13174 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.029	H-atom parameters constrained
wR(F²) = 0.088	Δρ_max = 0.32 e Å⁻³
S = 1.00	Δρ_min = −0.77 e Å⁻³
1837 reflections	Absolute structure: Flack (1983), 860 Friedel pairs
146 parameters	Absolute structure parameter: 0.12 (3)
7 restraints

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	0.23966 (4)	0.966647 (19)	0.74932 (8)	0.02813 (16)
O1W	0.1588 (3)	0.91672 (15)	0.5806 (2)	0.0429 (6)
H1WA	0.2080	0.9431	0.5369	0.064*
H1WB	0.0843	0.8987	0.5727	0.064*
O1	0.3221 (2)	0.99510 (11)	0.9348 (2)	0.0248 (4)
O2W	0.1226 (2)	1.06142 (12)	0.7759 (2)	0.0374 (6)
H2WA	0.0483	1.0731	0.8026	0.056*
H2WB	0.1121	1.0858	0.7089	0.056*
O2	0.3530 (2)	0.96635 (11)	1.1378 (2)	0.0257 (5)
O3	0.1138 (2)	0.90091 (11)	0.8609 (2)	0.0303 (5)
O4	0.0868 (2)	0.85747 (12)	1.0548 (2)	0.0309 (5)
O5	0.37724 (17)	0.87420 (9)	0.76172 (19)	0.0215 (4)
C1	0.4783 (3)	0.87921 (15)	0.8584 (3)	0.0242 (6)
H1	0.5346	0.9202	0.8480	0.029*
C2	0.4010 (3)	0.87971 (14)	0.9824 (3)	0.0201 (6)
H2	0.4522	0.8587	1.0510	0.024*
C3	0.2838 (3)	0.82969 (15)	0.9480 (3)	0.0217 (6)
H3	0.2852	0.7878	1.0023	0.026*
C4	0.3196 (3)	0.80965 (14)	0.8104 (3)	0.0258 (6)
H4	0.2465	0.7927	0.7597	0.031*
C5	0.4367 (4)	0.75899 (17)	0.8103 (4)	0.0389 (8)
H5A	0.4272	0.7223	0.8738	0.047*
H5B	0.4492	0.7376	0.7273	0.047*
C6	0.5475 (3)	0.80918 (18)	0.8437 (3)	0.0351 (7)
H6A	0.5895	0.7953	0.9224	0.042*
H6B	0.6110	0.8110	0.7760	0.042*
C7	0.3557 (2)	0.95301 (15)	1.0216 (3)	0.0179 (6)
C8	0.1514 (3)	0.86588 (14)	0.9561 (3)	0.0211 (6)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Co1	0.0293 (2)	0.0306 (3)	0.0245 (2)	−0.00025 (14)	0.0007 (2)	0.0048 (2)
O1W	0.0397 (14)	0.0645 (17)	0.0247 (11)	−0.0249 (12)	−0.0039 (11)	0.0043 (12)
O1	0.0329 (11)	0.0223 (10)	0.0191 (9)	0.0030 (8)	0.0000 (9)	0.0004 (8)
O2W	0.0309 (12)	0.0419 (12)	0.0394 (14)	0.0150 (10)	0.0098 (10)	0.0125 (10)
O2	0.0236 (12)	0.0331 (10)	0.0203 (10)	0.0057 (8)	−0.0002 (9)	−0.0052 (7)
O3	0.0186 (10)	0.0394 (12)	0.0329 (12)	0.0013 (9)	0.0023 (9)	0.0144 (10)
O4	0.0272 (11)	0.0399 (12)	0.0257 (11)	0.0020 (9)	0.0057 (9)	0.0035 (9)
O5	0.0231 (9)	0.0226 (9)	0.0187 (10)	0.0008 (7)	0.0006 (8)	−0.0003 (8)
C1	0.0195 (13)	0.0282 (14)	0.0249 (15)	0.0029 (11)	0.0012 (12)	−0.0046 (11)
C2	0.0196 (13)	0.0224 (14)	0.0183 (13)	0.0023 (11)	−0.0012 (11)	−0.0008 (11)
C3	0.0240 (13)	0.0184 (13)	0.0227 (14)	−0.0009 (12)	−0.0005 (12)	0.0036 (11)
C4	0.0310 (16)	0.0205 (13)	0.0259 (14)	−0.0007 (11)	−0.0011 (13)	−0.0034 (11)
C5	0.051 (2)	0.0250 (15)	0.0408 (18)	0.0140 (14)	0.0077 (17)	−0.0045 (13)
C6	0.0303 (16)	0.0438 (17)	0.0312 (17)	0.0170 (14)	0.0038 (15)	−0.0048 (14)
C7	0.0125 (12)	0.0237 (13)	0.0174 (14)	−0.0020 (10)	−0.0001 (11)	−0.0046 (11)
C8	0.0200 (14)	0.0196 (13)	0.0238 (14)	−0.0038 (10)	−0.0011 (12)	−0.0001 (11)

Geometric parameters (Å, º) top

Co1—O2ⁱ	2.091 (2)	C1—C6	1.519 (4)
Co1—O3	2.154 (2)	C1—C2	1.529 (4)
Co1—O1W	2.178 (3)	C1—H1	0.9800
Co1—O2W	2.188 (2)	C2—C7	1.525 (4)
Co1—O1	2.194 (2)	C2—C3	1.585 (4)
Co1—O5	2.2664 (18)	C2—H2	0.9800
O1W—H1WA	0.8500	C3—C8	1.539 (4)
O1W—H1WB	0.8500	C3—C4	1.540 (4)
O1—C7	1.262 (4)	C3—H3	0.9800
O2W—H2WA	0.8501	C4—C5	1.550 (4)
O2W—H2WB	0.8499	C4—H4	0.9800
O2—C7	1.246 (4)	C5—C6	1.534 (5)
O2—Co1ⁱⁱ	2.091 (2)	C5—H5A	0.9700
O3—C8	1.262 (4)	C5—H5B	0.9700
O4—C8	1.244 (4)	C6—H6A	0.9700
O5—C4	1.456 (3)	C6—H6B	0.9700
O5—C1	1.462 (4)

O2ⁱ—Co1—O3	176.84 (9)	C1—C2—C3	101.8 (2)
O2ⁱ—Co1—O1W	91.46 (10)	C7—C2—H2	109.9
O3—Co1—O1W	87.54 (10)	C1—C2—H2	109.9
O2ⁱ—Co1—O2W	83.31 (9)	C3—C2—H2	109.9
O3—Co1—O2W	94.03 (8)	C8—C3—C4	112.2 (2)
O1W—Co1—O2W	104.34 (11)	C8—C3—C2	113.9 (2)
O2ⁱ—Co1—O1	97.37 (9)	C4—C3—C2	100.2 (2)
O3—Co1—O1	84.03 (9)	C8—C3—H3	110.0
O1W—Co1—O1	168.35 (9)	C4—C3—H3	110.0
O2W—Co1—O1	84.31 (9)	C2—C3—H3	110.0
O2ⁱ—Co1—O5	98.56 (8)	O5—C4—C3	102.7 (2)
O3—Co1—O5	84.39 (7)	O5—C4—C5	101.5 (2)
O1W—Co1—O5	87.28 (10)	C3—C4—C5	110.1 (2)
O2W—Co1—O5	168.22 (10)	O5—C4—H4	113.8
O1—Co1—O5	83.92 (8)	C3—C4—H4	113.8
Co1—O1W—H1WA	87.2	C5—C4—H4	113.8
Co1—O1W—H1WB	127.2	C6—C5—C4	101.7 (2)
H1WA—O1W—H1WB	137.0	C6—C5—H5A	111.4
C7—O1—Co1	126.40 (17)	C4—C5—H5A	111.4
Co1—O2W—H2WA	139.4	C6—C5—H5B	111.4
Co1—O2W—H2WB	114.5	C4—C5—H5B	111.4
H2WA—O2W—H2WB	90.8	H5A—C5—H5B	109.3
C7—O2—Co1ⁱⁱ	133.2 (2)	C1—C6—C5	102.2 (3)
C8—O3—Co1	123.30 (19)	C1—C6—H6A	111.3
C4—O5—C1	96.1 (2)	C5—C6—H6A	111.3
C4—O5—Co1	114.38 (16)	C1—C6—H6B	111.3
C1—O5—Co1	116.19 (14)	C5—C6—H6B	111.3
O5—C1—C6	102.2 (2)	H6A—C6—H6B	109.2
O5—C1—C2	102.4 (2)	O2—C7—O1	124.9 (3)
C6—C1—C2	109.8 (2)	O2—C7—C2	117.2 (2)
O5—C1—H1	113.7	O1—C7—C2	117.9 (2)
C6—C1—H1	113.7	O4—C8—O3	124.1 (3)
C2—C1—H1	113.7	O4—C8—C3	118.0 (3)
C7—C2—C1	113.4 (2)	O3—C8—C3	117.8 (3)
C7—C2—C3	111.8 (2)

O2ⁱ—Co1—O1—C7	−134.4 (2)	C7—C2—C3—C4	122.2 (2)
O3—Co1—O1—C7	48.5 (2)	C1—C2—C3—C4	0.9 (3)
O1W—Co1—O1—C7	4.6 (6)	C1—O5—C4—C3	57.7 (2)
O2W—Co1—O1—C7	143.1 (2)	Co1—O5—C4—C3	−64.7 (2)
O5—Co1—O1—C7	−36.5 (2)	C1—O5—C4—C5	−56.1 (2)
O1W—Co1—O3—C8	131.9 (2)	Co1—O5—C4—C5	−178.54 (17)
O2W—Co1—O3—C8	−123.9 (2)	C8—C3—C4—O5	85.4 (3)
O1—Co1—O3—C8	−40.0 (2)	C2—C3—C4—O5	−35.8 (3)
O5—Co1—O3—C8	44.4 (2)	C8—C3—C4—C5	−167.1 (2)
O2ⁱ—Co1—O5—C4	−167.10 (18)	C2—C3—C4—C5	71.7 (3)
O3—Co1—O5—C4	11.75 (19)	O5—C4—C5—C6	34.5 (3)
O1W—Co1—O5—C4	−76.03 (19)	C3—C4—C5—C6	−73.8 (3)
O2W—Co1—O5—C4	94.6 (4)	O5—C1—C6—C5	−35.0 (3)
O1—Co1—O5—C4	96.32 (19)	C2—C1—C6—C5	73.2 (3)
O2ⁱ—Co1—O5—C1	82.24 (18)	C4—C5—C6—C1	0.3 (3)
O3—Co1—O5—C1	−98.90 (18)	Co1ⁱⁱ—O2—C7—O1	27.9 (4)
O1W—Co1—O5—C1	173.31 (19)	Co1ⁱⁱ—O2—C7—C2	−151.0 (2)
O2W—Co1—O5—C1	−16.1 (5)	Co1—O1—C7—O2	−149.7 (2)
O1—Co1—O5—C1	−14.33 (18)	Co1—O1—C7—C2	29.1 (3)
C4—O5—C1—C6	57.0 (3)	C1—C2—C7—O2	−144.6 (3)
Co1—O5—C1—C6	178.01 (18)	C3—C2—C7—O2	101.0 (3)
C4—O5—C1—C2	−56.8 (2)	C1—C2—C7—O1	36.5 (3)
Co1—O5—C1—C2	64.2 (2)	C3—C2—C7—O1	−77.9 (3)
O5—C1—C2—C7	−86.2 (3)	Co1—O3—C8—O4	142.1 (2)
C6—C1—C2—C7	165.7 (2)	Co1—O3—C8—C3	−39.6 (3)
O5—C1—C2—C3	34.1 (3)	C4—C3—C8—O4	149.2 (3)
C6—C1—C2—C3	−74.0 (3)	C2—C3—C8—O4	−97.8 (3)
C7—C2—C3—C8	2.2 (3)	C4—C3—C8—O3	−29.2 (3)
C1—C2—C3—C8	−119.1 (2)	C2—C3—C8—O3	83.8 (3)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H1WA···O1ⁱ	0.85	1.98	2.832 (3)	180
O2W—H2WB···O4ⁱ	0.85	1.96	2.811 (3)	180
O1W—H1WB···O4ⁱⁱⁱ	0.85	1.95	2.800 (3)	180
O2W—H2WA···O3^iv	0.85	1.86	2.708 (3)	180

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

Experimental details

Crystal data
Chemical formula	[Co(C₈H₈O₅)(H₂O)₂]
M_r	279.11
Crystal system, space group	Orthorhombic, Iba2
Temperature (K)	296
a, b, c (Å)	10.3794 (10), 18.983 (3), 10.5021 (12)
V (Å³)	2069.3 (5)
Z	8
Radiation type	Mo Kα
µ (mm⁻¹)	1.68
Crystal size (mm)	0.22 × 0.15 × 0.10

Data collection
Diffractometer	Bruker APEXII area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2006)
T_min, T_max	0.742, 0.851
No. of measured, independent and observed [I > 2σ(I)] reflections	13174, 1837, 1821
R_int	0.025
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.029, 0.088, 1.00
No. of reflections	1837
No. of parameters	146
No. of restraints	7
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.32, −0.77
Absolute structure	Flack (1983), 860 Friedel pairs
Absolute structure parameter	0.12 (3)

Computer programs: APEX2 (Bruker, 2006), SAINT (Bruker, 2006), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg, 2006).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H1WA···O1ⁱ	0.85	1.98	2.832 (3)	179.7
O2W—H2WB···O4ⁱ	0.85	1.96	2.811 (3)	179.6
O1W—H1WB···O4ⁱⁱ	0.85	1.95	2.800 (3)	179.9
O2W—H2WA···O3ⁱⁱⁱ	0.85	1.86	2.708 (3)	179.6

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

Acknowledgements

The authors thank the Natural Science Foundation of Zhejiang Province, China (grant No. Y407301) for financial support.

References

Brandenburg, K. (2006). DIAMOND. Crystal Impact GbR, Bonn, Germany. Google Scholar
Bruker (2006). APEX2, SADABS and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Flack, H. D. (1983). Acta Cryst. A39, 876–881. CrossRef CAS Web of Science IUCr Journals Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Wang, Y.-Y., Hu, R.-D. & Wang, Y.-J. (2009a). Acta Cryst. E65, m169. Web of Science CSD CrossRef IUCr Journals Google Scholar
Wang, Y.-Y., Hu, R.-D., Zhu, W.-Z. & Lin, Q.-Y. (2009b). Acta Cryst. E65, m787. Web of Science CSD CrossRef IUCr Journals Google Scholar
Yang, L.-Q., Crans, D. C., Miller, S. M., Cour, A., Anderson, O. P., Kaszynski, P. M., Godzala, M. E., Austin, L. D. & Willsky, G. R. (2002). Inorg. Chem. 41, 4859–4871. Web of Science CSD CrossRef PubMed CAS 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.