Poly[[tetra-μ2-aqua-diaqua-μ6-oxalato-barium(II)] 2,4,6-trinitro­phenolate monohydrate]

Hong, P.-Z.; Song, W.-D.; Wu, Z.-H.

doi:10.1107/S1600536807038159

Poly[[tetra-μ₂-aqua-diaqua-μ₆-oxalato-barium(II)] 2,4,6-trinitrophenolate monohydrate]

In the title coordination polymer, {[Ba(C₂O₄)(H₂O)₆]C₆H₂N₃O₇·H₂O}_n, each Ba^II ion is nine-coordinated by three O atoms from two oxalate ligands, two O atoms from two water molecules and four O atoms from μ₂-bridging aqua ligands, and displays a distorted tricapped trigonal–prismatic geometry. The μ₆-bridging oxalate ligands and μ₂-aqua ligands link Ba^II ions to form a neutral layer. The coordinated water molecules link the 2,4,6-trinitrophenolate anions to form a supramolecular network via hydrogen-bonding interactions.

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Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807038159/lx2010sup1.cif Contains datablocks I, global
	Structure factor file (CIF format) https://doi.org/10.1107/S1600536807038159/lx2010Isup2.hkl Contains datablock I

CCDC reference: 660070

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Key indicators

Single-crystal X-ray study
T = 293 K
Mean (C-C) = 0.004 Å
R factor = 0.024
wR factor = 0.056
Data-to-parameter ratio = 14.3

checkCIF/PLATON results

No syntax errors found





Alert level B
PLAT369_ALERT_2_B Long   C(sp2)-C(sp2) Bond  C7     -   C7_d   ...       1.57 Ang.

Alert level C
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         N1
PLAT245_ALERT_2_C U(iso) H4WA    Smaller than U(eq) O4W     by ...       0.02 AngSq
PLAT245_ALERT_2_C U(iso) H4WB    Smaller than U(eq) O4W     by ...       0.02 AngSq
PLAT245_ALERT_2_C U(iso) H5WA    Smaller than U(eq) O5W     by ...       0.01 AngSq
PLAT245_ALERT_2_C U(iso) H5WB    Smaller than U(eq) O5W     by ...       0.01 AngSq
PLAT245_ALERT_2_C U(iso) H1WA    Smaller than U(eq) O1W     by ...       0.02 AngSq
PLAT245_ALERT_2_C U(iso) H1WB    Smaller than U(eq) O1W     by ...       0.02 AngSq
PLAT720_ALERT_4_C Number of Unusual/Non-Standard Label(s) ........         10
PLAT764_ALERT_4_C Overcomplete CIF Bond List Detected (Rep/Expd) .       1.11 Ratio

Alert level G
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature .        293 K
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......         14

   0 ALERT level A = In general: serious problem
   1 ALERT level B = Potentially serious problem
   9 ALERT level C = Check and explain
   3 ALERT level G = General alerts; check

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   8 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

Comment top

2,4,6-trinitrophenolic acid have afforded a large number of O-chelated metal derivates, such as barium (Pierce-Butler, 1982), potassium (Li, et al. 2003), sodium (Ward, et al., 1984) and so on.

As illustrated in Fig. 1, in the asymmetric unit of (I) each Ba^II centre is nine-coordinated by three carboxyl O atoms from two oxalato ligands, two O atoms from two water molecules and four O atoms from /m₂ bridging aqua ligands, and displaying a distorted tricapped trigonal prism geometry. All geometries are general. Via a Ba···Ba interaction between symmetrically related moieties the compound forms polymer structures with a Ba···Ba separation of 6.957 (3) Å that are further extended to a supramolecular network through intermolecular hydrogen bonding interaction among the cationic units, 2,4,6-trinitrophenolate anions and uncoordinated molecules (Table 1 and Fig. 2).

Related literature top

For related literature, see: Li et al. (2003); Pierce-Butler (1982); Ward et al. (1984).

Experimental top

The title complex was prepared by the addition of a stoichiometric amount of barium chloride (4.16 g, 20 mmol) and oxalic acid (1.80 g, 20 mmol) to a hot aqueous solution (25 ml) of 2,4,6-trinitrophenolic acid (4.58 g, 30 mmol). The pH was then adjusted to 7.0 to 8.0 with NaOH (1.2 g, 30 mmol). The resulting solution was filtered, and yellow crystals were obtained at room temperature on slow evaporation of the solvent over several days.

Structure description top

2,4,6-trinitrophenolic acid have afforded a large number of O-chelated metal derivates, such as barium (Pierce-Butler, 1982), potassium (Li, et al. 2003), sodium (Ward, et al., 1984) and so on.

For related literature, see: Li et al. (2003); Pierce-Butler (1982); Ward et al. (1984).

Computing details top

Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 2004); software used to prepare material for publication: SHELXTL (Bruker, 1997).

Figures top

	Fig. 1. The structure of (I), with displacement ellipsoids drawn at the 30% probability level for non-H atoms. [Symmetry codes:(i)-x, 1 - y, -z; (ii) -x, -y, -z; (iii) -x, y + 1/2, 1/2 - z; (iv) -x, y - 1/2, 1/2 - z.]
	Fig. 2. The unit-cell packing diagram of (I). Hydrogen bonds are shown as dashed lines.

Poly[[di-µ₂-aqua-diaqua-hemi-µ₆-oxalato-barium(II)] 2,4,6-trinitrophenolate monohydrate] top

Crystal data top

[Ba(C₂O₄)_0.5(H₂O)₄]C₆H₂N₃O₇·H₂O	F(000) = 972
M_r = 499.54	D_x = 2.180 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -p_2ybc	Cell parameters from 3600 reflections
a = 15.1489 (2) Å	θ = 1.7–28.0°
b = 6.5736 (1) Å	µ = 2.70 mm⁻¹
c = 15.3111 (2) Å	T = 293 K
β = 93.557 (1)°	Block, yellow
V = 1521.78 (4) Å³	0.19 × 0.18 × 0.16 mm
Z = 4

Data collection top

Bruker APEXII area-detector diffractometer	3654 independent reflections
Radiation source: fine-focus sealed tube	3126 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.028
φ and ω scans	θ_max = 28.0°, θ_min = 2.7°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −20→19
T_min = 0.608, T_max = 0.650	k = −8→8
13176 measured reflections	l = −20→16

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)] = 0.024	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.056	H atoms treated by a mixture of independent and constrained refinement
S = 1.03	w = 1/[σ²(F_o²) + (0.0277P)² + 0.4903P] where P = (F_o² + 2F_c²)/3
3654 reflections	(Δ/σ)_max < 0.001
256 parameters	Δρ_max = 0.57 e Å⁻³
14 restraints	Δρ_min = −0.53 e Å⁻³

Crystal data top

[Ba(C₂O₄)_0.5(H₂O)₄]C₆H₂N₃O₇·H₂O	V = 1521.78 (4) Å³
M_r = 499.54	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 15.1489 (2) Å	µ = 2.70 mm⁻¹
b = 6.5736 (1) Å	T = 293 K
c = 15.3111 (2) Å	0.19 × 0.18 × 0.16 mm
β = 93.557 (1)°

Data collection top

Bruker APEXII area-detector diffractometer	3654 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	3126 reflections with I > 2σ(I)
T_min = 0.608, T_max = 0.650	R_int = 0.028
13176 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.024	14 restraints
wR(F²) = 0.056	H atoms treated by a mixture of independent and constrained refinement
S = 1.03	Δρ_max = 0.57 e Å⁻³
3654 reflections	Δρ_min = −0.53 e Å⁻³
256 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
Ba	0.009199 (10)	0.090317 (19)	0.144062 (9)	0.02169 (6)
C1	0.53089 (19)	0.0665 (4)	0.32517 (18)	0.0287 (6)
H1	0.5152	0.0558	0.3828	0.034*
C2	0.61794 (18)	0.0706 (4)	0.30611 (17)	0.0272 (6)
C3	0.64955 (18)	0.0795 (4)	0.21936 (17)	0.0264 (6)
C4	0.57696 (19)	0.0866 (4)	0.15341 (17)	0.0286 (6)
C5	0.48959 (19)	0.0906 (4)	0.17056 (18)	0.0291 (6)
H5	0.4462	0.1012	0.1251	0.035*
C6	0.46645 (18)	0.0786 (4)	0.25682 (18)	0.0266 (6)
C7	−0.00848 (17)	0.4258 (3)	−0.03987 (16)	0.0215 (5)
H1WA	0.182 (2)	−0.021 (3)	0.4331 (19)	0.026*
H1WB	0.2387 (13)	0.113 (4)	0.4163 (19)	0.026*
H2WA	0.0900 (16)	−0.317 (4)	0.1881 (15)	0.026*
H2WB	0.1540 (11)	−0.240 (4)	0.2382 (17)	0.026*
H3WA	0.1313 (16)	0.224 (4)	0.3221 (14)	0.026*
H3WB	0.1543 (15)	0.353 (4)	0.2658 (17)	0.026*
H4WA	0.2140 (16)	0.102 (4)	0.1052 (16)	0.026*
H4WB	0.1765 (18)	0.208 (3)	0.0395 (15)	0.026*
H5WA	−0.2039 (15)	0.144 (4)	0.1023 (15)	0.026*
H5WB	−0.1725 (18)	0.123 (4)	0.0273 (12)	0.026*
N1	0.68199 (17)	0.0555 (4)	0.38123 (16)	0.0374 (6)
N2	0.37473 (16)	0.0789 (3)	0.27700 (17)	0.0349 (6)
N3	0.59676 (18)	0.0979 (4)	0.06088 (16)	0.0386 (6)
O1	0.73001 (13)	0.0796 (3)	0.20391 (13)	0.0393 (5)
O2	0.75026 (17)	0.1514 (5)	0.38100 (16)	0.0711 (8)
O3	0.66196 (17)	−0.0536 (4)	0.44163 (15)	0.0607 (7)
O4	0.35790 (16)	0.0651 (4)	0.35365 (16)	0.0553 (7)
O5	0.31768 (15)	0.0929 (4)	0.21685 (17)	0.0556 (7)
O6	0.54645 (17)	0.1997 (4)	0.01244 (15)	0.0593 (7)
O7	0.65884 (16)	0.0004 (5)	0.03584 (15)	0.0611 (7)
O8	−0.00452 (12)	0.2386 (2)	−0.02508 (10)	0.0256 (4)
O9	0.02537 (13)	0.4939 (3)	0.11302 (11)	0.0311 (4)
O1W	0.18547 (15)	0.1042 (4)	0.42656 (16)	0.0439 (5)
O2W	0.10105 (13)	−0.2370 (3)	0.22765 (12)	0.0294 (4)
O3W	0.11131 (13)	0.2932 (3)	0.28179 (13)	0.0322 (4)
O4W	0.17396 (15)	0.1144 (3)	0.07199 (16)	0.0432 (5)
O5W	−0.16202 (14)	0.1761 (4)	0.07469 (14)	0.0397 (5)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Ba	0.02843 (10)	0.01617 (8)	0.02048 (9)	0.00071 (6)	0.00166 (6)	0.00054 (5)
C1	0.0330 (16)	0.0297 (13)	0.0233 (13)	0.0002 (11)	0.0024 (11)	0.0015 (10)
C2	0.0257 (14)	0.0299 (13)	0.0256 (13)	−0.0018 (11)	−0.0009 (11)	0.0010 (10)
C3	0.0251 (14)	0.0293 (13)	0.0251 (13)	−0.0010 (11)	0.0024 (11)	0.0016 (10)
C4	0.0313 (15)	0.0329 (14)	0.0218 (13)	−0.0024 (11)	0.0033 (11)	0.0007 (10)
C5	0.0278 (15)	0.0323 (14)	0.0266 (13)	−0.0010 (11)	−0.0040 (11)	0.0004 (11)
C6	0.0232 (14)	0.0258 (13)	0.0311 (14)	0.0010 (11)	0.0039 (11)	0.0021 (10)
C7	0.0238 (13)	0.0196 (12)	0.0210 (12)	−0.0016 (10)	0.0005 (10)	0.0006 (9)
N1	0.0300 (14)	0.0570 (16)	0.0251 (12)	0.0012 (12)	0.0001 (10)	0.0040 (11)
N2	0.0250 (13)	0.0368 (13)	0.0430 (15)	0.0013 (10)	0.0034 (11)	0.0021 (10)
N3	0.0366 (15)	0.0548 (16)	0.0241 (12)	−0.0148 (13)	0.0011 (11)	−0.0023 (11)
O1	0.0242 (11)	0.0616 (14)	0.0322 (11)	−0.0026 (10)	0.0033 (9)	0.0011 (9)
O2	0.0423 (15)	0.128 (2)	0.0418 (14)	−0.0344 (16)	−0.0089 (12)	0.0092 (15)
O3	0.0463 (15)	0.097 (2)	0.0383 (13)	−0.0038 (13)	−0.0067 (11)	0.0281 (13)
O4	0.0367 (14)	0.0888 (19)	0.0424 (14)	0.0053 (12)	0.0174 (11)	0.0069 (12)
O5	0.0272 (12)	0.0817 (19)	0.0568 (15)	0.0000 (11)	−0.0067 (11)	0.0038 (12)
O6	0.0700 (18)	0.0735 (17)	0.0332 (12)	−0.0032 (14)	−0.0053 (12)	0.0162 (12)
O7	0.0420 (15)	0.107 (2)	0.0355 (13)	0.0007 (15)	0.0117 (11)	−0.0187 (14)
O8	0.0371 (11)	0.0156 (8)	0.0241 (9)	−0.0007 (8)	0.0018 (8)	−0.0003 (6)
O9	0.0480 (13)	0.0202 (9)	0.0241 (9)	−0.0037 (8)	−0.0060 (8)	0.0018 (7)
O1W	0.0266 (12)	0.0562 (14)	0.0490 (13)	0.0089 (11)	0.0037 (10)	0.0072 (11)
O2W	0.0300 (11)	0.0311 (10)	0.0269 (10)	0.0046 (9)	−0.0011 (8)	−0.0014 (8)
O3W	0.0325 (12)	0.0333 (11)	0.0304 (10)	−0.0008 (9)	−0.0016 (9)	0.0039 (8)
O4W	0.0305 (12)	0.0545 (14)	0.0440 (14)	0.0009 (10)	−0.0018 (10)	0.0108 (10)
O5W	0.0306 (12)	0.0619 (14)	0.0270 (11)	−0.0074 (11)	0.0042 (9)	−0.0005 (10)

Geometric parameters (Å, º) top

Ba—O9	2.709 (2)	C5—C6	1.390 (4)
Ba—O8	2.763 (2)	C5—H5	0.9300
Ba—O4W	2.795 (2)	C6—N2	1.442 (4)
Ba—O5W	2.799 (2)	C7—O9^iv	1.250 (3)
Ba—O2W	2.825 (2)	C7—O8	1.252 (3)
Ba—O8ⁱ	2.826 (2)	C7—C7^iv	1.571 (5)
Ba—O3W	2.866 (2)	N1—O2	1.212 (3)
Ba—O2Wⁱⁱ	2.888 (2)	N1—O3	1.223 (3)
Ba—O3Wⁱⁱⁱ	2.949 (2)	N2—O4	1.220 (3)
Ba—Ba	6.957 (3)	N2—O5	1.227 (3)
Ba—Baⁱ	4.5603 (3)	N3—O7	1.219 (3)
Ba—Baⁱⁱ	4.6386 (2)	N3—O6	1.228 (3)
Ba—Baⁱⁱⁱ	4.6386 (2)	O1W—H1WA	0.832 (17)
C1—C2	1.368 (4)	O1W—H1WB	0.834 (17)
C1—C6	1.388 (4)	O2W—H2WA	0.810 (16)
C1—H1	0.9300	O2W—H2WB	0.809 (16)
C2—C3	1.441 (4)	O3W—H3WA	0.808 (16)
C2—N1	1.461 (3)	O3W—H3WB	0.813 (16)
C3—O1	1.256 (3)	O4W—H4WA	0.771 (16)
C3—C4	1.447 (4)	O4W—H4WB	0.796 (16)
C4—C5	1.366 (4)	O5W—H5WA	0.812 (16)
C4—N3	1.468 (4)	O5W—H5WB	0.812 (16)

O9—Ba—O8	59.49 (5)	O3W—Ba—O3Wⁱⁱⁱ	110.10 (3)
O9—Ba—O4W	77.44 (6)	O2Wⁱⁱ—Ba—O3Wⁱⁱⁱ	66.46 (5)
O8—Ba—O4W	68.10 (6)	C2—C1—C6	118.7 (3)
O9—Ba—O5W	80.09 (6)	C1—C2—C3	125.3 (2)
O8—Ba—O5W	63.84 (6)	C1—C2—N1	115.6 (2)
O4W—Ba—O5W	131.91 (6)	C3—C2—N1	119.1 (2)
O9—Ba—O2W	141.07 (6)	O1—C3—C2	123.7 (2)
O8—Ba—O2W	134.40 (5)	O1—C3—C4	125.0 (3)
O4W—Ba—O2W	78.19 (6)	C2—C3—C4	111.3 (2)
O5W—Ba—O2W	138.08 (6)	C5—C4—C3	124.8 (3)
O9—Ba—O8ⁱ	129.44 (5)	C5—C4—N3	116.3 (2)
O8—Ba—O8ⁱ	70.63 (5)	C3—C4—N3	118.9 (3)
O4W—Ba—O8ⁱ	77.07 (6)	C4—C5—C6	119.1 (2)
O5W—Ba—O8ⁱ	85.63 (6)	C1—C6—C5	120.8 (3)
O2W—Ba—O8ⁱ	72.61 (5)	C1—C6—N2	118.7 (3)
O9—Ba—O3W	67.85 (5)	C5—C6—N2	120.5 (2)
O8—Ba—O3W	122.09 (5)	O9^iv—C7—O8	125.6 (2)
O4W—Ba—O3W	79.03 (6)	O9^iv—C7—C7^iv	116.6 (2)
O5W—Ba—O3W	129.11 (6)	O8—C7—C7^iv	117.8 (2)
O2W—Ba—O3W	78.05 (5)	O2—N1—O3	124.0 (3)
O8ⁱ—Ba—O3W	145.21 (5)	O2—N1—C2	119.2 (2)
O9—Ba—O2Wⁱⁱ	78.28 (6)	O3—N1—C2	116.8 (2)
O8—Ba—O2Wⁱⁱ	119.06 (5)	O4—N2—O5	123.2 (3)
O4W—Ba—O2Wⁱⁱ	144.51 (6)	O4—N2—C6	117.9 (2)
O5W—Ba—O2Wⁱⁱ	67.51 (6)	O5—N2—C6	118.9 (3)
O2W—Ba—O2Wⁱⁱ	106.29 (4)	O7—N3—O6	123.9 (3)
O8ⁱ—Ba—O2Wⁱⁱ	138.31 (5)	O7—N3—C4	119.0 (3)
O3W—Ba—O2Wⁱⁱ	67.99 (5)	O6—N3—C4	117.0 (3)
O9—Ba—O3Wⁱⁱⁱ	141.37 (6)	H1WA—O1W—H1WB	99 (3)
O8—Ba—O3Wⁱⁱⁱ	125.61 (5)	H2WA—O2W—H2WB	107 (2)
O4W—Ba—O3Wⁱⁱⁱ	141.16 (6)	H3WA—O3W—H3WB	104 (2)
O5W—Ba—O3Wⁱⁱⁱ	72.43 (6)	H4WA—O4W—H4WB	116 (2)
O2W—Ba—O3Wⁱⁱⁱ	67.69 (6)	H5WA—O5W—H5WB	104 (2)
O8ⁱ—Ba—O3Wⁱⁱⁱ	75.52 (5)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H1WB···O4	0.83 (2)	2.12 (2)	2.915 (3)	159 (3)
O1W—H1WA···O5Wⁱⁱⁱ	0.83 (2)	2.02 (2)	2.837 (3)	169 (3)
O2W—H2WB···O1^v	0.81 (2)	2.25 (2)	2.961 (3)	146 (3)
O2W—H2WB···O2^v	0.81 (2)	2.50 (3)	2.974 (3)	118 (2)
O2W—H2WA···O9^vi	0.81 (2)	1.92 (2)	2.697 (3)	160 (3)
O3W—H3WB···O1^vii	0.81 (2)	2.32 (2)	3.051 (3)	149 (3)
O3W—H3WA···O1W	0.81 (2)	1.92 (2)	2.722 (3)	170 (3)
O4W—H4WA···O5	0.77 (2)	2.25 (2)	3.013 (3)	171 (3)
O4W—H4WB···O1W^viii	0.80 (2)	2.13 (2)	2.908 (3)	164 (3)
O5W—H5WA···O1^ix	0.81 (2)	1.95 (2)	2.719 (3)	158 (3)
O5W—H5WA···O7^ix	0.81 (2)	2.45 (2)	2.975 (3)	124 (2)
O5W—H5WB···O4Wⁱ	0.81 (2)	2.18 (2)	2.945 (3)	158 (3)

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

Experimental details

Crystal data
Chemical formula	[Ba(C₂O₄)_0.5(H₂O)₄]C₆H₂N₃O₇·H₂O
M_r	499.54
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	293
a, b, c (Å)	15.1489 (2), 6.5736 (1), 15.3111 (2)
β (°)	93.557 (1)
V (Å³)	1521.78 (4)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	2.70
Crystal size (mm)	0.19 × 0.18 × 0.16

Data collection
Diffractometer	Bruker APEXII area-detector
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.608, 0.650
No. of measured, independent and observed [I > 2σ(I)] reflections	13176, 3654, 3126
R_int	0.028
(sin θ/λ)_max (Å⁻¹)	0.660

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.024, 0.056, 1.03
No. of reflections	3654
No. of parameters	256
No. of restraints	14
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.57, −0.53

Computer programs: APEX2 (Bruker, 2004), SAINT (Bruker, 2004), SAINT, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), DIAMOND (Brandenburg, 2004), SHELXTL (Bruker, 1997).