The non-centrosymmetric polymorph of (quinolin-8-ol-κ2N,O)(quinolin-8-olato-κ2N,O)silver(I)

Jia, Z.-B.; Zhao, Y.; Wen, Q.-J.; Ma, A.-Q.

doi:10.1107/S160053681300281X

metal-organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 69| Part 3| March 2013| Page m133

doi:10.1107/S160053681300281X

Open

access

The non-centrosymmetric polymorph of (quinolin-8-ol-κ²N,O)(quinolin-8-olato-κ²N,O)silver(I)

Zhen-Bin Jia,^a Yi Zhao,^b Qiu-Jia Wen ^b and Ai-Qing Ma ^a ^*

^aSchool of Pharmacy, Guangdong Medical College, Dongguan 523808, People's Republic of China, and ^bSchool of Clinical Medicine, Guangdong Medical College, Dongguan 523808, People's Republic of China
^*Correspondence e-mail: maq197511@yahoo.com.cn

(Received 8 January 2013; accepted 28 January 2013; online 2 February 2013)

The title compound, [Ag(C₉H₆NO)(C₉H₇NO)], crystallizes as a non-centrosymmetric polymorph. The structure was previously reported by Wu et al. [(2006). Acta Cryst. E62, m281–m282] in the centrosymmetric space group Pbcn. The Ag^I ion displays a distorted tetrahedral coordination geometry defined by two N and two O atoms from a neutral quinolin-8-ol ligand (HQ) and a deprotonated quinolin-8-olate anion (Q⁻). The dihedral angle between the two ligands is 47.0 (1)°. Strong O—H⋯O hydrogen bonds link the molecules into a supramolecular chain along the a-axis direction.

Related literature

For the centrosymmetric polymorph, see: Wu et al. (2006 ).

Experimental

Crystal data

[Ag(C₉H₆NO)(C₉H₇NO)]
M_r = 397.17
Orthorhombic, P 2₁ 2₁ 2₁
a = 7.2320 (3) Å
b = 10.4857 (6) Å
c = 18.9398 (10) Å
V = 1436.25 (13) Å³
Z = 4
Mo Kα radiation
μ = 1.42 mm⁻¹
T = 293 K
0.19 × 0.18 × 0.15 mm

Data collection

Bruker SMART diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2002 ) T_min = 0.884, T_max = 1.000
8103 measured reflections
2554 independent reflections
2305 reflections with I > 2σ(I)
R_int = 0.033

Refinement

R[F² > 2σ(F²)] = 0.027
wR(F²) = 0.057
S = 1.08
2554 reflections
208 parameters
H-atom parameters constrained
Δρ_max = 0.41 e Å⁻³
Δρ_min = −0.34 e Å⁻³
Absolute structure: Flack (1983 ), 1056 Friedel pairs
Flack parameter: −0.02 (3)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2A⋯O1ⁱ	0.82	1.73	2.495 (3)	154
Symmetry code: (i) x-1, y, 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: ORTEP-3 for Windows (Farrugia, 2012 ); software used to prepare material for publication: WinGX (Farrugia, 2012).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S160053681300281X/hg5282sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S160053681300281X/hg5282Isup2.hkl

checkCIF report

Comment top

In the title compound,(I), the Ag ion is four-coordinated by two nitrogen atoms and two oxygen atoms from two 8-hydroxyquinoline ligands, forming a distorted tetrahedral geometry (Fig. 1). The two 8-hydroxyquinoline ligands are different in their mode of the coordination. One is a neutral ligand while the other is deprotonated. The dihedral angle between two 8-hydroxyquinoline mean planes is 47.0 (1)°. A polymorph (II) of the structure has been previously reported by Wu et al. (2006) in the centrosymmetric space group Pbcn with a = 11.434 (2)Å, b = 14.817 (3)Å, c = 8.7828 (18)Å. The Ag-N bondlengths of 2.174 (3), 2.176 (3)Å in (I) are shorter than the value of 2.2377 (19)Å for (II) while the Ag-O bondlengths of 2.596 (2), 2.649 (2)Å are longer than the value of 2.4831 (17)Å found for (II). Inter-molecular O_H···O hydrogen bonding between HQ and Q^- ligands form a supramolecular chain structure (Table 1, Fig. 2). Weak π-π interactions are observed between neighboring aromatic rings [dihedral angle 2.0 (2)°] with the centroid-to-centroid distance of 3.75 (1) Å, which is favorable to increase the stability of the structure (Fig. 3).

Related literature top

For the centrosymmetric polymorph, see: Wu et al. (2006).

Experimental top

A methanol solution (15 ml) of 8-hydroxyquinoline(HQ) (0.075 g,0.5 mmol) was mixed with an aqueous solution (5 ml) of AgNO₃ (0.085 g, 0.5 mmol). Ammonia solution was dropped into the mixture under stirring until it was almost clear. Then it was filtered. Yellow single crystals, suitable for X-ray, were obtained after several days.

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: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: WinGX (Farrugia, 2012).

Figures top

	Fig. 1. The molecular structure of (I).
	Fig. 2. View of the hydrogen-bonding chain of (1). Hydrogen bonds are drawn as dashed lines.
	Fig. 3. View of the packing. H atoms have been omitted for clarity.

(Quinolin-8-ol-κ²N,O)(quinolin-8-olato-κ²N,O)silver(I) top

Crystal data top

[Ag(C₉H₆NO)(C₉H₇NO)]	F(000) = 792
M_r = 397.17	D_x = 1.837 Mg m⁻³
Orthorhombic, P2₁2₁2₁	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 3403 reflections
a = 7.2320 (3) Å	θ = 2.8–29.6°
b = 10.4857 (6) Å	µ = 1.42 mm⁻¹
c = 18.9398 (10) Å	T = 293 K
V = 1436.25 (13) Å³	Block, yellow
Z = 4	0.19 × 0.18 × 0.15 mm

Data collection top

Bruker SMART diffractometer	2554 independent reflections
Radiation source: Enhance (Mo) X-ray Source	2305 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.033
Detector resolution: 10.3592 pixels mm^-1	θ_max = 25.1°, θ_min = 2.9°
ω scans	h = −8→7
Absorption correction: multi-scan (SADABS; Bruker, 2002)	k = −9→12
T_min = 0.884, T_max = 1.000	l = −22→21
8103 measured reflections

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)] = 0.027	H-atom parameters constrained
wR(F²) = 0.057	w = 1/[σ²(F_o²) + (0.022P)² + 0.3181P] where P = (F_o² + 2F_c²)/3
S = 1.08	(Δ/σ)_max = 0.001
2554 reflections	Δρ_max = 0.41 e Å⁻³
208 parameters	Δρ_min = −0.34 e Å⁻³
0 restraints	Absolute structure: Flack (1983), 1056 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.02 (3)

Crystal data top

[Ag(C₉H₆NO)(C₉H₇NO)]	V = 1436.25 (13) Å³
M_r = 397.17	Z = 4
Orthorhombic, P2₁2₁2₁	Mo Kα radiation
a = 7.2320 (3) Å	µ = 1.42 mm⁻¹
b = 10.4857 (6) Å	T = 293 K
c = 18.9398 (10) Å	0.19 × 0.18 × 0.15 mm

Data collection top

Bruker SMART diffractometer	2554 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2002)	2305 reflections with I > 2σ(I)
T_min = 0.884, T_max = 1.000	R_int = 0.033
8103 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.027	H-atom parameters constrained
wR(F²) = 0.057	Δρ_max = 0.41 e Å⁻³
S = 1.08	Δρ_min = −0.34 e Å⁻³
2554 reflections	Absolute structure: Flack (1983), 1056 Friedel pairs
208 parameters	Absolute structure parameter: −0.02 (3)
0 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
C17	0.3321 (5)	0.5388 (4)	0.2207 (2)	0.0428 (11)
H17	0.2247	0.4904	0.2240	0.051*
C18	0.4685 (6)	0.5214 (4)	0.2684 (2)	0.0413 (11)
H18	0.4528	0.4635	0.3051	0.050*
Ag1	0.87935 (4)	0.85088 (3)	0.101833 (16)	0.04331 (11)
C6	1.4013 (5)	1.0168 (4)	−0.0955 (2)	0.0428 (10)
H6	1.5083	1.0187	−0.1227	0.051*
O2	0.5261 (3)	0.7849 (2)	0.10618 (14)	0.0319 (6)
H2A	0.4318	0.7863	0.0821	0.048*
O1	1.2184 (3)	0.8451 (3)	0.05683 (12)	0.0347 (6)
C8	1.2323 (5)	0.9235 (4)	0.00265 (19)	0.0279 (8)
C7	1.3899 (6)	0.9315 (4)	−0.03871 (19)	0.0360 (9)
H7	1.4903	0.8791	−0.0286	0.043*
C9	1.0833 (4)	1.0077 (3)	−0.01372 (18)	0.0264 (8)
C13	0.6343 (5)	0.5908 (3)	0.26259 (18)	0.0300 (8)
C15	0.5067 (5)	0.6993 (3)	0.15794 (19)	0.0268 (8)
N1	0.9246 (4)	1.0033 (3)	0.02576 (16)	0.0309 (8)
N2	0.8161 (4)	0.7483 (3)	0.19863 (16)	0.0280 (7)
C11	0.9365 (5)	0.6477 (5)	0.3027 (2)	0.0406 (10)
H11	1.0325	0.6407	0.3352	0.049*
C16	0.3498 (5)	0.6289 (4)	0.1662 (2)	0.0372 (9)
H16	0.2520	0.6408	0.1350	0.045*
C14	0.6564 (4)	0.6808 (3)	0.20672 (18)	0.0245 (8)
C2	0.7975 (5)	1.1738 (4)	−0.0422 (2)	0.0435 (11)
H2	0.6996	1.2297	−0.0497	0.052*
C4	1.0976 (5)	1.0959 (3)	−0.07134 (19)	0.0325 (9)
C3	0.9487 (6)	1.1781 (4)	−0.0839 (2)	0.0411 (11)
H3	0.9540	1.2359	−0.1211	0.049*
C10	0.9497 (5)	0.7328 (4)	0.2455 (2)	0.0404 (10)
H10	1.0574	0.7804	0.2404	0.048*
C1	0.7905 (5)	1.0843 (4)	0.0121 (2)	0.0414 (11)
H1	0.6851	1.0818	0.0402	0.050*
C12	0.7824 (6)	0.5764 (4)	0.3098 (2)	0.0388 (10)
H12	0.7742	0.5172	0.3462	0.047*
C5	1.2597 (5)	1.0971 (4)	−0.1118 (2)	0.0401 (10)
H5	1.2705	1.1526	−0.1498	0.048*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C17	0.033 (2)	0.037 (3)	0.059 (3)	−0.0098 (19)	0.0030 (19)	0.007 (2)
C18	0.047 (2)	0.035 (3)	0.042 (3)	0.002 (2)	0.010 (2)	0.015 (2)
Ag1	0.04359 (16)	0.04830 (19)	0.03805 (17)	−0.00869 (17)	0.00683 (17)	0.01115 (17)
C6	0.039 (2)	0.054 (3)	0.036 (2)	−0.013 (2)	0.013 (2)	−0.006 (2)
O2	0.0300 (11)	0.0322 (14)	0.0337 (14)	−0.0030 (11)	−0.0046 (13)	0.0085 (14)
O1	0.0289 (12)	0.0401 (16)	0.0350 (14)	0.0029 (14)	−0.0021 (11)	0.0112 (15)
C8	0.0259 (18)	0.031 (2)	0.027 (2)	−0.0041 (18)	−0.0037 (16)	−0.0017 (18)
C7	0.0288 (18)	0.041 (2)	0.038 (2)	0.002 (2)	−0.002 (2)	−0.0019 (18)
C9	0.0271 (19)	0.027 (2)	0.0249 (19)	−0.0052 (17)	−0.0029 (15)	−0.0009 (15)
C13	0.0324 (18)	0.029 (2)	0.028 (2)	0.008 (2)	0.0037 (18)	0.0008 (15)
C15	0.0291 (18)	0.023 (2)	0.028 (2)	0.0052 (16)	0.0018 (16)	0.0009 (17)
N1	0.0246 (16)	0.0364 (19)	0.0318 (18)	−0.0006 (15)	0.0009 (12)	0.0021 (14)
N2	0.0268 (15)	0.0289 (18)	0.0283 (17)	0.0006 (14)	0.0010 (13)	0.0005 (15)
C11	0.037 (2)	0.049 (3)	0.036 (2)	0.005 (2)	−0.0110 (16)	0.006 (2)
C16	0.034 (2)	0.035 (2)	0.043 (2)	−0.004 (2)	−0.0063 (17)	0.0065 (18)
C14	0.0257 (17)	0.022 (2)	0.0257 (18)	0.0052 (16)	0.0037 (14)	−0.0016 (15)
C2	0.041 (2)	0.042 (3)	0.048 (3)	0.014 (2)	−0.009 (2)	0.007 (2)
C4	0.039 (2)	0.029 (2)	0.029 (2)	−0.008 (2)	−0.0038 (17)	0.0036 (15)
C3	0.053 (2)	0.030 (2)	0.040 (3)	−0.0032 (19)	−0.0094 (19)	0.0092 (19)
C10	0.032 (2)	0.050 (3)	0.040 (2)	0.002 (2)	−0.0016 (18)	0.000 (2)
C1	0.031 (2)	0.049 (3)	0.044 (3)	0.008 (2)	0.0000 (19)	−0.003 (2)
C12	0.051 (2)	0.034 (3)	0.030 (2)	0.003 (2)	0.0009 (19)	0.0078 (19)
C5	0.044 (2)	0.041 (3)	0.035 (2)	−0.010 (2)	0.001 (2)	0.011 (2)

Geometric parameters (Å, º) top

C17—C18	1.349 (6)	C13—C14	1.427 (5)
C17—C16	1.406 (5)	C15—C16	1.362 (5)
C17—H17	0.9300	C15—C14	1.436 (5)
C18—C13	1.407 (6)	N1—C1	1.316 (5)
C18—H18	0.9300	N2—C10	1.322 (5)
Ag1—N2	2.174 (3)	N2—C14	1.364 (4)
Ag1—N1	2.176 (3)	C11—C12	1.348 (5)
Ag1—O1	2.596 (2)	C11—C10	1.408 (6)
Ag1—O2	2.649 (2)	C11—H11	0.9300
C6—C5	1.361 (6)	C16—H16	0.9300
C6—C7	1.401 (5)	C2—C3	1.349 (5)
C6—H6	0.9300	C2—C1	1.394 (6)
O2—C15	1.336 (4)	C2—H2	0.9300
O2—H2A	0.8200	C4—C3	1.400 (5)
O1—C8	1.319 (4)	C4—C5	1.400 (6)
C8—C7	1.386 (5)	C3—H3	0.9300
C8—C9	1.427 (5)	C10—H10	0.9300
C7—H7	0.9300	C1—H1	0.9300
C9—N1	1.370 (4)	C12—H12	0.9300
C9—C4	1.434 (5)	C5—H5	0.9300
C13—C12	1.403 (5)

C18—C17—C16	121.1 (4)	C9—N1—Ag1	120.8 (2)
C18—C17—H17	119.5	C10—N2—C14	118.7 (3)
C16—C17—H17	119.5	C10—N2—Ag1	118.3 (2)
C17—C18—C13	120.1 (4)	C14—N2—Ag1	122.0 (2)
C17—C18—H18	120.0	C12—C11—C10	118.9 (3)
C13—C18—H18	120.0	C12—C11—H11	120.5
N2—Ag1—N1	162.38 (12)	C10—C11—H11	120.5
N2—Ag1—O1	117.62 (9)	C15—C16—C17	121.6 (3)
N1—Ag1—O1	70.00 (10)	C15—C16—H16	119.2
N2—Ag1—O2	69.00 (9)	C17—C16—H16	119.2
N1—Ag1—O2	110.96 (9)	N2—C14—C13	121.4 (3)
O1—Ag1—O2	156.21 (9)	N2—C14—C15	119.7 (3)
C5—C6—C7	121.7 (4)	C13—C14—C15	118.8 (3)
C5—C6—H6	119.2	C3—C2—C1	118.9 (4)
C7—C6—H6	119.2	C3—C2—H2	120.5
C15—O2—H2A	109.5	C1—C2—H2	120.5
C8—O1—Ag1	108.2 (2)	C3—C4—C5	123.0 (4)
O1—C8—C7	122.7 (3)	C3—C4—C9	118.1 (4)
O1—C8—C9	119.8 (3)	C5—C4—C9	118.8 (3)
C7—C8—C9	117.4 (3)	C2—C3—C4	120.2 (4)
C8—C7—C6	121.4 (4)	C2—C3—H3	119.9
C8—C7—H7	119.3	C4—C3—H3	119.9
C6—C7—H7	119.3	N2—C10—C11	123.1 (4)
N1—C9—C8	119.5 (3)	N2—C10—H10	118.5
N1—C9—C4	119.8 (3)	C11—C10—H10	118.5
C8—C9—C4	120.6 (3)	N1—C1—C2	123.6 (4)
C12—C13—C18	123.1 (3)	N1—C1—H1	118.2
C12—C13—C14	117.3 (4)	C2—C1—H1	118.2
C18—C13—C14	119.7 (3)	C11—C12—C13	120.5 (4)
O2—C15—C16	122.3 (3)	C11—C12—H12	119.7
O2—C15—C14	118.9 (3)	C13—C12—H12	119.7
C16—C15—C14	118.8 (3)	C6—C5—C4	120.0 (4)
C1—N1—C9	119.2 (3)	C6—C5—H5	120.0
C1—N1—Ag1	119.6 (3)	C4—C5—H5	120.0

C16—C17—C18—C13	−2.2 (7)	Ag1—N2—C14—C13	165.2 (2)
N2—Ag1—O1—C8	−173.2 (2)	C10—N2—C14—C15	177.8 (3)
N1—Ag1—O1—C8	−10.6 (2)	Ag1—N2—C14—C15	−14.3 (4)
Ag1—O1—C8—C7	−172.3 (3)	C12—C13—C14—N2	1.3 (5)
Ag1—O1—C8—C9	9.9 (4)	C18—C13—C14—N2	−178.9 (3)
O1—C8—C7—C6	−179.3 (4)	C12—C13—C14—C15	−179.2 (3)
C9—C8—C7—C6	−1.4 (5)	C18—C13—C14—C15	0.6 (5)
C5—C6—C7—C8	1.1 (6)	O2—C15—C14—N2	−1.4 (5)
O1—C8—C9—N1	−2.1 (5)	C16—C15—C14—N2	178.7 (3)
C7—C8—C9—N1	−180.0 (3)	O2—C15—C14—C13	179.1 (3)
O1—C8—C9—C4	178.4 (3)	C16—C15—C14—C13	−0.9 (5)
C7—C8—C9—C4	0.5 (5)	N1—C9—C4—C3	1.9 (5)
C17—C18—C13—C12	−179.3 (4)	C8—C9—C4—C3	−178.6 (3)
C17—C18—C13—C14	0.9 (6)	N1—C9—C4—C5	−178.8 (3)
C8—C9—N1—C1	177.5 (3)	C8—C9—C4—C5	0.7 (5)
C4—C9—N1—C1	−3.0 (5)	C1—C2—C3—C4	−1.6 (6)
C8—C9—N1—Ag1	−9.7 (4)	C5—C4—C3—C2	−178.9 (4)
C4—C9—N1—Ag1	169.8 (2)	C9—C4—C3—C2	0.4 (6)
N2—Ag1—N1—C1	−57.9 (5)	C14—N2—C10—C11	1.4 (6)
O1—Ag1—N1—C1	−176.8 (3)	Ag1—N2—C10—C11	−167.0 (3)
N2—Ag1—N1—C9	129.4 (4)	C12—C11—C10—N2	1.3 (6)
O1—Ag1—N1—C9	10.4 (2)	C9—N1—C1—C2	1.8 (6)
N1—Ag1—N2—C10	−84.3 (4)	Ag1—N1—C1—C2	−171.1 (3)
O1—Ag1—N2—C10	27.5 (3)	C3—C2—C1—N1	0.5 (7)
N1—Ag1—N2—C14	107.7 (4)	C10—C11—C12—C13	−2.7 (6)
O1—Ag1—N2—C14	−140.4 (2)	C18—C13—C12—C11	−178.3 (4)
O2—C15—C16—C17	179.7 (4)	C14—C13—C12—C11	1.5 (6)
C14—C15—C16—C17	−0.4 (6)	C7—C6—C5—C4	0.2 (6)
C18—C17—C16—C15	2.0 (7)	C3—C4—C5—C6	178.2 (4)
C10—N2—C14—C13	−2.7 (5)	C9—C4—C5—C6	−1.1 (6)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2A···O1ⁱ	0.82	1.73	2.495 (3)	154

Symmetry code: (i) x−1, y, z.

Experimental details

Crystal data
Chemical formula	[Ag(C₉H₆NO)(C₉H₇NO)]
M_r	397.17
Crystal system, space group	Orthorhombic, P2₁2₁2₁
Temperature (K)	293
a, b, c (Å)	7.2320 (3), 10.4857 (6), 18.9398 (10)
V (Å³)	1436.25 (13)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	1.42
Crystal size (mm)	0.19 × 0.18 × 0.15

Data collection
Diffractometer	Bruker SMART diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2002)
T_min, T_max	0.884, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	8103, 2554, 2305
R_int	0.033
(sin θ/λ)_max (Å⁻¹)	0.597

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.027, 0.057, 1.08
No. of reflections	2554
No. of parameters	208
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.41, −0.34
Absolute structure	Flack (1983), 1056 Friedel pairs
Absolute structure parameter	−0.02 (3)

Computer programs: SMART (Bruker, 2002), SAINT (Bruker, 2002), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 2012), WinGX (Farrugia, 2012).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2A···O1ⁱ	0.82	1.73	2.495 (3)	154.4

Symmetry code: (i) x−1, y, z.

Acknowledgements

The authors acknowledge the Guangdong Medical College for financial support (Q2009028, 2010 C3102003, 200910815266) and thank H. P. Xiao for the data collection.

References

Bruker (2002). SADABS, SAINT and SMART. 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
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
Wu, H., Dong, X.-W., Liu, H.-Y. & Ma, J.-F. (2006). Acta Cryst. E62, m281–m282. Web of Science CSD CrossRef IUCr Journals 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.