Bis(2,2′-bipyridine-κ2N,N′)(croconato-κ2O,O′)nickel(II)

Chen, H.-F.; Fang, Q.; Yu, W.-T.

doi:10.1107/S1600536808033771

metal-organic compounds

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ISSN: 2056-9890

Volume 64| Part 11| November 2008| Page m1459

doi:10.1107/S1600536808033771

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Bis(2,2′-bipyridine-κ²N,N′)(croconato-κ²O,O′)nickel(II)

Hong-Feng Chen,^a Qi Fang ^a ^* and Wen-Tao Yu ^a

^aState Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, Shandong Province, People's Republic of China
^*Correspondence e-mail: fangqi@sdu.edu.cn

(Received 17 September 2008; accepted 16 October 2008; online 25 October 2008)

The title compound, [Ni(C₅O₅)(C₁₀H₈N₂)₂], lies across a crystallographic twofold axis, around which two 2,2′-bipyridine (2,2′-bipy) ligands are arranged in a propeller manner. The local geometry of the NiN₄O₂ coordination core basically adopts an octahedral geometry. The molecular twofold axis is along the direction of the molecular dipole moment, and the complex is packed with its dipole moment alternately along the +b and −b directions. The crystal structure is stabilized by intermolecular C—H⋯O hydrogen bonds.

Related literature

For the synthesis, see: Chen et al. (2008 ). For related structures, see: Chen et al. (2005 , 2007 ). For other related literature, see: Coronado et al. (2007 ); Wang et al. (2002 ).

Experimental

Crystal data

[Ni(C₅O₅)(C₁₀H₈N₂)₂]
M_r = 511.13
Orthorhombic, P b c n
a = 12.725 (5) Å
b = 10.752 (5) Å
c = 15.733 (5) Å
V = 2152.6 (15) Å³
Z = 4
Mo Kα radiation
μ = 0.95 mm⁻¹
T = 293 (2) K
0.20 × 0.19 × 0.10 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (APEX2; Bruker, 2005 ) T_min = 0.821, T_max = 0.902
10055 measured reflections
2466 independent reflections
1536 reflections with I > 2σ(I)
R_int = 0.089

Refinement

R[F² > 2σ(F²)] = 0.044
wR(F²) = 0.102
S = 1.02
2466 reflections
160 parameters
H-atom parameters constrained
Δρ_max = 0.26 e Å⁻³
Δρ_min = −0.38 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C4—H4⋯O1ⁱ	0.93	2.57	3.340 (4)	141
C8—H8⋯O2ⁱⁱ	0.93	2.24	3.114 (4)	156
C9—H9⋯O3ⁱⁱⁱ	0.93	2.57	3.222 (4)	127
Symmetry codes: (i) $[x, -y+1, z+{\script{1\over 2}}]$ ; (ii) $[-x+{\script{3\over 2}}, -y+{\script{1\over 2}}, z+{\script{1\over 2}}]$ ; (iii) $[x+{\script{1\over 2}}, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ .

Data collection: APEX2 (Bruker, 2005); cell refinement: APEX2; data reduction: APEX2; 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: WinGX (Farrugia, 1999 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808033771/lx2071sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808033771/lx2071Isup2.hkl

checkCIF report

Comment top

The croconate C₅O₅^2- anion has attracted increasing attention in recent years because this polydentate ligand gave rise to a variety of interesting complexes (Chen et al., 2008; Coronado et al., 2007; Chen et al., 2005; Wang et al., 2002;). Typically, the C₅O₅^2- anion serves as a terminal bidentate chelate ligand or a bridging ligand utilizing more than two O atoms for coordination. We previously reported a mixing-coordinated complex [Ni(C₅O₅)(phen)₂] with 1,10-phenanthroline (phen) as the first ligand and the C₅O₅^2- anion as the second ligand (Chen et al., 2007). The similar chelating behavior of 2,2'-bipy and 1,10-phen prompted us to replace phen ligand by 2,2'-bipy. In this report, the structure of this mixing-coordinated complex is reported.

The title compound crystalizes to the same space group as [Ni(C₅O₅)(phen)₂]. Both crystals have very similar cell parameters and show many common features. The chiral molecule lies across twofold axis which is along the direction of the molecular dipole moment. Around the molecular axis, two 2,2'-bipy ligands are arranged in a propeller manner. The Ni²⁺ is coordinated by four N atoms of the two 2,2'-bipy ligands and two O atoms of a croconate ligand to furnish a slightly distored octahedral NiN₄O₂ coordination core. The dihedral angle between the croconate plane and a 2,2'-bipy plane is 88.7 (1)°, and that between the two 2,2'-bipy planes is 81.9 (1)° in [Ni(C₅O₅) (2,2'-bipy)₂]. These are close to the corresponding dihedral angles (86.9 (1)° and 86.6 (1)°) in [Ni(C₅O₅)(phen)₂]. The C—O bond lengths involving coordinated O atoms are longer than those of other C—O bonds. In both crystals, molecules packed alternately along +b and-b directions.

However, we can not fail to notice some differences between the two crystals. The Ni—O band length of [Ni(C₅O₅)(2,2'-bipy)₂] {2.102 (2) Å} is longer than that {2.098 (3) Å} of [Ni(C₅O₅)(phen)₂]. Meanwhile, the Ni—N band lengths of [Ni(C₅O₅)(2,2'-bipy)₂] {2.059 (2), 2.066 (2) Å} is considerably shorter than those {2.071 (3), 2.088 (3) Å} of [Ni(C₅O₅)(phen)₂]. It seems that 2,2'-bipyridine is a stronger ligand to Ni²⁺ in comparison with 1,10-phenanthroline. The crystal structure is stabilized by intermolecular C—H···O hydrogen bonds (Table 1).

Related literature top

For the synthesis, see: Chen et al. (2008). For related structures, see: Chen et al. (2005, 2007). For other related literature, see: Coronado et al. (2007); Wang et al. (2002).

Experimental top

[K₂(C₅O₅)] (0.050 g, 0.23 mmol) and NiCl₂.6H₂O (0.060 g, 0.25 mmol) were dissolved in mixed solvent of water (15 ml) and dimethylformamide (10 ml). Then 2,2'-bipy (0.080 g, 0.51 mmol) was added. The mixture was heated to 340–350 K under continuous stirring for 20 min and then filtered. The green-yellow prisms crystals were obtained by slow evaporation at 313 K.

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: APEX2 (Bruker, 2005); data reduction: APEX2 (Bruker, 2005); 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: WinGX (Farrugia, 1999).

Figures top

Fig. 1. The molecular structure of [Ni(C₅O₅) (2,2'-bipy)₂]. Displacement ellipsoids are drawn at the 30% probability level and H atoms have been omitted. [symmetry code: (i) -x + 1, y, -z + 3/2.]

Bis(2,2'-bipyridine-κ²N,N')(croconato-κ²O,O')nickel(II) top

Crystal data top

[Ni(C₅O₅)(C₁₀H₈N₂)₂]	F(000) = 1048
M_r = 511.13	D_x = 1.577 Mg m⁻³
Orthorhombic, Pbcn	Mo Kα radiation, λ = 0.71069 Å
Hall symbol: -P_2n 2ab	Cell parameters from 2518 reflections
a = 12.725 (5) Å	θ = 2.5–23.4°
b = 10.752 (5) Å	µ = 0.95 mm⁻¹
c = 15.733 (5) Å	T = 293 K
V = 2152.6 (15) Å³	Prism, green-yellow
Z = 4	0.20 × 0.19 × 0.10 mm

Data collection top

Bruker APEXII CCD diffractometer	2466 independent reflections
Radiation source: fine-focus sealed tube	1536 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.089
Detector resolution: 10.0 pixels mm^-1	θ_max = 27.5°, θ_min = 2.5°
ϕ and ω scans	h = −15→16
Absorption correction: multi-scan (APEX2; Bruker, 2005)	k = −13→10
T_min = 0.821, T_max = 0.902	l = −20→19
10055 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)] = 0.044	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.102	H-atom parameters constrained
S = 1.02	w = 1/[σ²(F_o²) + (0.0372P)² + 0.0108P] where P = (F_o² + 2F_c²)/3
2466 reflections	(Δ/σ)_max < 0.001
160 parameters	Δρ_max = 0.26 e Å⁻³
0 restraints	Δρ_min = −0.38 e Å⁻³

Crystal data top

[Ni(C₅O₅)(C₁₀H₈N₂)₂]	V = 2152.6 (15) Å³
M_r = 511.13	Z = 4
Orthorhombic, Pbcn	Mo Kα radiation
a = 12.725 (5) Å	µ = 0.95 mm⁻¹
b = 10.752 (5) Å	T = 293 K
c = 15.733 (5) Å	0.20 × 0.19 × 0.10 mm

Data collection top

Bruker APEXII CCD diffractometer	2466 independent reflections
Absorption correction: multi-scan (APEX2; Bruker, 2005)	1536 reflections with I > 2σ(I)
T_min = 0.821, T_max = 0.902	R_int = 0.089
10055 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.044	0 restraints
wR(F²) = 0.102	H-atom parameters constrained
S = 1.02	Δρ_max = 0.26 e Å⁻³
2466 reflections	Δρ_min = −0.38 e Å⁻³
160 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 > 2sigma(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
Ni1	0.5000	0.46011 (4)	0.2500	0.03546 (17)
O1	0.56048 (15)	0.31353 (15)	0.17633 (10)	0.0439 (5)
O2	0.6016 (2)	0.0512 (2)	0.12408 (16)	0.1053 (10)
O3	0.5000	−0.1097 (3)	0.2500	0.0700 (9)
N1	0.45364 (18)	0.58822 (19)	0.34037 (12)	0.0397 (5)
N2	0.63184 (17)	0.46676 (19)	0.32573 (12)	0.0419 (6)
C1	0.3650 (3)	0.6535 (3)	0.34092 (17)	0.0531 (8)
H1	0.3173	0.6410	0.2970	0.064*
C2	0.3402 (3)	0.7384 (3)	0.4029 (2)	0.0717 (10)
H2	0.2774	0.7824	0.4013	0.086*
C3	0.4114 (4)	0.7561 (3)	0.4673 (2)	0.0742 (11)
H3	0.3977	0.8142	0.5097	0.089*
C4	0.5025 (3)	0.6888 (3)	0.46926 (18)	0.0570 (9)
H4	0.5502	0.6989	0.5135	0.068*
C5	0.5226 (2)	0.6052 (2)	0.40425 (15)	0.0406 (7)
C6	0.6200 (2)	0.5320 (2)	0.39824 (16)	0.0431 (7)
C7	0.6964 (3)	0.5264 (3)	0.4613 (2)	0.0638 (9)
H7	0.6872	0.5696	0.5119	0.077*
C8	0.7854 (3)	0.4569 (4)	0.4486 (2)	0.0770 (12)
H8	0.8367	0.4526	0.4906	0.092*
C9	0.7982 (2)	0.3940 (3)	0.3737 (2)	0.0679 (10)
H9	0.8587	0.3479	0.3633	0.081*
C10	0.7195 (2)	0.4008 (3)	0.31437 (19)	0.0575 (8)
H10	0.7276	0.3572	0.2637	0.069*
C11	0.5300 (2)	0.2129 (3)	0.21214 (15)	0.0393 (6)
C12	0.5511 (3)	0.0864 (3)	0.18605 (18)	0.0530 (8)
C13	0.5000	0.0035 (4)	0.2500	0.0487 (10)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Ni1	0.0404 (3)	0.0388 (3)	0.0271 (2)	0.000	−0.0053 (2)	0.000
O1	0.0587 (13)	0.0418 (11)	0.0310 (9)	−0.0040 (10)	0.0083 (9)	0.0013 (8)
O2	0.167 (3)	0.0586 (15)	0.0903 (17)	−0.0026 (15)	0.0769 (19)	−0.0177 (13)
O3	0.086 (2)	0.0405 (17)	0.084 (2)	0.000	0.0118 (18)	0.000
N1	0.0510 (14)	0.0360 (12)	0.0322 (11)	−0.0008 (12)	−0.0020 (11)	0.0015 (10)
N2	0.0437 (14)	0.0480 (14)	0.0340 (12)	0.0003 (12)	−0.0082 (10)	0.0017 (10)
C1	0.064 (2)	0.0507 (18)	0.0443 (16)	0.0138 (17)	0.0003 (16)	0.0011 (14)
C2	0.098 (3)	0.057 (2)	0.060 (2)	0.024 (2)	0.022 (2)	−0.0018 (17)
C3	0.119 (3)	0.048 (2)	0.056 (2)	−0.002 (2)	0.028 (2)	−0.0121 (16)
C4	0.084 (2)	0.0514 (17)	0.0359 (15)	−0.022 (2)	0.0095 (16)	−0.0076 (13)
C5	0.0582 (19)	0.0341 (14)	0.0295 (13)	−0.0130 (14)	0.0012 (12)	0.0026 (11)
C6	0.0535 (18)	0.0442 (16)	0.0317 (14)	−0.0198 (15)	−0.0080 (13)	0.0070 (13)
C7	0.076 (2)	0.068 (2)	0.0482 (18)	−0.023 (2)	−0.0272 (17)	0.0038 (15)
C8	0.065 (2)	0.090 (3)	0.076 (3)	−0.023 (2)	−0.041 (2)	0.033 (2)
C9	0.0442 (18)	0.080 (3)	0.079 (2)	0.0036 (19)	−0.0144 (18)	0.026 (2)
C10	0.0494 (19)	0.067 (2)	0.0555 (19)	0.0078 (18)	−0.0081 (15)	0.0055 (16)
C11	0.0431 (17)	0.0439 (16)	0.0309 (13)	−0.0025 (14)	−0.0005 (11)	−0.0019 (12)
C12	0.066 (2)	0.0462 (17)	0.0463 (17)	−0.0038 (17)	0.0129 (16)	−0.0085 (14)
C13	0.052 (2)	0.042 (2)	0.052 (2)	0.000	0.000 (2)	0.000

Geometric parameters (Å, º) top

Ni1—N2	2.059 (2)	C3—C4	1.367 (4)
Ni1—N2ⁱ	2.059 (2)	C3—H3	0.9300
Ni1—N1	2.066 (2)	C4—C5	1.385 (4)
Ni1—N1ⁱ	2.066 (2)	C4—H4	0.9300
Ni1—O1ⁱ	2.1022 (18)	C5—C6	1.472 (4)
Ni1—O1	2.1022 (18)	C6—C7	1.389 (4)
O1—C11	1.280 (3)	C7—C8	1.371 (5)
O2—C12	1.227 (3)	C7—H7	0.9300
O3—C13	1.217 (5)	C8—C9	1.369 (5)
N1—C1	1.328 (3)	C8—H8	0.9300
N1—C5	1.347 (3)	C9—C10	1.370 (4)
N2—C10	1.334 (3)	C9—H9	0.9300
N2—C6	1.347 (3)	C10—H10	0.9300
C1—C2	1.372 (4)	C11—C11ⁱ	1.415 (5)
C1—H1	0.9300	C11—C12	1.446 (4)
C2—C3	1.373 (5)	C12—C13	1.493 (4)
C2—H2	0.9300	C13—C12ⁱ	1.493 (4)

N2—Ni1—N2ⁱ	176.02 (12)	C3—C4—C5	118.9 (3)
N2—Ni1—N1	79.12 (9)	C3—C4—H4	120.6
N2ⁱ—Ni1—N1	98.19 (8)	C5—C4—H4	120.6
N2—Ni1—N1ⁱ	98.19 (8)	N1—C5—C4	121.3 (3)
N2ⁱ—Ni1—N1ⁱ	79.12 (9)	N1—C5—C6	115.4 (2)
N1—Ni1—N1ⁱ	96.35 (11)	C4—C5—C6	123.3 (3)
N2—Ni1—O1ⁱ	90.30 (8)	N2—C6—C7	120.2 (3)
N2ⁱ—Ni1—O1ⁱ	92.68 (8)	N2—C6—C5	115.3 (2)
N1—Ni1—O1ⁱ	90.91 (8)	C7—C6—C5	124.5 (3)
N1ⁱ—Ni1—O1ⁱ	169.72 (7)	C8—C7—C6	119.8 (3)
N2—Ni1—O1	92.68 (8)	C8—C7—H7	120.1
N2ⁱ—Ni1—O1	90.30 (8)	C6—C7—H7	120.1
N1—Ni1—O1	169.72 (7)	C9—C8—C7	119.5 (3)
N1ⁱ—Ni1—O1	90.91 (8)	C9—C8—H8	120.2
O1ⁱ—Ni1—O1	82.88 (10)	C7—C8—H8	120.2
C11—O1—Ni1	106.29 (15)	C8—C9—C10	118.2 (3)
C1—N1—C5	118.5 (2)	C8—C9—H9	120.9
C1—N1—Ni1	126.82 (19)	C10—C9—H9	120.9
C5—N1—Ni1	114.72 (18)	N2—C10—C9	123.2 (3)
C10—N2—C6	118.9 (2)	N2—C10—H10	118.4
C10—N2—Ni1	125.83 (19)	C9—C10—H10	118.4
C6—N2—Ni1	114.66 (19)	O1—C11—C11ⁱ	122.26 (14)
N1—C1—C2	123.5 (3)	O1—C11—C12	127.9 (2)
N1—C1—H1	118.3	C11ⁱ—C11—C12	109.83 (15)
C2—C1—H1	118.3	O2—C12—C11	127.8 (3)
C1—C2—C3	117.7 (3)	O2—C12—C13	125.4 (3)
C1—C2—H2	121.1	C11—C12—C13	106.8 (2)
C3—C2—H2	121.1	O3—C13—C12ⁱ	126.64 (17)
C4—C3—C2	120.2 (3)	O3—C13—C12	126.64 (17)
C4—C3—H3	119.9	C12ⁱ—C13—C12	106.7 (3)
C2—C3—H3	119.9

N2—Ni1—O1—C11	90.49 (17)	C1—N1—C5—C6	−178.6 (2)
N2ⁱ—Ni1—O1—C11	−92.14 (18)	Ni1—N1—C5—C6	1.2 (3)
N1—Ni1—O1—C11	53.7 (5)	C3—C4—C5—N1	−1.0 (4)
N1ⁱ—Ni1—O1—C11	−171.27 (17)	C3—C4—C5—C6	177.3 (3)
O1ⁱ—Ni1—O1—C11	0.52 (13)	C10—N2—C6—C7	−2.5 (4)
N2—Ni1—N1—C1	174.7 (2)	Ni1—N2—C6—C7	169.1 (2)
N2ⁱ—Ni1—N1—C1	−2.3 (2)	C10—N2—C6—C5	178.1 (2)
N1ⁱ—Ni1—N1—C1	77.5 (2)	Ni1—N2—C6—C5	−10.3 (3)
O1ⁱ—Ni1—N1—C1	−95.2 (2)	N1—C5—C6—N2	6.1 (3)
O1—Ni1—N1—C1	−147.8 (4)	C4—C5—C6—N2	−172.3 (2)
N2—Ni1—N1—C5	−5.04 (17)	N1—C5—C6—C7	−173.3 (2)
N2ⁱ—Ni1—N1—C5	177.93 (18)	C4—C5—C6—C7	8.3 (4)
N1ⁱ—Ni1—N1—C5	−102.20 (19)	N2—C6—C7—C8	1.8 (4)
O1ⁱ—Ni1—N1—C5	85.09 (18)	C5—C6—C7—C8	−178.8 (3)
O1—Ni1—N1—C5	32.5 (5)	C6—C7—C8—C9	0.2 (5)
N1—Ni1—N2—C10	179.3 (2)	C7—C8—C9—C10	−1.5 (5)
N1ⁱ—Ni1—N2—C10	−85.7 (2)	C6—N2—C10—C9	1.2 (4)
O1ⁱ—Ni1—N2—C10	88.5 (2)	Ni1—N2—C10—C9	−169.4 (2)
O1—Ni1—N2—C10	5.6 (2)	C8—C9—C10—N2	0.8 (5)
N1—Ni1—N2—C6	8.43 (17)	Ni1—O1—C11—C11ⁱ	−1.5 (4)
N1ⁱ—Ni1—N2—C6	103.37 (17)	Ni1—O1—C11—C12	−179.9 (2)
O1ⁱ—Ni1—N2—C6	−82.44 (17)	O1—C11—C12—O2	−0.7 (5)
O1—Ni1—N2—C6	−165.32 (17)	C11ⁱ—C11—C12—O2	−179.3 (3)
C5—N1—C1—C2	0.6 (4)	O1—C11—C12—C13	178.9 (2)
Ni1—N1—C1—C2	−179.1 (2)	C11ⁱ—C11—C12—C13	0.3 (4)
N1—C1—C2—C3	0.1 (5)	O2—C12—C13—O3	−0.6 (4)
C1—C2—C3—C4	−1.2 (5)	C11—C12—C13—O3	179.89 (13)
C2—C3—C4—C5	1.7 (5)	O2—C12—C13—C12ⁱ	179.4 (4)
C1—N1—C5—C4	−0.1 (4)	C11—C12—C13—C12ⁱ	−0.11 (13)
Ni1—N1—C5—C4	179.63 (19)

Symmetry code: (i) −x+1, y, −z+1/2.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C4—H4···O1ⁱⁱ	0.93	2.57	3.340 (4)	141
C8—H8···O2ⁱⁱⁱ	0.93	2.24	3.114 (4)	156
C9—H9···O3^iv	0.93	2.57	3.222 (4)	127

Symmetry codes: (ii) x, −y+1, z+1/2; (iii) −x+3/2, −y+1/2, z+1/2; (iv) x+1/2, y+1/2, −z+1/2.

Experimental details

Crystal data
Chemical formula	[Ni(C₅O₅)(C₁₀H₈N₂)₂]
M_r	511.13
Crystal system, space group	Orthorhombic, Pbcn
Temperature (K)	293
a, b, c (Å)	12.725 (5), 10.752 (5), 15.733 (5)
V (Å³)	2152.6 (15)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.95
Crystal size (mm)	0.20 × 0.19 × 0.10

Data collection
Diffractometer	Bruker APEXII CCD diffractometer
Absorption correction	Multi-scan (APEX2; Bruker, 2005)
T_min, T_max	0.821, 0.902
No. of measured, independent and observed [I > 2σ(I)] reflections	10055, 2466, 1536
R_int	0.089
(sin θ/λ)_max (Å⁻¹)	0.649

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.044, 0.102, 1.02
No. of reflections	2466
No. of parameters	160
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.26, −0.38

Computer programs: APEX2 (Bruker, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008), WinGX (Farrugia, 1999).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C4—H4···O1ⁱ	0.93	2.57	3.340 (4)	140.7
C8—H8···O2ⁱⁱ	0.93	2.24	3.114 (4)	155.8
C9—H9···O3ⁱⁱⁱ	0.93	2.57	3.222 (4)	127.3

Symmetry codes: (i) x, −y+1, z+1/2; (ii) −x+3/2, −y+1/2, z+1/2; (iii) x+1/2, y+1/2, −z+1/2.

Acknowledgements

This work was supported by the PhD Foundation of the Ministry of Education of China and by the National Natural Science Foundation of China (grant No. 50673054).

References

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