5-(2,5-Dioxooxolan-3-yl)-8-methyl-3,3a,4,5-tetra­hydro-1H-naphtho­[1,2-c]furan-1,3-dione

Guo, Y.Z.; Liu, J.G.; Yang, S.Y.

doi:10.1107/S1600536813000482

organic compounds

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ISSN: 2056-9890

Volume 69| Part 2| February 2013| Page o226

doi:10.1107/S1600536813000482

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5-(2,5-Dioxooxolan-3-yl)-8-methyl-3,3a,4,5-tetrahydro-1H-naphtho[1,2-c]furan-1,3-dione

Y. Z. Guo,^a J. G. Liu ^a ^* and S. Y. Yang ^a ^*

^aLaboratory of Advanced Polymer Materials, Institute of Chemistry, Chinese Academy of Sciences (ICCAS), Beijing 100190, People's Republic of China
^*Correspondence e-mail: liujg@iccas.ac.cn, shiyang@iccas.ac.cn

(Received 27 December 2012; accepted 6 January 2013; online 12 January 2013)

In the title compound, C₁₇H₁₄O₆, the dihedral angle between the two anhydride rings is 76.01 (8)°while the dihedral angles between the benzene and anhydride rings are 42.60 (7) and 68.94 (7)°. The cyclohexene ring of the tetrahydronaphthalene unit exhibits an envelope conformation.

Related literature

For applications of tetralin-containing dianhydrides, see: Liaw et al. (2012 ); Matsumoto et al. (2009 ); Hasegawa & Horie (2001 ). For puckering parameters, see: Cremer & Pople (1975 ).

Experimental

Crystal data

C₁₇H₁₄O₆
M_r = 314.28
Triclinic, $[P \overline 1]$
a = 6.6907 (13) Å
b = 9.166 (2) Å
c = 11.839 (2) Å
α = 78.628 (8)°
β = 78.352 (9)°
γ = 79.054 (9)°
V = 688.5 (2) Å³
Z = 2
Mo Kα radiation
μ = 0.12 mm⁻¹
T = 173 K
0.28 × 0.22 × 0.12 mm

Data collection

Rigaku Saturn724+ CCD diffractometer
Absorption correction: multi-scan (CrystalClear; Rigaku, 2008 ) T_min = 0.680, T_max = 1.000
8959 measured reflections
3137 independent reflections
2864 reflections with I > 2σ(I)
R_int = 0.042

Refinement

R[F² > 2σ(F²)] = 0.046
wR(F²) = 0.113
S = 1.07
3137 reflections
209 parameters
H-atom parameters constrained
Δρ_max = 0.32 e Å⁻³
Δρ_min = −0.22 e Å⁻³

Data collection: CrystalClear (Rigaku, 2008); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: OLEX2 (Dolomanov et al., 2009 ); molecular graphics: OLEX2; software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536813000482/vm2186sup1.cif

Supporting information file. DOI: 10.1107/S1600536813000482/vm2186Isup2.cdx

Structure factors: contains datablock I. DOI: 10.1107/S1600536813000482/vm2186Isup3.hkl

Supporting information file. DOI: 10.1107/S1600536813000482/vm2186Isup4.cml

checkCIF report

Comment top

The title compound 3,4-dicarboxy-1,2,3,4-tetrahydro-6-methyl-1-naphthalene succinic dianhydride (MTDA) can be used as monomer for alicyclic polyimide (PI) synthesis (Liaw et al., 2012). Especially, this dianhydride compound is a very promising monomer for developments of organo-soluble and highly-transparent or colorless PI films. Colorless polyimide films have recently attracted much attention in optoelectronic fabrications, such as plastic substrate for flexible display, waveguides for optical interconnection and so on, due to their excellent combined properties, including high thermal stability, high optical transparency, and low dielectric constant (Matsumoto et al., 2009). The asymmetrical alicyclic tetralin moiety in MTDA effectively reduces the inter- or intramolecular interactions and prohibits the formation of charge transfer complex (Hasegawa et al., 2001); thus improving the optical transparency and solubility of the derived PIs.

The title compound has an asymmetrical structure (Fig. 1). The dihedral angle between the best planes through the two anhydride rings is 76.01 (8)°. The dihedral angles between the benzene ring and the anhydride ring 1 (C1-C4/O1) and anhydride ring 2 (C9-C12/O4) is 42.60 (7)° and 68.94 (7)°, respectively. The six-membered cyclohexene ring in the tetrahydronaphthalene residue exhibits an envelope conformation with puckering parameters of Q=0.489 (15) Å, θ=122.8 (2)° and ϕ=300.7 (2)° (Cremer et al., 1975).

Related literature top

For applications of tetralin-containing dianhydrides, see: Liaw et al. (2012); Matsumoto et al. (2009); Hasegawa et al. (2001). For puckering parameters, see: Cremer & Pople (1975).

Experimental top

Maleic anhydride (43.75 g, 0.446 mol), 4-methylstyrene (80.60 g, 0.682 mol), and 2,5-di-tert-butyl hydroquinone (0.1138 g, 0.5 mmol) were put into a 500-ml three-necked flask equipped with a mechanical stirrer, gas inlet, and condenser. Nitrogen was first introduced to remove the air in the system. Then, nitric oxide (NO) was introduced from a gas inlet under the surface of the reaction solution. The reaction mixture were heated to 120°C and maintained for 5 h under an atmosphere of nitric oxide. The produced red-brown nitrogen oxide gas was trapped by passing through an aqueous solution of 20 wt% sodium hydroxide. An orange precipitate formed during the reaction. After the reaction, the mixture was cooled to room temperature and 60 ml of acetonitrile was then added. The reaction mixture was heated to reflux for another 0.5 h. Then, 60 ml of toluene was added and the reaction mixture was cooled to room temperature. The produced white needlelike crystals were collected by filtration and the solid was washed in succesion with toluene and petroleum ether. The obtained white solids were dried in vacuum at 80°C for 24 h. Yield: 51.44 g (73.4%). Elemental analysis: calculated for C₁₇H₁₄O₆: C 64.97, H 4.49%. Found: C 64.32, H 4.44%. EI—MS, m/z: 142 (M⁺-172, 100%). Colorless single crystals were grown by slow evaporation of an acetonitrile solution over a period of several days.

Computing details top

Data collection: CrystalClear (Rigaku, 2008); cell refinement: CrystalClear (Rigaku, 2008); data reduction: CrystalClear (Rigaku, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: OLEX2 (Dolomanov et al., 2009); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

Fig. 1. The molecular structure of the title compound showing displacement ellipsoids at the 30% probability level.

5-(2,5-Dioxooxolan-3-yl)-8-methyl-3,3a,4,5-tetrahydro-1H- naphtho[1,2-c]furan-1,3-dione top

Crystal data top

C₁₇H₁₄O₆	Z = 2
M_r = 314.28	F(000) = 328
Triclinic, P1	D_x = 1.516 Mg m⁻³
Hall symbol: -P 1	Melting point: 512 K
a = 6.6907 (13) Å	Mo Kα radiation, λ = 0.71073 Å
b = 9.166 (2) Å	Cell parameters from 2461 reflections
c = 11.839 (2) Å	θ = 2.3–27.5°
α = 78.628 (8)°	µ = 0.12 mm⁻¹
β = 78.352 (9)°	T = 173 K
γ = 79.054 (9)°	Plate, colourless
V = 688.5 (2) Å³	0.28 × 0.22 × 0.12 mm

Data collection top

Rigaku Saturn724+ CCD diffractometer	3137 independent reflections
Radiation source: sealed tube	2864 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.042
ω scans at fixed χ = 45°	θ_max = 27.5°, θ_min = 3.2°
Absorption correction: multi-scan (CrystalClear; Rigaku, 2008)	h = −8→8
T_min = 0.680, T_max = 1.000	k = −11→11
8959 measured reflections	l = −15→15

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)] = 0.046	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.113	H-atom parameters constrained
S = 1.07	w = 1/[σ²(F_o²) + (0.0473P)² + 0.2684P] where P = (F_o² + 2F_c²)/3
3137 reflections	(Δ/σ)_max < 0.001
209 parameters	Δρ_max = 0.32 e Å⁻³
0 restraints	Δρ_min = −0.22 e Å⁻³

Crystal data top

C₁₇H₁₄O₆	γ = 79.054 (9)°
M_r = 314.28	V = 688.5 (2) Å³
Triclinic, P1	Z = 2
a = 6.6907 (13) Å	Mo Kα radiation
b = 9.166 (2) Å	µ = 0.12 mm⁻¹
c = 11.839 (2) Å	T = 173 K
α = 78.628 (8)°	0.28 × 0.22 × 0.12 mm
β = 78.352 (9)°

Data collection top

Rigaku Saturn724+ CCD diffractometer	3137 independent reflections
Absorption correction: multi-scan (CrystalClear; Rigaku, 2008)	2864 reflections with I > 2σ(I)
T_min = 0.680, T_max = 1.000	R_int = 0.042
8959 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.046	0 restraints
wR(F²) = 0.113	H-atom parameters constrained
S = 1.07	Δρ_max = 0.32 e Å⁻³
3137 reflections	Δρ_min = −0.22 e Å⁻³
209 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
O1	0.92938 (16)	0.39637 (11)	0.93311 (9)	0.0301 (3)
O2	0.66859 (17)	0.57336 (11)	0.88256 (10)	0.0354 (3)
O3	1.15083 (16)	0.18178 (12)	0.96436 (10)	0.0330 (3)
O4	0.49898 (16)	−0.15978 (12)	0.67925 (9)	0.0312 (3)
O5	0.27400 (16)	−0.18783 (12)	0.84664 (10)	0.0332 (3)
O6	0.75828 (19)	−0.09713 (14)	0.53681 (10)	0.0403 (3)
C1	0.7423 (2)	0.44344 (15)	0.89396 (12)	0.0257 (3)
C2	0.6609 (2)	0.30800 (14)	0.87438 (11)	0.0220 (3)
H2	0.5548	0.2806	0.9443	0.026*
C3	0.8484 (2)	0.18248 (15)	0.87829 (12)	0.0235 (3)
H3	0.8078	0.0875	0.9278	0.028*
C4	0.9938 (2)	0.24363 (15)	0.93188 (13)	0.0267 (3)
C5	0.9568 (2)	0.15432 (16)	0.75541 (13)	0.0255 (3)
H5A	1.0170	0.2446	0.7129	0.031*
H5B	1.0712	0.0687	0.7623	0.031*
C6	0.8083 (2)	0.11962 (15)	0.68574 (12)	0.0233 (3)
H6	0.8836	0.1187	0.6038	0.028*
C7	0.6239 (2)	0.24430 (14)	0.68056 (11)	0.0217 (3)
C8	0.5574 (2)	0.33563 (14)	0.76735 (11)	0.0217 (3)
C9	0.7444 (2)	−0.03861 (15)	0.73173 (12)	0.0243 (3)
H9	0.8682	−0.1090	0.7553	0.029*
C10	0.5642 (2)	−0.05583 (16)	0.83299 (12)	0.0263 (3)
H10A	0.6142	−0.1119	0.9050	0.032*
H10B	0.4887	0.0441	0.8484	0.032*
C11	0.6786 (2)	−0.09717 (16)	0.63586 (13)	0.0282 (3)
C12	0.4273 (2)	−0.14180 (15)	0.79467 (12)	0.0253 (3)
C13	0.5157 (2)	0.26953 (16)	0.58755 (12)	0.0267 (3)
H13	0.5581	0.2077	0.5286	0.032*
C14	0.3478 (2)	0.38295 (16)	0.57969 (13)	0.0298 (3)
H14	0.2769	0.3981	0.5154	0.036*
C15	0.2811 (2)	0.47547 (16)	0.66501 (13)	0.0280 (3)
C16	0.3867 (2)	0.44920 (15)	0.75866 (13)	0.0253 (3)
H16	0.3418	0.5100	0.8182	0.030*
C17	0.1005 (3)	0.60085 (19)	0.65557 (16)	0.0397 (4)
H17A	0.1385	0.6798	0.5899	0.060*
H17B	0.0630	0.6433	0.7282	0.060*
H17C	−0.0175	0.5611	0.6425	0.060*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0320 (6)	0.0239 (5)	0.0387 (6)	−0.0023 (4)	−0.0146 (4)	−0.0086 (4)
O2	0.0399 (6)	0.0225 (5)	0.0467 (7)	0.0026 (4)	−0.0148 (5)	−0.0122 (5)
O3	0.0293 (6)	0.0322 (6)	0.0406 (6)	−0.0015 (4)	−0.0170 (5)	−0.0054 (5)
O4	0.0339 (6)	0.0336 (6)	0.0306 (5)	−0.0099 (4)	−0.0074 (4)	−0.0095 (4)
O5	0.0295 (6)	0.0309 (6)	0.0399 (6)	−0.0061 (4)	−0.0068 (5)	−0.0052 (5)
O6	0.0437 (7)	0.0467 (7)	0.0346 (6)	−0.0114 (5)	0.0020 (5)	−0.0212 (5)
C1	0.0276 (7)	0.0240 (7)	0.0264 (7)	−0.0009 (5)	−0.0065 (5)	−0.0071 (5)
C2	0.0227 (6)	0.0206 (6)	0.0224 (6)	−0.0017 (5)	−0.0039 (5)	−0.0043 (5)
C3	0.0240 (7)	0.0196 (6)	0.0284 (7)	−0.0017 (5)	−0.0090 (5)	−0.0042 (5)
C4	0.0291 (7)	0.0235 (7)	0.0289 (7)	−0.0032 (5)	−0.0088 (6)	−0.0047 (5)
C5	0.0201 (6)	0.0248 (7)	0.0333 (7)	−0.0018 (5)	−0.0050 (5)	−0.0099 (6)
C6	0.0214 (6)	0.0232 (7)	0.0255 (6)	−0.0010 (5)	−0.0032 (5)	−0.0079 (5)
C7	0.0224 (6)	0.0194 (6)	0.0231 (6)	−0.0048 (5)	−0.0028 (5)	−0.0026 (5)
C8	0.0215 (6)	0.0196 (6)	0.0241 (6)	−0.0033 (5)	−0.0049 (5)	−0.0025 (5)
C9	0.0241 (7)	0.0206 (6)	0.0292 (7)	0.0011 (5)	−0.0072 (5)	−0.0085 (5)
C10	0.0310 (7)	0.0231 (7)	0.0265 (7)	−0.0044 (5)	−0.0087 (6)	−0.0044 (5)
C11	0.0280 (7)	0.0246 (7)	0.0331 (7)	−0.0012 (5)	−0.0050 (6)	−0.0105 (6)
C12	0.0265 (7)	0.0202 (6)	0.0290 (7)	0.0003 (5)	−0.0094 (5)	−0.0031 (5)
C13	0.0308 (7)	0.0253 (7)	0.0254 (7)	−0.0057 (6)	−0.0067 (6)	−0.0036 (5)
C14	0.0323 (8)	0.0283 (7)	0.0304 (7)	−0.0054 (6)	−0.0141 (6)	0.0012 (6)
C15	0.0247 (7)	0.0223 (7)	0.0360 (8)	−0.0018 (5)	−0.0088 (6)	−0.0001 (6)
C16	0.0247 (7)	0.0203 (6)	0.0307 (7)	−0.0018 (5)	−0.0050 (5)	−0.0050 (5)
C17	0.0317 (8)	0.0343 (8)	0.0505 (10)	0.0058 (7)	−0.0165 (7)	−0.0013 (7)

Geometric parameters (Å, º) top

O1—C1	1.3851 (17)	C6—H6	1.0000
O1—C4	1.3865 (17)	C7—C13	1.3956 (19)
O2—C1	1.1915 (17)	C7—C8	1.4027 (18)
O3—C4	1.1935 (17)	C8—C16	1.3970 (18)
O4—C12	1.3850 (17)	C9—C11	1.517 (2)
O4—C11	1.3905 (18)	C9—C10	1.526 (2)
O5—C12	1.1900 (18)	C9—H9	1.0000
O6—C11	1.1862 (18)	C10—C12	1.4991 (19)
C1—C2	1.5207 (19)	C10—H10A	0.9900
C2—C8	1.5200 (18)	C10—H10B	0.9900
C2—C3	1.5344 (18)	C13—C14	1.383 (2)
C2—H2	1.0000	C13—H13	0.9500
C3—C4	1.5031 (19)	C14—C15	1.397 (2)
C3—C5	1.5362 (19)	C14—H14	0.9500
C3—H3	1.0000	C15—C16	1.390 (2)
C5—C6	1.5244 (19)	C15—C17	1.507 (2)
C5—H5A	0.9900	C16—H16	0.9500
C5—H5B	0.9900	C17—H17A	0.9800
C6—C7	1.5165 (18)	C17—H17B	0.9800
C6—C9	1.5533 (19)	C17—H17C	0.9800

C1—O1—C4	110.69 (11)	C7—C8—C2	121.09 (12)
C12—O4—C11	110.64 (11)	C11—C9—C10	103.25 (11)
O2—C1—O1	120.19 (13)	C11—C9—C6	110.63 (12)
O2—C1—C2	130.17 (13)	C10—C9—C6	118.92 (11)
O1—C1—C2	109.62 (11)	C11—C9—H9	107.9
C8—C2—C1	114.64 (11)	C10—C9—H9	107.9
C8—C2—C3	116.61 (11)	C6—C9—H9	107.9
C1—C2—C3	103.25 (11)	C12—C10—C9	105.44 (11)
C8—C2—H2	107.3	C12—C10—H10A	110.7
C1—C2—H2	107.3	C9—C10—H10A	110.7
C3—C2—H2	107.3	C12—C10—H10B	110.7
C4—C3—C2	103.97 (11)	C9—C10—H10B	110.7
C4—C3—C5	108.12 (11)	H10A—C10—H10B	108.8
C2—C3—C5	112.08 (11)	O6—C11—O4	120.17 (13)
C4—C3—H3	110.8	O6—C11—C9	129.62 (14)
C2—C3—H3	110.8	O4—C11—C9	110.19 (12)
C5—C3—H3	110.8	O5—C12—O4	120.36 (13)
O3—C4—O1	120.54 (13)	O5—C12—C10	129.79 (13)
O3—C4—C3	129.34 (13)	O4—C12—C10	109.80 (12)
O1—C4—C3	109.98 (11)	C14—C13—C7	121.11 (13)
C6—C5—C3	111.80 (11)	C14—C13—H13	119.4
C6—C5—H5A	109.3	C7—C13—H13	119.4
C3—C5—H5A	109.3	C13—C14—C15	120.87 (13)
C6—C5—H5B	109.3	C13—C14—H14	119.6
C3—C5—H5B	109.3	C15—C14—H14	119.6
H5A—C5—H5B	107.9	C16—C15—C14	118.15 (13)
C7—C6—C5	110.47 (11)	C16—C15—C17	120.88 (14)
C7—C6—C9	112.62 (11)	C14—C15—C17	120.97 (14)
C5—C6—C9	112.35 (11)	C15—C16—C8	121.59 (13)
C7—C6—H6	107.0	C15—C16—H16	119.2
C5—C6—H6	107.0	C8—C16—H16	119.2
C9—C6—H6	107.0	C15—C17—H17A	109.5
C13—C7—C8	118.59 (12)	C15—C17—H17B	109.5
C13—C7—C6	119.62 (12)	H17A—C17—H17B	109.5
C8—C7—C6	121.79 (12)	C15—C17—H17C	109.5
C16—C8—C7	119.69 (13)	H17A—C17—H17C	109.5
C16—C8—C2	119.14 (12)	H17B—C17—H17C	109.5

C4—O1—C1—O2	−175.65 (13)	C3—C2—C8—C16	−179.58 (12)
C4—O1—C1—C2	5.59 (15)	C1—C2—C8—C7	124.46 (13)
O2—C1—C2—C8	40.1 (2)	C3—C2—C8—C7	3.66 (18)
O1—C1—C2—C8	−141.25 (12)	C7—C6—C9—C11	78.97 (14)
O2—C1—C2—C3	168.05 (15)	C5—C6—C9—C11	−155.52 (11)
O1—C1—C2—C3	−13.35 (14)	C7—C6—C9—C10	−40.22 (17)
C8—C2—C3—C4	141.97 (12)	C5—C6—C9—C10	85.29 (15)
C1—C2—C3—C4	15.30 (13)	C11—C9—C10—C12	8.01 (14)
C8—C2—C3—C5	25.43 (16)	C6—C9—C10—C12	130.94 (12)
C1—C2—C3—C5	−101.23 (12)	C12—O4—C11—O6	−177.29 (13)
C1—O1—C4—O3	−178.89 (13)	C12—O4—C11—C9	3.61 (15)
C1—O1—C4—C3	5.03 (15)	C10—C9—C11—O6	173.67 (15)
C2—C3—C4—O3	171.22 (15)	C6—C9—C11—O6	45.4 (2)
C5—C3—C4—O3	−69.50 (19)	C10—C9—C11—O4	−7.34 (15)
C2—C3—C4—O1	−13.15 (15)	C6—C9—C11—O4	−135.61 (11)
C5—C3—C4—O1	106.13 (13)	C11—O4—C12—O5	179.67 (12)
C4—C3—C5—C6	−169.56 (11)	C11—O4—C12—C10	1.92 (15)
C2—C3—C5—C6	−55.55 (15)	C9—C10—C12—O5	176.04 (14)
C3—C5—C6—C7	55.19 (15)	C9—C10—C12—O4	−6.49 (15)
C3—C5—C6—C9	−71.49 (14)	C8—C7—C13—C14	0.7 (2)
C5—C6—C7—C13	154.16 (12)	C6—C7—C13—C14	−179.52 (13)
C9—C6—C7—C13	−79.31 (15)	C7—C13—C14—C15	−0.2 (2)
C5—C6—C7—C8	−26.09 (17)	C13—C14—C15—C16	−0.7 (2)
C9—C6—C7—C8	100.44 (15)	C13—C14—C15—C17	178.93 (14)
C13—C7—C8—C16	−0.3 (2)	C14—C15—C16—C8	1.1 (2)
C6—C7—C8—C16	179.93 (12)	C17—C15—C16—C8	−178.53 (13)
C13—C7—C8—C2	176.43 (12)	C7—C8—C16—C15	−0.6 (2)
C6—C7—C8—C2	−3.3 (2)	C2—C8—C16—C15	−177.42 (12)
C1—C2—C8—C16	−58.78 (16)

Experimental details

Crystal data
Chemical formula	C₁₇H₁₄O₆
M_r	314.28
Crystal system, space group	Triclinic, P1
Temperature (K)	173
a, b, c (Å)	6.6907 (13), 9.166 (2), 11.839 (2)
α, β, γ (°)	78.628 (8), 78.352 (9), 79.054 (9)
V (Å³)	688.5 (2)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.12
Crystal size (mm)	0.28 × 0.22 × 0.12

Data collection
Diffractometer	Rigaku Saturn724+ CCD diffractometer
Absorption correction	Multi-scan (CrystalClear; Rigaku, 2008)
T_min, T_max	0.680, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	8959, 3137, 2864
R_int	0.042
(sin θ/λ)_max (Å⁻¹)	0.649

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.046, 0.113, 1.07
No. of reflections	3137
No. of parameters	209
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.32, −0.22

Computer programs: CrystalClear (Rigaku, 2008), SHELXS97 (Sheldrick, 2008), OLEX2 (Dolomanov et al., 2009), SHELXL97 (Sheldrick, 2008).

Acknowledgements

The authors are grateful to the National Natural Science Foundation of China for financial support. They also thank Dr Tong Lin Liang of ICCAS for the X-ray data collection.

References

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