4a-Hydr­oxy-9-(3-nitrophen­yl)-3,4,4a,5,6,7,9,9a-octa­hydro-2H-xanthene-1,8-dione

Hua, G.; Xu, J.; Jiang, B.; Zhang, Y.; Tu, S.

doi:10.1107/S1600536805042194

4a-Hydroxy-9-(3-nitrophenyl)-3,4,4a,5,6,7,9,9a-octahydro-2H-xanthene-1,8-dione

G. Hua, J. Xu, B. Jiang, Y. Zhang and S. Tu

The title compound, C₁₉H₁₉NO₆, has been synthesized by the reaction of 3-nitrobenzaldehyde with 1,3-cyclohexanedione in glycol under microwave irradiation. The compound is an intermediate of the target product 9-(3-nitrophenyl)-3,4,6,7-tetrahydro-2H-xanthene-1,8(5H,9H)-dione. X-ray crystal-structure analysis reveals that the central hydropyran ring adopts a half-chair conformation.

Read article Similar articles

Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536805042194/rz6157sup1.cif Contains datablocks x050605f, I
	Structure factor file (CIF format) https://doi.org/10.1107/S1600536805042194/rz6157Isup2.hkl Contains datablock I

CCDC reference: 296725

checkCIF report

Key indicators

Single-crystal X-ray study
T = 294 K
Mean (C-C) = 0.004 Å
R factor = 0.058
wR factor = 0.138
Data-to-parameter ratio = 14.8

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT026_ALERT_3_C Ratio Observed / Unique Reflections too Low ....         44 Perc.
PLAT355_ALERT_3_C Long    O-H Bond (0.82A)   O1     -   H1     ...       1.01 Ang.

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

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

Comment top

Pyrans and fused pyrans are biologically interesting compounds with antibacterial activitiy (El-Agrody et al., 2000), antifungal activity (Ohira & Yatagai, 1993), antitumor activity (Mohr et al., 1975) and hypotensive effect (Tandon et al., 1991). Polyfuctionalized 4H-pyrans are the structural units of a number of natural products and are used as versatile synthons because of the inherent reactivity of the inbuilt pyran ring. 4H-Pyran rings can be transformed to pyridine systems related to pharmacologically important calcium antagonists of the DHP type (Ciller et al., 1985; Marugan et al., 1989; Gonzalez et al., 1992).

In the course of our studies aimed at developing new approaches for the synthesis of xanthone derivatives, we synthesized the title compound, (I), as an intermediate reaction product. Its structure is reported here.

The central O2/C1/C6/C7/C8/C13 hydropyran ring in (I) displays a half-chair conformation, with atoms C1 and C6 displaced from the mean plane by −0.374 (3) and 0.283 (3) Å, respectively (Fig. 1). The C1–C6 ring is in a sofa conformation, with atoms C1 and C4 deviating from the C2/C3/C5/C6 plane by −0.659 (3) and 0.614 (4) Å, respectively. The C8–C13 ring adopts a boat conformation, with atoms C8 and C11 displaced from the C9/C10/C12/C13 plane by 0.143 (3) and 0.628 (4) Å, respectively.

In the crystal structure, there is a strong O—H···O intermolecular hydrogen-bond interaction, stabilizing the structure (Table 1, Fig. 2).

Experimental top

The title compound was prepared by the reaction of 3-nitrobenzaldehyde (1 mmol) with 1,3-cyclohexanedione (2 mmol) in glycol under microwave irradiation. The reaction was completed in 4 min. Single crystals of (I) suitable for X-ray diffraction were obtained by slow evaporation of an ethanol solution (m.p. 492 K).

Computing details top

Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997a); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997a); molecular graphics: SHELXTL (Sheldrick, 1997b); software used to prepare material for publication: SHELXTL.

Figures top

	Fig. 1. The molecular structure (I), showing 30% probability displacement ellipsoids and the atom-numbering scheme.
	Fig. 2. Partial packing diagram for (I), viewed along the a axis. Dashed lines indicate hydrogen bonds.

4a-Hydroxy-9-(3-nitro-phenyl)-3,4,4a,5,6,7,9,9a-octahydro-2H-xanthene-1,8-dione top

Crystal data top

C₁₉H₁₉NO₆	F(000) = 752
M_r = 357.35	D_x = 1.355 Mg m⁻³
Monoclinic, P2₁/n	Melting point: 492 K K
Hall symbol: -P 2yn	Mo Kα radiation, λ = 0.71073 Å
a = 6.2983 (11) Å	Cell parameters from 1499 reflections
b = 12.869 (2) Å	θ = 2.5–24.3°
c = 21.619 (4) Å	µ = 0.10 mm⁻¹
β = 90.960 (4)°	T = 294 K
V = 1752.1 (5) Å³	Prism, colourless
Z = 4	0.22 × 0.18 × 0.06 mm

Data collection top

Bruker SMART CCD area-detector diffractometer	3530 independent reflections
Radiation source: fine-focus sealed tube	1536 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.082
ϕ and ω scans	θ_max = 26.3°, θ_min = 1.8°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −7→5
T_min = 0.970, T_max = 0.994	k = −14→16
9539 measured reflections	l = −24→26

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)] = 0.058	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.138	H atoms treated by a mixture of independent and constrained refinement
S = 0.94	w = 1/[σ²(F_o²) + (0.0535P)²] where P = (F_o² + 2F_c²)/3
3530 reflections	(Δ/σ)_max < 0.001
239 parameters	Δρ_max = 0.18 e Å⁻³
0 restraints	Δρ_min = −0.19 e Å⁻³

Crystal data top

C₁₉H₁₉NO₆	V = 1752.1 (5) Å³
M_r = 357.35	Z = 4
Monoclinic, P2₁/n	Mo Kα radiation
a = 6.2983 (11) Å	µ = 0.10 mm⁻¹
b = 12.869 (2) Å	T = 294 K
c = 21.619 (4) Å	0.22 × 0.18 × 0.06 mm
β = 90.960 (4)°

Data collection top

Bruker SMART CCD area-detector diffractometer	3530 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	1536 reflections with I > 2σ(I)
T_min = 0.970, T_max = 0.994	R_int = 0.082
9539 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.058	0 restraints
wR(F²) = 0.138	H atoms treated by a mixture of independent and constrained refinement
S = 0.94	Δρ_max = 0.18 e Å⁻³
3530 reflections	Δρ_min = −0.19 e Å⁻³
239 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	0.8223 (4)	0.37217 (15)	0.18106 (11)	0.0535 (7)
H1	0.848 (6)	0.439 (3)	0.204 (2)	0.119 (15)*
O2	0.4539 (3)	0.38226 (13)	0.18857 (10)	0.0491 (6)
O3	0.6032 (4)	0.04412 (15)	0.25377 (11)	0.0613 (7)
O4	0.9200 (4)	0.20673 (16)	0.05762 (11)	0.0616 (7)
O5	0.8997 (5)	−0.18122 (17)	0.09561 (14)	0.0881 (10)
O6	0.6440 (4)	−0.25602 (17)	0.04763 (15)	0.0953 (11)
N1	0.7198 (6)	−0.18198 (19)	0.07495 (15)	0.0598 (9)
C1	0.6319 (5)	0.37591 (19)	0.14704 (16)	0.0410 (8)
C2	0.6153 (6)	0.4710 (2)	0.10583 (17)	0.0548 (10)
H2A	0.4777	0.4719	0.0850	0.066*
H2B	0.6272	0.5333	0.1310	0.066*
C3	0.7886 (6)	0.4707 (2)	0.05814 (18)	0.0634 (11)
H3A	0.9251	0.4796	0.0789	0.076*
H3B	0.7676	0.5291	0.0303	0.076*
C4	0.7917 (6)	0.3703 (2)	0.02044 (17)	0.0600 (10)
H4A	0.6677	0.3678	−0.0067	0.072*
H4B	0.9169	0.3692	−0.0051	0.072*
C5	0.7930 (5)	0.2760 (2)	0.06244 (16)	0.0450 (9)
C6	0.6219 (5)	0.27558 (18)	0.11060 (14)	0.0361 (8)
H6	0.4846	0.2741	0.0886	0.043*
C7	0.6300 (5)	0.18076 (17)	0.15356 (14)	0.0344 (8)
H7	0.7780	0.1686	0.1663	0.041*
C8	0.5018 (5)	0.20157 (18)	0.21027 (14)	0.0369 (8)
C9	0.4888 (6)	0.1214 (2)	0.25756 (16)	0.0469 (9)
C10	0.3445 (6)	0.1366 (3)	0.31102 (18)	0.0694 (11)
H10A	0.4281	0.1583	0.3468	0.083*
H10B	0.2782	0.0708	0.3209	0.083*
C11	0.1724 (6)	0.2168 (3)	0.2982 (2)	0.0767 (12)
H11A	0.0957	0.2305	0.3359	0.092*
H11B	0.0724	0.1899	0.2676	0.092*
C12	0.2699 (6)	0.3176 (2)	0.27459 (17)	0.0586 (10)
H12A	0.1579	0.3641	0.2605	0.070*
H12B	0.3476	0.3517	0.3080	0.070*
C13	0.4160 (5)	0.2959 (2)	0.22272 (16)	0.0464 (9)
C14	0.5469 (4)	0.08390 (19)	0.12010 (14)	0.0339 (7)
C15	0.6707 (5)	−0.00347 (19)	0.11298 (14)	0.0383 (8)
H15	0.8092	−0.0051	0.1286	0.046*
C16	0.5865 (5)	−0.08853 (19)	0.08243 (15)	0.0410 (8)
C17	0.3828 (6)	−0.0902 (2)	0.05858 (16)	0.0525 (10)
H17	0.3299	−0.1484	0.0380	0.063*
C18	0.2601 (5)	−0.0031 (2)	0.06608 (16)	0.0515 (9)
H18	0.1215	−0.0020	0.0505	0.062*
C19	0.3407 (5)	0.0830 (2)	0.09648 (15)	0.0441 (9)
H19	0.2554	0.1413	0.1012	0.053*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0579 (16)	0.0384 (11)	0.0638 (18)	0.0002 (11)	−0.0138 (13)	−0.0135 (11)
O2	0.0607 (16)	0.0335 (10)	0.0532 (17)	0.0138 (11)	0.0066 (13)	0.0038 (10)
O3	0.0895 (19)	0.0378 (11)	0.0564 (18)	0.0131 (12)	−0.0045 (14)	0.0127 (11)
O4	0.0526 (15)	0.0575 (13)	0.075 (2)	0.0102 (13)	0.0097 (13)	−0.0003 (13)
O5	0.080 (2)	0.0553 (14)	0.128 (3)	0.0156 (15)	−0.019 (2)	−0.0257 (15)
O6	0.097 (2)	0.0494 (13)	0.140 (3)	−0.0147 (14)	0.0057 (19)	−0.0418 (16)
N1	0.068 (2)	0.0353 (14)	0.076 (3)	−0.0087 (16)	0.0138 (19)	−0.0097 (15)
C1	0.043 (2)	0.0303 (14)	0.050 (2)	0.0054 (15)	−0.0020 (18)	−0.0002 (15)
C2	0.069 (3)	0.0304 (15)	0.065 (3)	0.0013 (16)	0.000 (2)	0.0067 (16)
C3	0.074 (3)	0.0383 (17)	0.078 (3)	−0.0108 (18)	0.004 (2)	0.0141 (18)
C4	0.066 (3)	0.0498 (18)	0.064 (3)	−0.0132 (18)	0.008 (2)	0.0097 (18)
C5	0.042 (2)	0.0402 (17)	0.053 (3)	−0.0095 (17)	−0.0053 (18)	−0.0002 (17)
C6	0.0364 (19)	0.0310 (14)	0.041 (2)	0.0005 (14)	−0.0032 (16)	0.0006 (14)
C7	0.0363 (18)	0.0288 (13)	0.038 (2)	0.0007 (13)	−0.0034 (15)	−0.0016 (13)
C8	0.045 (2)	0.0304 (14)	0.035 (2)	−0.0012 (14)	−0.0079 (16)	0.0000 (14)
C9	0.063 (2)	0.0394 (16)	0.038 (2)	−0.0090 (17)	−0.0054 (18)	0.0026 (16)
C10	0.104 (3)	0.0516 (19)	0.053 (3)	−0.008 (2)	0.017 (2)	0.0077 (19)
C11	0.084 (3)	0.077 (2)	0.070 (3)	−0.002 (2)	0.029 (2)	−0.005 (2)
C12	0.069 (3)	0.057 (2)	0.050 (3)	0.0202 (19)	0.008 (2)	0.0008 (18)
C13	0.053 (2)	0.0418 (17)	0.044 (2)	0.0064 (16)	−0.0035 (18)	0.0017 (16)
C14	0.0343 (19)	0.0357 (14)	0.032 (2)	−0.0040 (14)	−0.0032 (15)	0.0026 (13)
C15	0.0394 (19)	0.0332 (14)	0.042 (2)	−0.0052 (15)	−0.0013 (16)	0.0029 (14)
C16	0.046 (2)	0.0315 (14)	0.045 (2)	−0.0071 (15)	0.0103 (17)	−0.0047 (14)
C17	0.061 (3)	0.0448 (17)	0.052 (3)	−0.0186 (18)	0.0021 (19)	−0.0055 (16)
C18	0.043 (2)	0.0586 (19)	0.053 (3)	−0.0130 (18)	−0.0067 (17)	−0.0057 (18)
C19	0.039 (2)	0.0414 (15)	0.051 (2)	−0.0028 (15)	−0.0029 (17)	0.0014 (15)

Geometric parameters (Å, º) top

O1—C1	1.397 (3)	C7—C14	1.529 (3)
O1—H1	1.00 (4)	C7—H7	0.9800
O2—C13	1.358 (3)	C8—C13	1.357 (4)
O2—C1	1.451 (4)	C8—C9	1.456 (4)
O3—C9	1.231 (3)	C9—C10	1.495 (5)
O4—C5	1.204 (3)	C10—C11	1.519 (5)
O5—N1	1.211 (3)	C10—H10A	0.9700
O6—N1	1.215 (3)	C10—H10B	0.9700
N1—C16	1.477 (4)	C11—C12	1.527 (4)
C1—C6	1.513 (4)	C11—H11A	0.9700
C1—C2	1.517 (4)	C11—H11B	0.9700
C2—C3	1.514 (5)	C12—C13	1.489 (5)
C2—H2A	0.9700	C12—H12A	0.9700
C2—H2B	0.9700	C12—H12B	0.9700
C3—C4	1.529 (4)	C14—C15	1.378 (3)
C3—H3A	0.9700	C14—C19	1.388 (4)
C3—H3B	0.9700	C15—C16	1.380 (4)
C4—C5	1.515 (4)	C15—H15	0.9300
C4—H4A	0.9700	C16—C17	1.375 (4)
C4—H4B	0.9700	C17—C18	1.373 (4)
C5—C6	1.511 (5)	C17—H17	0.9300
C6—C7	1.534 (4)	C18—C19	1.380 (4)
C6—H6	0.9800	C18—H18	0.9300
C7—C8	1.503 (4)	C19—H19	0.9300

C1—O1—H1	111 (2)	C13—C8—C7	122.8 (3)
C13—O2—C1	115.8 (2)	C9—C8—C7	118.9 (2)
O5—N1—O6	122.9 (3)	O3—C9—C8	119.1 (3)
O5—N1—C16	118.9 (3)	O3—C9—C10	121.4 (3)
O6—N1—C16	118.2 (3)	C8—C9—C10	119.5 (3)
O1—C1—O2	110.0 (3)	C9—C10—C11	112.9 (3)
O1—C1—C6	105.8 (2)	C9—C10—H10A	109.0
O2—C1—C6	110.1 (2)	C11—C10—H10A	109.0
O1—C1—C2	112.8 (2)	C9—C10—H10B	109.0
O2—C1—C2	105.8 (2)	C11—C10—H10B	109.0
C6—C1—C2	112.4 (3)	H10A—C10—H10B	107.8
C3—C2—C1	110.8 (3)	C10—C11—C12	110.4 (3)
C3—C2—H2A	109.5	C10—C11—H11A	109.6
C1—C2—H2A	109.5	C12—C11—H11A	109.6
C3—C2—H2B	109.5	C10—C11—H11B	109.6
C1—C2—H2B	109.5	C12—C11—H11B	109.6
H2A—C2—H2B	108.1	H11A—C11—H11B	108.1
C2—C3—C4	112.4 (3)	C13—C12—C11	110.4 (3)
C2—C3—H3A	109.1	C13—C12—H12A	109.6
C4—C3—H3A	109.1	C11—C12—H12A	109.6
C2—C3—H3B	109.1	C13—C12—H12B	109.6
C4—C3—H3B	109.1	C11—C12—H12B	109.6
H3A—C3—H3B	107.9	H12A—C12—H12B	108.1
C5—C4—C3	110.9 (3)	C8—C13—O2	123.4 (3)
C5—C4—H4A	109.5	C8—C13—C12	124.8 (3)
C3—C4—H4A	109.5	O2—C13—C12	111.8 (2)
C5—C4—H4B	109.5	C15—C14—C19	118.6 (2)
C3—C4—H4B	109.5	C15—C14—C7	121.9 (2)
H4A—C4—H4B	108.0	C19—C14—C7	119.5 (2)
O4—C5—C6	122.6 (3)	C14—C15—C16	119.2 (3)
O4—C5—C4	122.6 (3)	C14—C15—H15	120.4
C6—C5—C4	114.8 (3)	C16—C15—H15	120.4
C5—C6—C1	109.3 (2)	C17—C16—C15	122.7 (3)
C5—C6—C7	113.8 (2)	C17—C16—N1	118.4 (3)
C1—C6—C7	111.3 (3)	C15—C16—N1	118.9 (3)
C5—C6—H6	107.4	C18—C17—C16	117.8 (3)
C1—C6—H6	107.4	C18—C17—H17	121.1
C7—C6—H6	107.4	C16—C17—H17	121.1
C8—C7—C14	110.3 (2)	C17—C18—C19	120.5 (3)
C8—C7—C6	109.8 (2)	C17—C18—H18	119.7
C14—C7—C6	110.8 (2)	C19—C18—H18	119.7
C8—C7—H7	108.6	C18—C19—C14	121.1 (3)
C14—C7—H7	108.6	C18—C19—H19	119.4
C6—C7—H7	108.6	C14—C19—H19	119.4
C13—C8—C9	117.9 (3)

C13—O2—C1—O1	−68.8 (3)	C7—C8—C9—C10	−173.8 (3)
C13—O2—C1—C6	47.5 (3)	O3—C9—C10—C11	−162.6 (3)
C13—O2—C1—C2	169.2 (2)	C8—C9—C10—C11	20.1 (4)
O1—C1—C2—C3	62.3 (4)	C9—C10—C11—C12	−51.6 (4)
O2—C1—C2—C3	−177.5 (3)	C10—C11—C12—C13	50.3 (4)
C6—C1—C2—C3	−57.3 (4)	C9—C8—C13—O2	166.4 (3)
C1—C2—C3—C4	54.2 (4)	C7—C8—C13—O2	−6.4 (4)
C2—C3—C4—C5	−50.8 (4)	C9—C8—C13—C12	−13.9 (4)
C3—C4—C5—O4	−129.0 (3)	C7—C8—C13—C12	173.4 (3)
C3—C4—C5—C6	51.3 (4)	C1—O2—C13—C8	−14.8 (4)
O4—C5—C6—C1	126.9 (3)	C1—O2—C13—C12	165.4 (3)
C4—C5—C6—C1	−53.4 (3)	C11—C12—C13—C8	−18.7 (5)
O4—C5—C6—C7	1.7 (4)	C11—C12—C13—O2	161.1 (3)
C4—C5—C6—C7	−178.5 (2)	C8—C7—C14—C15	−117.3 (3)
O1—C1—C6—C5	−67.8 (3)	C6—C7—C14—C15	120.9 (3)
O2—C1—C6—C5	173.4 (2)	C8—C7—C14—C19	62.2 (3)
C2—C1—C6—C5	55.7 (4)	C6—C7—C14—C19	−59.6 (4)
O1—C1—C6—C7	58.8 (3)	C19—C14—C15—C16	0.4 (4)
O2—C1—C6—C7	−60.1 (3)	C7—C14—C15—C16	179.9 (3)
C2—C1—C6—C7	−177.7 (3)	C14—C15—C16—C17	−0.1 (5)
C5—C6—C7—C8	163.1 (2)	C14—C15—C16—N1	−180.0 (3)
C1—C6—C7—C8	39.0 (3)	O5—N1—C16—C17	179.8 (3)
C5—C6—C7—C14	−74.9 (3)	O6—N1—C16—C17	0.5 (5)
C1—C6—C7—C14	161.1 (3)	O5—N1—C16—C15	−0.3 (5)
C14—C7—C8—C13	−129.4 (3)	O6—N1—C16—C15	−179.6 (3)
C6—C7—C8—C13	−7.1 (4)	C15—C16—C17—C18	−0.2 (5)
C14—C7—C8—C9	57.9 (3)	N1—C16—C17—C18	179.7 (3)
C6—C7—C8—C9	−179.8 (2)	C16—C17—C18—C19	0.2 (5)
C13—C8—C9—O3	−164.2 (3)	C17—C18—C19—C14	0.1 (5)
C7—C8—C9—O3	8.9 (4)	C15—C14—C19—C18	−0.4 (5)
C13—C8—C9—C10	13.1 (4)	C7—C14—C19—C18	−179.9 (3)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···O3ⁱ	1.00 (4)	1.66 (4)	2.661 (3)	175 (4)

Symmetry code: (i) −x+3/2, y+1/2, −z+1/2.

Experimental details

Crystal data
Chemical formula	C₁₉H₁₉NO₆
M_r	357.35
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	294
a, b, c (Å)	6.2983 (11), 12.869 (2), 21.619 (4)
β (°)	90.960 (4)
V (Å³)	1752.1 (5)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.10
Crystal size (mm)	0.22 × 0.18 × 0.06

Data collection
Diffractometer	Bruker SMART CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.970, 0.994
No. of measured, independent and observed [I > 2σ(I)] reflections	9539, 3530, 1536
R_int	0.082
(sin θ/λ)_max (Å⁻¹)	0.624

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.058, 0.138, 0.94
No. of reflections	3530
No. of parameters	239
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.18, −0.19

Computer programs: SMART (Bruker, 1998), SAINT (Bruker, 1999), SAINT, SHELXS97 (Sheldrick, 1997a), SHELXL97 (Sheldrick, 1997a), SHELXTL (Sheldrick, 1997b), SHELXTL.