3,3′-Dimeth­oxy-2,2′-[o-phenyl­enebis(nitrilo­methyl­idyne)]diphenol

Clegg, W.; Habibi, M.H.; Harrington, R.W.; Mokhtari, R.; Montazerozohori, M.

doi:10.1107/S160053680704826X

3,3′-Dimethoxy-2,2′-[o-phenylenebis(nitrilomethylidyne)]diphenol

M. H. Habibi, M. Montazerozohori, R. Mokhtari, R. W. Harrington and W. Clegg

The title Schiff base compound, C₁₉H₂₀N₂O₄, was synthesized by the reaction of o-phenylenediamine with 6-methoxysalicylaldehyde. The central benzene ring makes dihedral angles of 2.78 (5) and 73.98 (5)° with the two terminal phenol rings. Each methoxy group is coplanar with the attached phenol ring. The crystal structure is stabilized by intramolecular O—H

N and intermolecular C—H

O hydrogen bonds.

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Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S160053680704826X/xu2333sup1.cif Contains datablocks I, global
	Structure factor file (CIF format) https://doi.org/10.1107/S160053680704826X/xu2333Isup2.hkl Contains datablock I

CCDC reference: 667462

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Key indicators

Single-crystal X-ray study
T = 150 K
Mean (C-C) = 0.002 Å
R factor = 0.039
wR factor = 0.111
Data-to-parameter ratio = 16.0

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical .          ?
PLAT154_ALERT_1_C The su's on the Cell Angles are Equal  (x 10000)        100 Deg.
PLAT180_ALERT_3_C Check Cell Rounding: # of Values Ending with 0 =          3

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

   2 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
   1 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

Comment top

Schiff bases rank among the most versatile synthetic organic intermediates. They are reported to show a variety of biological activities including antifungal (Singh & Dash, 1988; More et al., 2001), antibacterial (Baseer et al., 2000; El-Masry et al., 2000; Kabeer et al., 2001) and anticancer (Kuzmin et al., 2000; Desai et al., 2001) among others. Recently we reported the structure of a copper(II) and nickel(II) complexes with the N,N'-bis(6-methoxysalicylidene)-1,3-diaminopropane ligand (Habibi et al., 2007a,b)·As an extension of our investigations of Schiff base ligands and complexes, the title compound (Fig. 1) was synthesized by the reaction of o-phenylenediamine with 6-methoxysalicylaldehyde, and its crystal structure is reported here.

The orientations of the C2–C7 and C16–C21 benzene rings respect to the o-phenylenediamine unit are indicated by the dihedral angles of 73.98 (5)and 2.78 (5)°, respectively. The C2–C7 and C16–C21 benzene rings makes the dihedral angle of 73.14 (5)°. The two methoxy groups are planarly attached to the C2–C7 and C16–C21 benzene rings·The intramolecular O—H···N interactions generate S(6) ring motifs (Table 1 and Fig. 2).

Related literature top

For general background, see: Baseer et al. (2000); Desai et al. (2001); El-Masry et al. (2000); Kabeer et al. (2001); Kuzmin et al. (2000); More et al. (2001); Singh & Dash (1988). For related structures, see: Habibi et al. (2007a,b).

Experimental top

The title compound was synthesized by adding 6-methoxysalicylaldehyde (0.304 g, 2 mmol) into a solution of o-phenylenediamine (0.108 g, 1 mmol) in ethanol (10 ml). The mixture was refluxed with stirring for 30 min. The resultant red solution was filtered. Orange block-shaped single crystals of (I) suitable for X-ray structure determination were formed after 3 days of slow evaporation of the solvent at room temperature.

Structure description top

Computing details top

Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT (Bruker, 2001); program(s) used to solve structure: SHELXTL (Sheldrick, 2005); program(s) used to refine structure: SHELXTL (Sheldrick, 2005); molecular graphics: DIAMOND (Brandenburg, 2007); software used to prepare material for publication: SHELXTL and local programs.

Figures top

	Fig. 1. The molecular structure of (I), showing 50% probability displacement ellipsoids and the atomic numbering.
	Fig. 2. The crystal packing of (I), hydrogen bonds were drawn as dash lines.

3,3'-Dimethoxy-2,2'-[1,2-phenylenebis(nitrilomethylidyne)]diphenol top

Crystal data top

C₂₂H₂₀N₂O₄	Z = 2
M_r = 376.40	F(000) = 396
Triclinic, P1	D_x = 1.387 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 8.3766 (9) Å	Cell parameters from 5073 reflections
b = 11.1515 (11) Å	θ = 2.3–28.3°
c = 11.2575 (12) Å	µ = 0.10 mm⁻¹
α = 101.848 (1)°	T = 150 K
β = 108.359 (1)°	Block, orange
γ = 107.077 (1)°	0.32 × 0.30 × 0.20 mm
V = 901.19 (16) Å³

Data collection top

Bruker SMART 1K CCD diffractometer	4197 independent reflections
Radiation source: sealed tube	3504 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.015
thin–slice ω scans	θ_max = 28.3°, θ_min = 2.0°
Absorption correction: multi-scan (SADABS; Sheldrick, 2007)	h = −11→11
T_min = 0.970, T_max = 0.981	k = −14→14
8089 measured reflections	l = −14→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)] = 0.039	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.111	H atoms treated by a mixture of independent and constrained refinement
S = 1.04	w = 1/[σ²(F_o²) + (0.0546P)² + 0.2872P] where P = (F_o² + 2F_c²)/3
4197 reflections	(Δ/σ)_max < 0.001
263 parameters	Δρ_max = 0.31 e Å⁻³
0 restraints	Δρ_min = −0.18 e Å⁻³

Crystal data top

C₂₂H₂₀N₂O₄	γ = 107.077 (1)°
M_r = 376.40	V = 901.19 (16) Å³
Triclinic, P1	Z = 2
a = 8.3766 (9) Å	Mo Kα radiation
b = 11.1515 (11) Å	µ = 0.10 mm⁻¹
c = 11.2575 (12) Å	T = 150 K
α = 101.848 (1)°	0.32 × 0.30 × 0.20 mm
β = 108.359 (1)°

Data collection top

Bruker SMART 1K CCD diffractometer	4197 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 2007)	3504 reflections with I > 2σ(I)
T_min = 0.970, T_max = 0.981	R_int = 0.015
8089 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.039	0 restraints
wR(F²) = 0.111	H atoms treated by a mixture of independent and constrained refinement
S = 1.04	Δρ_max = 0.31 e Å⁻³
4197 reflections	Δρ_min = −0.18 e Å⁻³
263 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	−0.13493 (13)	0.19435 (9)	0.03338 (10)	0.0361 (2)
O2	0.41326 (13)	0.32229 (10)	−0.03430 (10)	0.0335 (2)
H2	0.432 (3)	0.397 (2)	0.042 (2)	0.069 (6)*
O3	0.55943 (13)	0.25477 (9)	0.26963 (9)	0.0335 (2)
H3	0.547 (3)	0.332 (2)	0.284 (2)	0.070 (6)*
O4	1.01314 (12)	0.49961 (8)	0.70540 (8)	0.0257 (2)
N1	0.36681 (13)	0.46636 (10)	0.15216 (10)	0.0225 (2)
N2	0.61616 (14)	0.49466 (9)	0.38789 (10)	0.0229 (2)
C1	−0.31728 (19)	0.10418 (15)	−0.00296 (16)	0.0402 (4)
H1A	−0.3665	0.1384	0.0586	0.060*
H1B	−0.3169	0.0172	0.0008	0.060*
H1C	−0.3933	0.0951	−0.0932	0.060*
C2	0.24429 (17)	0.23396 (12)	−0.06730 (12)	0.0260 (3)
C3	0.1757 (2)	0.11749 (14)	−0.17425 (13)	0.0333 (3)
H3A	0.2470	0.1020	−0.2221	0.040*
C4	0.0033 (2)	0.02529 (13)	−0.20961 (14)	0.0370 (3)
H4A	−0.0414	−0.0546	−0.2812	0.044*
C5	−0.10797 (19)	0.04491 (13)	−0.14405 (14)	0.0342 (3)
H5A	−0.2267	−0.0200	−0.1708	0.041*
C6	−0.04092 (17)	0.16164 (12)	−0.03873 (13)	0.0273 (3)
C7	0.13665 (16)	0.25797 (11)	0.00215 (11)	0.0231 (2)
C8	0.20536 (16)	0.37949 (11)	0.11280 (11)	0.0218 (2)
H8A	0.1294	0.3946	0.1565	0.026*
C9	0.43040 (15)	0.58591 (11)	0.25858 (11)	0.0198 (2)
C10	0.36779 (17)	0.68650 (12)	0.24104 (12)	0.0249 (3)
H10A	0.2758	0.6735	0.1588	0.030*
C11	0.44001 (18)	0.80535 (12)	0.34372 (13)	0.0266 (3)
H11A	0.3969	0.8737	0.3319	0.032*
C12	0.57513 (17)	0.82492 (12)	0.46385 (13)	0.0268 (3)
H12A	0.6250	0.9069	0.5337	0.032*
C13	0.63754 (17)	0.72499 (12)	0.48213 (12)	0.0259 (3)
H13A	0.7293	0.7387	0.5648	0.031*
C14	0.56646 (15)	0.60432 (11)	0.37985 (11)	0.0201 (2)
C15	0.74570 (15)	0.49796 (11)	0.48910 (11)	0.0204 (2)
H15A	0.8125	0.5768	0.5636	0.024*
C16	0.78987 (16)	0.38175 (11)	0.48972 (12)	0.0208 (2)
C17	0.92887 (16)	0.38330 (12)	0.60199 (12)	0.0219 (2)
C18	0.97267 (17)	0.27272 (13)	0.60344 (13)	0.0276 (3)
H18A	1.0656	0.2743	0.6793	0.033*
C19	0.87784 (19)	0.15936 (13)	0.49159 (14)	0.0318 (3)
H19A	0.9081	0.0837	0.4919	0.038*
C20	0.74174 (19)	0.15375 (13)	0.38064 (14)	0.0320 (3)
H20A	0.6793	0.0751	0.3057	0.038*
C21	0.69577 (17)	0.26434 (12)	0.37869 (12)	0.0254 (3)
C22	1.14988 (18)	0.50459 (14)	0.82323 (13)	0.0320 (3)
H22A	1.2030	0.5937	0.8885	0.048*
H22B	1.2456	0.4841	0.8019	0.048*
H22C	1.0946	0.4394	0.8600	0.048*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0267 (5)	0.0295 (5)	0.0411 (6)	0.0010 (4)	0.0136 (4)	0.0044 (4)
O2	0.0281 (5)	0.0360 (5)	0.0310 (5)	0.0104 (4)	0.0130 (4)	0.0009 (4)
O3	0.0389 (5)	0.0245 (5)	0.0262 (5)	0.0141 (4)	0.0025 (4)	0.0009 (4)
O4	0.0261 (4)	0.0257 (4)	0.0222 (4)	0.0112 (4)	0.0052 (3)	0.0073 (3)
N1	0.0227 (5)	0.0216 (5)	0.0197 (5)	0.0082 (4)	0.0066 (4)	0.0034 (4)
N2	0.0259 (5)	0.0189 (5)	0.0229 (5)	0.0100 (4)	0.0079 (4)	0.0057 (4)
C1	0.0258 (7)	0.0371 (8)	0.0475 (9)	0.0011 (6)	0.0104 (6)	0.0168 (7)
C2	0.0265 (6)	0.0259 (6)	0.0226 (6)	0.0130 (5)	0.0050 (5)	0.0057 (5)
C3	0.0387 (7)	0.0321 (7)	0.0255 (6)	0.0203 (6)	0.0070 (5)	0.0019 (5)
C4	0.0428 (8)	0.0250 (6)	0.0280 (7)	0.0150 (6)	0.0002 (6)	−0.0018 (5)
C5	0.0304 (7)	0.0221 (6)	0.0331 (7)	0.0048 (5)	−0.0008 (5)	0.0046 (5)
C6	0.0265 (6)	0.0229 (6)	0.0267 (6)	0.0082 (5)	0.0047 (5)	0.0081 (5)
C7	0.0242 (6)	0.0203 (5)	0.0213 (5)	0.0091 (5)	0.0047 (5)	0.0066 (4)
C8	0.0222 (5)	0.0229 (6)	0.0202 (5)	0.0099 (4)	0.0070 (4)	0.0077 (4)
C9	0.0190 (5)	0.0190 (5)	0.0204 (5)	0.0057 (4)	0.0091 (4)	0.0047 (4)
C10	0.0254 (6)	0.0276 (6)	0.0241 (6)	0.0130 (5)	0.0092 (5)	0.0101 (5)
C11	0.0313 (6)	0.0216 (6)	0.0336 (7)	0.0141 (5)	0.0163 (5)	0.0114 (5)
C12	0.0286 (6)	0.0174 (5)	0.0296 (6)	0.0071 (5)	0.0109 (5)	0.0021 (5)
C13	0.0248 (6)	0.0212 (6)	0.0235 (6)	0.0073 (5)	0.0040 (5)	0.0021 (5)
C14	0.0206 (5)	0.0167 (5)	0.0221 (5)	0.0068 (4)	0.0086 (4)	0.0052 (4)
C15	0.0215 (5)	0.0183 (5)	0.0209 (5)	0.0069 (4)	0.0094 (4)	0.0052 (4)
C16	0.0224 (5)	0.0196 (5)	0.0234 (6)	0.0089 (4)	0.0117 (5)	0.0079 (4)
C17	0.0214 (5)	0.0225 (6)	0.0248 (6)	0.0085 (4)	0.0118 (5)	0.0095 (5)
C18	0.0268 (6)	0.0301 (6)	0.0334 (7)	0.0157 (5)	0.0136 (5)	0.0158 (5)
C19	0.0371 (7)	0.0253 (6)	0.0429 (8)	0.0194 (5)	0.0200 (6)	0.0137 (6)
C20	0.0384 (7)	0.0212 (6)	0.0344 (7)	0.0137 (5)	0.0134 (6)	0.0039 (5)
C21	0.0280 (6)	0.0219 (6)	0.0254 (6)	0.0105 (5)	0.0100 (5)	0.0061 (5)
C22	0.0303 (7)	0.0388 (7)	0.0244 (6)	0.0165 (6)	0.0052 (5)	0.0098 (5)

Geometric parameters (Å, º) top

O1—C1	1.4307 (16)	C8—H8A	0.9500
O1—C6	1.3646 (17)	C9—C10	1.3941 (16)
O2—H2	1.00 (2)	C9—C14	1.4043 (16)
O2—C2	1.3458 (16)	C10—H10A	0.9500
O3—H3	0.89 (2)	C10—C11	1.3850 (17)
O3—C21	1.3470 (15)	C11—H11A	0.9500
O4—C17	1.3639 (14)	C11—C12	1.3882 (18)
O4—C22	1.4318 (15)	C12—H12A	0.9500
N1—C8	1.2809 (15)	C12—C13	1.3878 (17)
N1—C9	1.4218 (14)	C13—H13A	0.9500
N2—C14	1.4133 (14)	C13—C14	1.3973 (16)
N2—C15	1.2874 (15)	C15—H15A	0.9500
C1—H1A	0.9800	C15—C16	1.4491 (15)
C1—H1B	0.9800	C16—C17	1.4162 (16)
C1—H1C	0.9800	C16—C21	1.4140 (16)
C2—C3	1.3965 (17)	C17—C18	1.3877 (16)
C2—C7	1.4127 (18)	C18—H18A	0.9500
C3—H3A	0.9500	C18—C19	1.3932 (19)
C3—C4	1.378 (2)	C19—H19A	0.9500
C4—H4A	0.9500	C19—C20	1.376 (2)
C4—C5	1.396 (2)	C20—H20A	0.9500
C5—H5A	0.9500	C20—C21	1.3979 (17)
C5—C6	1.3903 (18)	C22—H22A	0.9800
C6—C7	1.4162 (17)	C22—H22B	0.9800
C7—C8	1.4548 (16)	C22—H22C	0.9800

C1—O1—C6	118.19 (11)	C10—C11—H11A	119.9
H2—O2—C2	104.6 (12)	C10—C11—C12	120.24 (11)
H3—O3—C21	107.0 (14)	H11A—C11—C12	119.9
C17—O4—C22	117.29 (10)	C11—C12—H12A	119.9
C8—N1—C9	120.25 (10)	C11—C12—C13	120.15 (11)
C14—N2—C15	123.35 (10)	H12A—C12—C13	119.9
O1—C1—H1A	109.5	C12—C13—H13A	119.7
O1—C1—H1B	109.5	C12—C13—C14	120.52 (11)
O1—C1—H1C	109.5	H13A—C13—C14	119.7
H1A—C1—H1B	109.5	N2—C14—C9	115.63 (10)
H1A—C1—H1C	109.5	N2—C14—C13	125.54 (10)
H1B—C1—H1C	109.5	C9—C14—C13	118.80 (10)
O2—C2—C3	118.18 (12)	N2—C15—H15A	119.9
O2—C2—C7	121.52 (11)	N2—C15—C16	120.21 (10)
C3—C2—C7	120.29 (12)	H15A—C15—C16	119.9
C2—C3—H3A	120.4	C15—C16—C17	120.61 (10)
C2—C3—C4	119.26 (13)	C15—C16—C21	121.00 (11)
H3A—C3—C4	120.4	C17—C16—C21	118.39 (10)
C3—C4—H4A	118.8	O4—C17—C16	115.11 (10)
C3—C4—C5	122.41 (12)	O4—C17—C18	123.82 (11)
H4A—C4—C5	118.8	C16—C17—C18	121.07 (11)
C4—C5—H5A	120.8	C17—C18—H18A	120.6
C4—C5—C6	118.42 (13)	C17—C18—C19	118.77 (12)
H5A—C5—C6	120.8	H18A—C18—C19	120.6
O1—C6—C5	124.72 (12)	C18—C19—H19A	119.0
O1—C6—C7	114.34 (11)	C18—C19—C20	121.96 (12)
C5—C6—C7	120.94 (13)	H19A—C19—C20	119.0
C2—C7—C6	118.66 (11)	C19—C20—H20A	120.2
C2—C7—C8	120.96 (11)	C19—C20—C21	119.66 (12)
C6—C7—C8	120.38 (11)	H20A—C20—C21	120.2
N1—C8—C7	120.98 (11)	O3—C21—C16	121.63 (11)
N1—C8—H8A	119.5	O3—C21—C20	118.22 (11)
C7—C8—H8A	119.5	C16—C21—C20	120.15 (11)
N1—C9—C10	120.92 (10)	O4—C22—H22A	109.5
N1—C9—C14	118.57 (10)	O4—C22—H22B	109.5
C10—C9—C14	120.40 (10)	O4—C22—H22C	109.5
C9—C10—H10A	120.1	H22A—C22—H22B	109.5
C9—C10—C11	119.88 (11)	H22A—C22—H22C	109.5
H10A—C10—C11	120.1	H22B—C22—H22C	109.5

O2—C2—C3—C4	179.74 (12)	C12—C13—C14—C9	−0.25 (18)
C7—C2—C3—C4	−1.21 (19)	N1—C9—C14—N2	−5.56 (15)
C2—C3—C4—C5	1.4 (2)	N1—C9—C14—C13	176.05 (10)
C3—C4—C5—C6	−0.4 (2)	C10—C9—C14—N2	178.37 (10)
C1—O1—C6—C5	−1.49 (19)	C10—C9—C14—C13	−0.01 (17)
C1—O1—C6—C7	178.56 (11)	C15—N2—C14—C9	175.83 (11)
C4—C5—C6—O1	179.44 (12)	C15—N2—C14—C13	−5.91 (19)
C4—C5—C6—C7	−0.61 (19)	C14—N2—C15—C16	−179.49 (10)
O2—C2—C7—C6	179.21 (11)	N2—C15—C16—C17	−178.30 (11)
O2—C2—C7—C8	−0.27 (18)	N2—C15—C16—C21	1.73 (17)
C3—C2—C7—C6	0.20 (18)	C22—O4—C17—C16	177.64 (10)
C3—C2—C7—C8	−179.29 (11)	C22—O4—C17—C18	−2.32 (17)
O1—C6—C7—C2	−179.32 (11)	C15—C16—C17—O4	0.26 (16)
O1—C6—C7—C8	0.17 (16)	C15—C16—C17—C18	−179.77 (11)
C5—C6—C7—C2	0.72 (18)	C21—C16—C17—O4	−179.77 (10)
C5—C6—C7—C8	−179.79 (11)	C21—C16—C17—C18	0.20 (17)
C9—N1—C8—C7	178.62 (10)	O4—C17—C18—C19	−179.67 (11)
C2—C7—C8—N1	−1.70 (17)	C16—C17—C18—C19	0.37 (18)
C6—C7—C8—N1	178.82 (11)	C17—C18—C19—C20	−0.5 (2)
C8—N1—C9—C10	−73.58 (15)	C18—C19—C20—C21	0.0 (2)
C8—N1—C9—C14	110.38 (13)	C19—C20—C21—O3	−178.67 (12)
N1—C9—C10—C11	−175.99 (11)	C19—C20—C21—C16	0.6 (2)
C14—C9—C10—C11	−0.02 (17)	C15—C16—C21—O3	−1.47 (18)
C9—C10—C11—C12	0.30 (18)	C15—C16—C21—C20	179.29 (11)
C10—C11—C12—C13	−0.56 (19)	C17—C16—C21—O3	178.56 (11)
C11—C12—C13—C14	0.53 (19)	C17—C16—C21—C20	−0.68 (18)
C12—C13—C14—N2	−178.45 (11)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2···N1	1.00 (2)	1.65 (2)	2.5759 (14)	151.8 (19)
O3—H3···N2	0.89 (2)	1.75 (2)	2.5587 (13)	150 (2)
C8—H8A···O4ⁱ	0.95	2.55	3.4687 (17)	164

Symmetry code: (i) −x+1, −y+1, −z+1.

Experimental details

Crystal data
Chemical formula	C₂₂H₂₀N₂O₄
M_r	376.40
Crystal system, space group	Triclinic, P1
Temperature (K)	150
a, b, c (Å)	8.3766 (9), 11.1515 (11), 11.2575 (12)
α, β, γ (°)	101.848 (1), 108.359 (1), 107.077 (1)
V (Å³)	901.19 (16)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.10
Crystal size (mm)	0.32 × 0.30 × 0.20

Data collection
Diffractometer	Bruker SMART 1K CCD
Absorption correction	Multi-scan (SADABS; Sheldrick, 2007)
T_min, T_max	0.970, 0.981
No. of measured, independent and observed [I > 2σ(I)] reflections	8089, 4197, 3504
R_int	0.015
(sin θ/λ)_max (Å⁻¹)	0.667

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.039, 0.111, 1.04
No. of reflections	4197
No. of parameters	263
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.31, −0.18

Computer programs: SMART (Bruker, 2001), SAINT (Bruker, 2001), SHELXTL (Sheldrick, 2005), DIAMOND (Brandenburg, 2007), SHELXTL and local programs.