3-(4-Bromo­phenyl­sulfin­yl)-2,5,7-trimethyl-1-benzofuran

Choi, H.D.; Seo, P.J.; Lee, U.

doi:10.1107/S1600536812001523

organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 68| Part 2| February 2012| Page o482

doi:10.1107/S1600536812001523

Open

access

3-(4-Bromophenylsulfinyl)-2,5,7-trimethyl-1-benzofuran

Hong Dae Choi,^a Pil Ja Seo ^a and Uk Lee ^b ^*

^aDepartment of Chemistry, Dongeui University, San 24 Kaya-dong Busanjin-gu, Busan 614-714, Republic of Korea, and ^bDepartment of Chemistry, Pukyong National University, 599-1 Daeyeon 3-dong, Nam-gu, Busan 608-737, Republic of Korea
^*Correspondence e-mail: uklee@pknu.ac.kr

(Received 10 January 2012; accepted 13 January 2012; online 21 January 2012)

In the title compound, C₁₇H₁₅BrO₂S, the 4-bromophenyl ring makes a dihedral angle of 87.78 (5)° with the mean plane of the benzofuran fragment. In the crystal, molecules are linked by weak C—H⋯O hydrogen bonds, and by weak intermolecular C—S⋯π [3.399 (2) Å] and C—Br⋯π [3.797 (2) and 3.757 (2) Å] interactions.

Related literature

For background information and the crystal structures of related compounds, see: Choi et al. (2010a ,b ).

Experimental

Crystal data

C₁₇H₁₅BrO₂S
M_r = 363.26
Triclinic, $[P \overline 1]$
a = 6.1034 (1) Å
b = 10.2278 (2) Å
c = 12.6731 (2) Å
α = 84.586 (1)°
β = 79.419 (1)°
γ = 85.730 (1)°
V = 772.87 (2) Å³
Z = 2
Mo Kα radiation
μ = 2.80 mm⁻¹
T = 173 K
0.37 × 0.34 × 0.25 mm

Data collection

Bruker SMART APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ) T_min = 0.474, T_max = 0.746
14146 measured reflections
3826 independent reflections
3319 reflections with I > 2σ(I)
R_int = 0.036

Refinement

R[F² > 2σ(F²)] = 0.032
wR(F²) = 0.086
S = 1.06
3826 reflections
193 parameters
H-atom parameters constrained
Δρ_max = 0.46 e Å⁻³
Δρ_min = −0.83 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C13—H13⋯O2ⁱ	0.95	2.50	3.233 (2)	134
Symmetry code: (i) -x+2, -y+1, -z+1.

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); 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 (Farrugia, 1997 ) and DIAMOND (Brandenburg, 1998 ); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536812001523/pv2507sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536812001523/pv2507Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536812001523/pv2507Isup3.cml

checkCIF report

Comment top

As a part of our continuing study of 2,5,7-trimethyl-1-benzofuran derivatives containing 3-(4-fluorophenylsulfinyl) (Choi et al., 2010a) and 3-(4-chlorophenylsufinyl) (Choi et al., 2010b) substituents, we report herein the crystal structure of the title compound.

In the title molecule (Fig. 1), the benzofuran unit is essentially planar, with a mean deviation of 0.007 (1) Å from the least-squares plane defined by the nine constituent atoms. The dihedral angle between the 4-bromophenyl ring and the mean plane of the benzofurn fragment is 87.78 (5)°. The crystal packing (Fig. 2) is stabilized by weak intermolecular C13—H13···O2 hydrogen bonds (Table 1). The crystal packing is further stabilized by intermolecular C15—Br1···π interactions between the bromine atom and the benzene rings of a neighbouring molecule with Br1···Cg1ⁱⁱⁱ and Br1···Cg2ⁱⁱⁱ being 3.757 (2) and 3.797 (2) Å, respectively. (Cg1 and Cg2 are the centroid of the C12–C17 and C2–C7 benzene rings, respectively.) In addition, there is a weak intermolecular S···π interaction between the sulfur and the centroid of the benzene ring (C12–C17) of an adjacent molecule, with S1···Cg1ⁱⁱ 3.399 (2) Å.

Related literature top

For background information and the crystal structures of related compounds, see: Choi et al. (2010a,b).

Experimental top

77% 3-Chloroperoxybenzoic acid (224 mg, 0.9 mmol) was added in small portions to a stirred solution of 3-(4-bromophenylsulfanyl)-2,5,7-trimethyl-1-benzofuran (312 mg, 0.9 mmol) in dichloromethane (40 mL) at 273 K. After being stirred at room temperature for 4 h, the mixture was washed with saturated sodium bicarbonate solution and the organic layer was separated, dried over magnesium sulfate, filtered and concentrated at reduced pressure. The residue was purified by column chromatography (hexane–ethyl acetate, 2:1 v/v) to afford the title compound as a colorless solid [yield 71%, m.p. 431–432 K; R_f = 0.53 (hexane-ethyl acetate, 2:1 v/v)]. Single crystals suitable for X-ray diffraction were prepared by slow evaporation of a solution of the title compound in ethyl acetate at room temperature.

Computing details top

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 1998); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. The molecular structure of the title compound with the atom numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are presented as small spheres of arbitrary radii.
	Fig. 2. A view of the C—H···O, C—S···π and C—Br···π interactions (dotted lines) in the crystal structure of the title compound. H atoms non-participating in hydrogen-bonding were omitted for clarity. [Symmetry codes: (i) - x + 2, - y + 1, - z + 1; (ii) - x + 1, - y + 1, - z + 1; (iii) - x + 1, - y + 2, - z + 1.]

3-(4-Bromophenylsulfinyl)-2,5,7-trimethyl-1-benzofuran top

Crystal data top

C₁₇H₁₅BrO₂S	Z = 2
M_r = 363.26	F(000) = 368
Triclinic, P1	D_x = 1.561 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 6.1034 (1) Å	Cell parameters from 8427 reflections
b = 10.2278 (2) Å	θ = 2.5–28.2°
c = 12.6731 (2) Å	µ = 2.80 mm⁻¹
α = 84.586 (1)°	T = 173 K
β = 79.419 (1)°	Block, colourless
γ = 85.730 (1)°	0.37 × 0.34 × 0.25 mm
V = 772.87 (2) Å³

Data collection top

Bruker SMART APEXII CCD diffractometer	3826 independent reflections
Radiation source: rotating anode	3319 reflections with I > 2σ(I)
Graphite multilayer monochromator	R_int = 0.036
Detector resolution: 10.0 pixels mm^-1	θ_max = 28.3°, θ_min = 1.6°
ϕ and ω scans	h = −8→8
Absorption correction: multi-scan (SADABS; Bruker, 2009)	k = −13→13
T_min = 0.474, T_max = 0.746	l = −16→16
14146 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)] = 0.032	Hydrogen site location: difference Fourier map
wR(F²) = 0.086	H-atom parameters constrained
S = 1.06	w = 1/[σ²(F_o²) + (0.0446P)² + 0.243P] where P = (F_o² + 2F_c²)/3
3826 reflections	(Δ/σ)_max = 0.001
193 parameters	Δρ_max = 0.46 e Å⁻³
0 restraints	Δρ_min = −0.83 e Å⁻³

Crystal data top

C₁₇H₁₅BrO₂S	γ = 85.730 (1)°
M_r = 363.26	V = 772.87 (2) Å³
Triclinic, P1	Z = 2
a = 6.1034 (1) Å	Mo Kα radiation
b = 10.2278 (2) Å	µ = 2.80 mm⁻¹
c = 12.6731 (2) Å	T = 173 K
α = 84.586 (1)°	0.37 × 0.34 × 0.25 mm
β = 79.419 (1)°

Data collection top

Bruker SMART APEXII CCD diffractometer	3826 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2009)	3319 reflections with I > 2σ(I)
T_min = 0.474, T_max = 0.746	R_int = 0.036
14146 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.032	0 restraints
wR(F²) = 0.086	H-atom parameters constrained
S = 1.06	Δρ_max = 0.46 e Å⁻³
3826 reflections	Δρ_min = −0.83 e Å⁻³
193 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
Br1	0.40055 (4)	0.990460 (19)	0.338480 (16)	0.04068 (9)
S1	0.60888 (8)	0.48980 (4)	0.65970 (3)	0.02498 (11)
O1	0.2929 (2)	0.59852 (12)	0.94015 (10)	0.0265 (3)
O2	0.8568 (2)	0.47089 (14)	0.64796 (11)	0.0343 (3)
C1	0.5094 (3)	0.56250 (17)	0.78141 (14)	0.0237 (4)
C2	0.6083 (3)	0.66325 (16)	0.82636 (14)	0.0237 (4)
C3	0.7953 (3)	0.73737 (17)	0.79577 (15)	0.0272 (4)
H3	0.8927	0.7269	0.7291	0.033*
C4	0.8367 (3)	0.82671 (18)	0.86439 (16)	0.0306 (4)
C5	0.6874 (4)	0.84262 (18)	0.96147 (16)	0.0329 (4)
H5	0.7167	0.9058	1.0067	0.039*
C6	0.4990 (3)	0.77049 (18)	0.99471 (14)	0.0297 (4)
C7	0.4683 (3)	0.68124 (17)	0.92437 (14)	0.0250 (4)
C8	0.3247 (3)	0.52683 (17)	0.85186 (14)	0.0249 (4)
C9	1.0408 (4)	0.9067 (2)	0.8340 (2)	0.0417 (5)
H9A	1.1561	0.8592	0.7851	0.063*
H9B	1.0982	0.9209	0.8990	0.063*
H9C	1.0006	0.9918	0.7980	0.063*
C10	0.3388 (4)	0.7868 (2)	1.09857 (16)	0.0422 (6)
H10A	0.1892	0.8123	1.0831	0.063*
H10B	0.3879	0.8553	1.1366	0.063*
H10C	0.3348	0.7035	1.1437	0.063*
C11	0.1536 (3)	0.43163 (19)	0.85082 (16)	0.0318 (4)
H11A	0.0141	0.4795	0.8386	0.048*
H11B	0.1275	0.3789	0.9202	0.048*
H11C	0.2061	0.3736	0.7930	0.048*
C13	0.7261 (3)	0.68142 (19)	0.49533 (15)	0.0277 (4)
H13	0.8740	0.6436	0.4918	0.033*
C12	0.5531 (3)	0.63048 (17)	0.57012 (14)	0.0232 (4)
C14	0.6811 (4)	0.78872 (19)	0.42530 (15)	0.0311 (4)
H14	0.7981	0.8255	0.3736	0.037*
C15	0.4645 (4)	0.84151 (18)	0.43155 (15)	0.0283 (4)
C16	0.2898 (3)	0.78812 (19)	0.50419 (16)	0.0309 (4)
H16	0.1415	0.8247	0.5064	0.037*
C17	0.3341 (3)	0.68074 (19)	0.57347 (16)	0.0303 (4)
H17	0.2160	0.6416	0.6229	0.036*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Br1	0.05809 (17)	0.03134 (12)	0.03613 (13)	−0.00576 (10)	−0.01923 (11)	0.00288 (8)
S1	0.0259 (2)	0.0250 (2)	0.0236 (2)	0.00246 (17)	−0.00289 (18)	−0.00540 (16)
O1	0.0265 (7)	0.0282 (6)	0.0229 (6)	−0.0006 (5)	0.0002 (5)	−0.0031 (5)
O2	0.0269 (7)	0.0430 (8)	0.0315 (7)	0.0107 (6)	−0.0044 (6)	−0.0077 (6)
C1	0.0244 (9)	0.0237 (8)	0.0222 (8)	0.0019 (7)	−0.0029 (7)	−0.0025 (6)
C2	0.0236 (9)	0.0224 (8)	0.0247 (8)	0.0032 (7)	−0.0050 (7)	−0.0012 (6)
C3	0.0227 (9)	0.0264 (8)	0.0314 (9)	0.0018 (7)	−0.0033 (7)	−0.0015 (7)
C4	0.0292 (10)	0.0237 (8)	0.0410 (11)	−0.0006 (7)	−0.0136 (8)	0.0012 (7)
C5	0.0439 (12)	0.0239 (8)	0.0347 (10)	0.0021 (8)	−0.0171 (9)	−0.0054 (7)
C6	0.0394 (12)	0.0252 (8)	0.0252 (9)	0.0047 (8)	−0.0093 (8)	−0.0037 (7)
C7	0.0273 (10)	0.0225 (8)	0.0245 (8)	0.0015 (7)	−0.0046 (7)	−0.0012 (6)
C8	0.0253 (9)	0.0248 (8)	0.0237 (8)	0.0016 (7)	−0.0037 (7)	−0.0010 (6)
C9	0.0341 (12)	0.0329 (10)	0.0608 (14)	−0.0058 (9)	−0.0138 (10)	−0.0044 (9)
C10	0.0604 (16)	0.0365 (11)	0.0277 (10)	0.0027 (10)	−0.0013 (10)	−0.0096 (8)
C11	0.0286 (10)	0.0324 (9)	0.0344 (10)	−0.0059 (8)	−0.0049 (8)	−0.0003 (8)
C13	0.0216 (9)	0.0333 (9)	0.0281 (9)	−0.0024 (7)	−0.0022 (7)	−0.0067 (7)
C12	0.0232 (9)	0.0261 (8)	0.0211 (8)	−0.0014 (7)	−0.0039 (7)	−0.0057 (6)
C14	0.0318 (11)	0.0343 (10)	0.0271 (9)	−0.0096 (8)	−0.0021 (8)	−0.0014 (7)
C15	0.0367 (11)	0.0255 (8)	0.0257 (9)	−0.0038 (8)	−0.0118 (8)	−0.0033 (7)
C16	0.0251 (10)	0.0344 (10)	0.0342 (10)	0.0017 (8)	−0.0091 (8)	−0.0028 (8)
C17	0.0229 (10)	0.0354 (10)	0.0300 (9)	−0.0012 (8)	0.0005 (8)	−0.0006 (8)

Geometric parameters (Å, º) top

Br1—C15	1.8988 (19)	C9—H9A	0.9800
S1—O2	1.4929 (15)	C9—H9B	0.9800
S1—C1	1.7623 (17)	C9—H9C	0.9800
S1—C12	1.7989 (18)	C10—H10A	0.9800
O1—C8	1.372 (2)	C10—H10B	0.9800
O1—C7	1.388 (2)	C10—H10C	0.9800
C1—C8	1.353 (3)	C11—H11A	0.9800
C1—C2	1.442 (3)	C11—H11B	0.9800
C2—C7	1.392 (2)	C11—H11C	0.9800
C2—C3	1.392 (3)	C13—C12	1.381 (3)
C3—C4	1.386 (3)	C13—C14	1.389 (3)
C3—H3	0.9500	C13—H13	0.9500
C4—C5	1.405 (3)	C12—C17	1.390 (3)
C4—C9	1.512 (3)	C14—C15	1.382 (3)
C5—C6	1.391 (3)	C14—H14	0.9500
C5—H5	0.9500	C15—C16	1.383 (3)
C6—C7	1.380 (3)	C16—C17	1.382 (3)
C6—C10	1.504 (3)	C16—H16	0.9500
C8—C11	1.482 (3)	C17—H17	0.9500

O2—S1—C1	107.54 (9)	H9A—C9—H9C	109.5
O2—S1—C12	106.52 (9)	H9B—C9—H9C	109.5
C1—S1—C12	97.22 (8)	C6—C10—H10A	109.5
C8—O1—C7	106.40 (13)	C6—C10—H10B	109.5
C8—C1—C2	107.98 (15)	H10A—C10—H10B	109.5
C8—C1—S1	124.04 (14)	C6—C10—H10C	109.5
C2—C1—S1	127.94 (14)	H10A—C10—H10C	109.5
C7—C2—C3	119.24 (17)	H10B—C10—H10C	109.5
C7—C2—C1	104.52 (16)	C8—C11—H11A	109.5
C3—C2—C1	136.24 (16)	C8—C11—H11B	109.5
C4—C3—C2	118.80 (17)	H11A—C11—H11B	109.5
C4—C3—H3	120.6	C8—C11—H11C	109.5
C2—C3—H3	120.6	H11A—C11—H11C	109.5
C3—C4—C5	119.54 (18)	H11B—C11—H11C	109.5
C3—C4—C9	119.84 (19)	C12—C13—C14	119.09 (18)
C5—C4—C9	120.62 (19)	C12—C13—H13	120.5
C6—C5—C4	123.30 (18)	C14—C13—H13	120.5
C6—C5—H5	118.3	C13—C12—C17	121.34 (17)
C4—C5—H5	118.3	C13—C12—S1	119.43 (14)
C7—C6—C5	114.68 (17)	C17—C12—S1	119.12 (14)
C7—C6—C10	121.73 (19)	C15—C14—C13	119.36 (18)
C5—C6—C10	123.59 (18)	C15—C14—H14	120.3
C6—C7—O1	125.11 (16)	C13—C14—H14	120.3
C6—C7—C2	124.42 (18)	C14—C15—C16	121.62 (18)
O1—C7—C2	110.46 (16)	C14—C15—Br1	119.99 (15)
C1—C8—O1	110.62 (16)	C16—C15—Br1	118.39 (15)
C1—C8—C11	133.50 (17)	C17—C16—C15	119.08 (18)
O1—C8—C11	115.86 (15)	C17—C16—H16	120.5
C4—C9—H9A	109.5	C15—C16—H16	120.5
C4—C9—H9B	109.5	C16—C17—C12	119.41 (18)
H9A—C9—H9B	109.5	C16—C17—H17	120.3
C4—C9—H9C	109.5	C12—C17—H17	120.3

O2—S1—C1—C8	−137.92 (16)	C1—C2—C7—C6	−179.37 (17)
C12—S1—C1—C8	112.17 (17)	C3—C2—C7—O1	−179.85 (15)
O2—S1—C1—C2	39.33 (18)	C1—C2—C7—O1	−0.31 (19)
C12—S1—C1—C2	−70.58 (17)	C2—C1—C8—O1	0.7 (2)
C8—C1—C2—C7	−0.3 (2)	S1—C1—C8—O1	178.45 (12)
S1—C1—C2—C7	−177.85 (14)	C2—C1—C8—C11	178.9 (2)
C8—C1—C2—C3	179.2 (2)	S1—C1—C8—C11	−3.4 (3)
S1—C1—C2—C3	1.6 (3)	C7—O1—C8—C1	−0.92 (19)
C7—C2—C3—C4	0.3 (3)	C7—O1—C8—C11	−179.41 (15)
C1—C2—C3—C4	−179.09 (19)	C14—C13—C12—C17	2.9 (3)
C2—C3—C4—C5	−1.5 (3)	C14—C13—C12—S1	178.98 (14)
C2—C3—C4—C9	178.93 (18)	O2—S1—C12—C13	11.31 (17)
C3—C4—C5—C6	1.5 (3)	C1—S1—C12—C13	122.07 (15)
C9—C4—C5—C6	−178.92 (19)	O2—S1—C12—C17	−172.47 (15)
C4—C5—C6—C7	−0.2 (3)	C1—S1—C12—C17	−61.72 (17)
C4—C5—C6—C10	179.87 (19)	C12—C13—C14—C15	−0.4 (3)
C5—C6—C7—O1	179.99 (16)	C13—C14—C15—C16	−1.6 (3)
C10—C6—C7—O1	−0.1 (3)	C13—C14—C15—Br1	178.71 (14)
C5—C6—C7—C2	−1.1 (3)	C14—C15—C16—C17	1.2 (3)
C10—C6—C7—C2	178.82 (18)	Br1—C15—C16—C17	−179.15 (15)
C8—O1—C7—C6	179.80 (17)	C15—C16—C17—C12	1.3 (3)
C8—O1—C7—C2	0.75 (19)	C13—C12—C17—C16	−3.3 (3)
C3—C2—C7—C6	1.1 (3)	S1—C12—C17—C16	−179.44 (15)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C13—H13···O2ⁱ	0.95	2.50	3.233 (2)	134

Symmetry code: (i) −x+2, −y+1, −z+1.

Experimental details

Crystal data
Chemical formula	C₁₇H₁₅BrO₂S
M_r	363.26
Crystal system, space group	Triclinic, P1
Temperature (K)	173
a, b, c (Å)	6.1034 (1), 10.2278 (2), 12.6731 (2)
α, β, γ (°)	84.586 (1), 79.419 (1), 85.730 (1)
V (Å³)	772.87 (2)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	2.80
Crystal size (mm)	0.37 × 0.34 × 0.25

Data collection
Diffractometer	Bruker SMART APEXII CCD diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2009)
T_min, T_max	0.474, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections	14146, 3826, 3319
R_int	0.036
(sin θ/λ)_max (Å⁻¹)	0.667

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.032, 0.086, 1.06
No. of reflections	3826
No. of parameters	193
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.46, −0.83

Computer programs: APEX2 (Bruker, 2009), SAINT (Bruker, 2009), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 1998).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C13—H13···O2ⁱ	0.95	2.50	3.233 (2)	134.1

Symmetry code: (i) −x+2, −y+1, −z+1.

Acknowledgements

This work was supported by the Blue-Bio Industry Regional Innovation Center (RIC08-06-07) at Dongeui University as an RIC program under the Ministry of Knowledge Economy and Busan City.

References

Brandenburg, K. (1998). DIAMOND. Crystal Impact GbR, Bonn, Germany. Google Scholar
Bruker (2009). APEX2. SADABS and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Choi, H. D., Seo, P. J., Son, B. W. & Lee, U. (2010a). Acta Cryst. E66, o472. Web of Science CSD CrossRef IUCr Journals Google Scholar
Choi, H. D., Seo, P. J., Son, B. W. & Lee, U. (2010b). Acta Cryst. E66, o2325. Web of Science CSD CrossRef IUCr Journals Google Scholar
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565. CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar