2,5-Dimethyl-3-phenyl­sulfonyl-1-benzofuran

Choi, H.D.; Seo, P.J.; Son, B.W.; Lee, U.

doi:10.1107/S1600536808009811

organic compounds

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ISSN: 2056-9890

Volume 64| Part 5| May 2008| Page o850

doi:10.1107/S1600536808009811

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2,5-Dimethyl-3-phenylsulfonyl-1-benzofuran

Hong Dae Choi,^a Pil Ja Seo,^a Byeng Wha Son ^b 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 8 April 2008; accepted 10 April 2008; online 16 April 2008)

The title compound, C₁₆H₁₄O₃S, was prepared by the oxidation of 2,5-dimethyl-3-phenylsulfanyl-1-benzofuran with 3-chloroperoxybenzoic acid. The phenyl ring makes a dihedral angle of 76.98 (9)° with the plane of the benzofuran fragment. The crystal structure is stabilized by π–π interactions between furan and benzene rings of neighbouring molecules [centroid–centroid distance = 3.775 (4) Å]. In addition, the crystal structure exhibits intra- and intermolecular C—H⋯O interactions.

Related literature

For the crystal structures of similar 3-phenylsulfonyl-1-benzofuran derivatives, see: Choi et al. (2008a ,b ).

Experimental

Crystal data

C₁₆H₁₄O₃S
M_r = 286.33
Triclinic, $[P \overline 1]$
a = 7.476 (4) Å
b = 9.448 (5) Å
c = 11.283 (6) Å
α = 110.834 (8)°
β = 95.651 (9)°
γ = 106.122 (9)°
V = 698.0 (6) Å³
Z = 2
Mo Kα radiation
μ = 0.24 mm⁻¹
T = 298 (2) K
0.40 × 0.40 × 0.20 mm

Data collection

Bruker SMART CCD diffractometer
Absorption correction: none
4916 measured reflections
2560 independent reflections
1967 reflections with I > 2σ(I)
R_int = 0.077

Refinement

R[F² > 2σ(F²)] = 0.057
wR(F²) = 0.165
S = 1.08
2560 reflections
181 parameters
H-atom parameters constrained
Δρ_max = 0.33 e Å⁻³
Δρ_min = −0.33 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C10—H10⋯O2ⁱ	0.93	2.45	3.345 (4)	160
C14—H14⋯O3ⁱⁱ	0.93	2.50	3.263 (4)	139
C16—H16C⋯O3	0.96	2.40	3.108 (4)	130
Symmetry codes: (i) -x+1, -y, -z+1; (ii) -x+1, -y, -z.

Data collection: SMART (Bruker, 2001 ); cell refinement: SAINT (Bruker, 2001); 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/S1600536808009811/sj2482sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808009811/sj2482Isup2.hkl

checkCIF report

Comment top

As a part of our ongoing studies on the synthesis and structure of 3-phenyl-sulfonyl-1-benzofuran analogues, the crystal structure of 5-bromo-2-methyl-3-phenylsulfonyl-1-benzofuran (Choi et al., 2008a) and 2,5,7-trimethyl-3-phenylsulfonyl-1-benzofuran (Choi et al., 2008b) have been described in the literature. Herein we report the molecular and crystal structure of the title compound, 2,5-dimethyl-3-phenylsulfonyl-1-benzofuran (Fig. 1).

The benzofuran unit is essentially planar, with a mean deviation of 0.065 Å from the least-squares plane defined by the nine constituent atoms. The phenyl ring (C9—C14) makes a dihedral angle of 76.98 (9)° with the plane of the benzofuran fragment. The crystal packing (Fig. 2) is stabilized by aromatic π—π stacking interactions between the furan ring and the benzene ring from neighbouring molecules. The Cg1···Cg2ⁱⁱⁱ distance is 3.775 (4) Å (Cg1 and Cg2 are the centroids of the O1/C8/C1/C2/C7 furan and the C2—C7 benzene rings, respectively, symmetry code as in Fig. 2). The molecular packing (Fig. 2) is further stabilized by intra- and intermolecular C—H···O interactions (Table 1 and Fig. 2; symmetry codes as in Fig. 2).

Related literature top

For the crystal structures of similar 3-phenylsulfonyl-1-benzofuran derivatives, see: Choi et al. (2008a,b).

Experimental top

3-Chloroperoxybenzoic acid (77%, 717 mg, 3.2 mmol) was added in small portions to a stirred solution of 2,5-dimethyl 3-phenylsulfanyl-1-benzofuran (381 mg, 1.5 mmol) in dichloromethane (30 ml) at 273 K. After being stirred for 4 h at room temperature, the mixture was washed with saturated sodium bicarbonate solution and the organic layer was separated, dried over magnesium sulfate, filtered and concentrated in vacuum. The residue was purified by column chromatography (hexane-ethyl acetate, 2: 1 v/v) to afford the title compound as a colorless solid [yield 83%, m.p. 411–412 K; R_f = 0.67 (hexane-ethyl acetate, 2: 1 v/v)]. Single crystals suitable for X-ray diffraction were prepared by evaporation of a solution of the title compound in benzene at room temperature. Spectroscopic analysis: 1H NMR (CDCl₃, 400 MHz) δ 2.45 (s, 3H), 2.79 (s, 3H), 7.10 (d, J = 8.44 Hz, 1H), 7.29 (d, J = 8.44 Hz, 1H), 7.47–7.60 (m, 3H), 7.67 (s, 1H), 7.97–8.03 (m, 2H); EI—MS 286 [M⁺].

Computing details top

Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT (Bruker, 2001); 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, showing displacement ellipsoids drawn at the 30% probability level.
	Fig. 2. π—π and C—H···O interactions (dotted lines) in the title compound. Cg denotes the ring centroids. [Symmetry code: (i)-x + 1, -y, -z + 1: (ii) -x + 1, -y, -z, (iii) -x + 1, -y + 1, -z + 1.]

2,5-Dimethyl-3-phenylsulfonyl-1-benzofuran top

Crystal data top

C₁₆H₁₄O₃S	Z = 2
M_r = 286.33	F(000) = 300
Triclinic, P1	D_x = 1.362 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.476 (4) Å	Cell parameters from 2576 reflections
b = 9.448 (5) Å	θ = 2.5–28.2°
c = 11.283 (6) Å	µ = 0.24 mm⁻¹
α = 110.834 (8)°	T = 298 K
β = 95.651 (9)°	Block, colorless
γ = 106.122 (9)°	0.40 × 0.40 × 0.20 mm
V = 698.0 (6) Å³

Data collection top

Bruker SMART CCD diffractometer	1967 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.077
Graphite monochromator	θ_max = 25.5°, θ_min = 2.0°
Detector resolution: 10.0 pixels mm^-1	h = −9→9
ϕ and ω scans	k = −11→11
4916 measured reflections	l = −13→13
2560 independent 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)] = 0.057	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.165	H-atom parameters constrained
S = 1.08	w = 1/[σ²(F_o²) + (0.0708P)² + 0.3092P] where P = (F_o² + 2F_c²)/3
2560 reflections	(Δ/σ)_max < 0.001
181 parameters	Δρ_max = 0.33 e Å⁻³
0 restraints	Δρ_min = −0.33 e Å⁻³

Crystal data top

C₁₆H₁₄O₃S	γ = 106.122 (9)°
M_r = 286.33	V = 698.0 (6) Å³
Triclinic, P1	Z = 2
a = 7.476 (4) Å	Mo Kα radiation
b = 9.448 (5) Å	µ = 0.24 mm⁻¹
c = 11.283 (6) Å	T = 298 K
α = 110.834 (8)°	0.40 × 0.40 × 0.20 mm
β = 95.651 (9)°

Data collection top

Bruker SMART CCD diffractometer	1967 reflections with I > 2σ(I)
4916 measured reflections	R_int = 0.077
2560 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.057	0 restraints
wR(F²) = 0.165	H-atom parameters constrained
S = 1.08	Δρ_max = 0.33 e Å⁻³
2560 reflections	Δρ_min = −0.33 e Å⁻³
181 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
S	0.48253 (10)	0.09684 (9)	0.28377 (7)	0.0479 (3)
O1	0.7729 (3)	0.5526 (2)	0.3996 (2)	0.0621 (6)
O2	0.3828 (3)	0.0486 (3)	0.37248 (19)	0.0587 (6)
O3	0.3765 (3)	0.0689 (3)	0.1608 (2)	0.0660 (6)
C1	0.6127 (4)	0.2991 (3)	0.3636 (3)	0.0469 (7)
C2	0.6846 (4)	0.3858 (3)	0.5024 (3)	0.0457 (7)
C3	0.6797 (4)	0.3508 (3)	0.6115 (3)	0.0492 (7)
H3	0.6177	0.2466	0.6032	0.059*
C4	0.7678 (5)	0.4719 (4)	0.7328 (3)	0.0585 (8)
C5	0.8626 (5)	0.6271 (4)	0.7433 (4)	0.0672 (9)
H5	0.9217	0.7078	0.8254	0.081*
C6	0.8716 (5)	0.6647 (4)	0.6369 (4)	0.0679 (10)
H6	0.9349	0.7686	0.6452	0.082*
C7	0.7827 (4)	0.5416 (3)	0.5174 (3)	0.0523 (8)
C8	0.6696 (4)	0.4052 (4)	0.3078 (3)	0.0551 (8)
C9	0.6558 (4)	0.0025 (3)	0.2563 (3)	0.0453 (7)
C10	0.7288 (5)	−0.0414 (4)	0.3494 (3)	0.0573 (8)
H10	0.6869	−0.0227	0.4266	0.069*
C11	0.8658 (6)	−0.1138 (4)	0.3250 (5)	0.0807 (12)
H11	0.9164	−0.1452	0.3862	0.097*
C12	0.9277 (6)	−0.1397 (4)	0.2115 (5)	0.0897 (14)
H12	1.0212	−0.1875	0.1965	0.108*
C13	0.8531 (6)	−0.0959 (5)	0.1201 (4)	0.0846 (13)
H13	0.8956	−0.1144	0.0430	0.102*
C14	0.7170 (5)	−0.0252 (4)	0.1413 (3)	0.0609 (9)
H14	0.6658	0.0042	0.0789	0.073*
C15	0.7617 (6)	0.4376 (5)	0.8531 (3)	0.0803 (11)
H15A	0.8192	0.3571	0.8480	0.096*
H15B	0.6315	0.3995	0.8596	0.096*
H15C	0.8307	0.5343	0.9283	0.096*
C16	0.6474 (6)	0.3918 (5)	0.1724 (4)	0.0784 (11)
H16A	0.7708	0.4175	0.1517	0.094*
H16B	0.5864	0.4652	0.1627	0.094*
H16C	0.5708	0.2839	0.1146	0.094*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
S	0.0448 (4)	0.0527 (4)	0.0352 (4)	0.0039 (3)	0.0014 (3)	0.0167 (3)
O1	0.0632 (13)	0.0498 (12)	0.0805 (17)	0.0183 (10)	0.0197 (12)	0.0338 (12)
O2	0.0548 (12)	0.0617 (13)	0.0447 (13)	0.0014 (10)	0.0117 (10)	0.0183 (10)
O3	0.0587 (12)	0.0829 (16)	0.0470 (14)	0.0146 (12)	−0.0054 (11)	0.0268 (12)
C1	0.0428 (14)	0.0491 (16)	0.0488 (18)	0.0137 (12)	0.0075 (13)	0.0217 (14)
C2	0.0395 (13)	0.0424 (15)	0.0505 (18)	0.0135 (11)	0.0072 (13)	0.0141 (13)
C3	0.0510 (15)	0.0442 (15)	0.0435 (18)	0.0126 (13)	0.0034 (14)	0.0118 (13)
C4	0.0577 (17)	0.0580 (19)	0.050 (2)	0.0242 (15)	0.0027 (15)	0.0097 (15)
C5	0.0649 (19)	0.0506 (18)	0.060 (2)	0.0172 (16)	−0.0003 (17)	−0.0023 (16)
C6	0.0588 (19)	0.0379 (16)	0.089 (3)	0.0111 (14)	0.0075 (19)	0.0111 (17)
C7	0.0473 (15)	0.0450 (16)	0.066 (2)	0.0183 (13)	0.0126 (15)	0.0221 (15)
C8	0.0525 (17)	0.0607 (19)	0.061 (2)	0.0214 (15)	0.0129 (15)	0.0324 (17)
C9	0.0481 (14)	0.0387 (13)	0.0333 (15)	0.0015 (11)	−0.0006 (12)	0.0089 (11)
C10	0.0599 (18)	0.0500 (17)	0.0522 (19)	0.0051 (15)	−0.0004 (15)	0.0228 (15)
C11	0.075 (2)	0.052 (2)	0.103 (3)	0.0119 (18)	−0.013 (2)	0.032 (2)
C12	0.074 (2)	0.051 (2)	0.121 (4)	0.0243 (19)	0.013 (3)	0.007 (2)
C13	0.092 (3)	0.064 (2)	0.076 (3)	0.023 (2)	0.030 (2)	0.002 (2)
C14	0.072 (2)	0.0576 (19)	0.0381 (17)	0.0135 (16)	0.0081 (16)	0.0098 (14)
C15	0.098 (3)	0.080 (3)	0.047 (2)	0.034 (2)	−0.003 (2)	0.0103 (18)
C16	0.087 (3)	0.089 (3)	0.078 (3)	0.028 (2)	0.020 (2)	0.056 (2)

Geometric parameters (Å, º) top

S—O3	1.425 (2)	C8—C16	1.476 (4)
S—O2	1.431 (2)	C9—C10	1.376 (4)
S—C1	1.726 (3)	C9—C14	1.380 (4)
S—C9	1.758 (3)	C10—C11	1.380 (5)
O1—C8	1.353 (4)	C10—H10	0.9300
O1—C7	1.366 (4)	C11—C12	1.367 (6)
C1—C8	1.359 (4)	C11—H11	0.9300
C1—C2	1.446 (4)	C12—C13	1.366 (6)
C2—C3	1.385 (4)	C12—H12	0.9300
C2—C7	1.389 (4)	C13—C14	1.360 (6)
C3—C4	1.381 (4)	C13—H13	0.9300
C3—H3	0.9300	C14—H14	0.9300
C4—C5	1.396 (5)	C15—H15A	0.9600
C4—C15	1.505 (5)	C15—H15B	0.9600
C5—C6	1.370 (5)	C15—H15C	0.9600
C5—H5	0.9300	C16—H16A	0.9600
C6—C7	1.375 (5)	C16—H16B	0.9600
C6—H6	0.9300	C16—H16C	0.9600

O3—S—O2	118.96 (14)	C10—C9—C14	121.2 (3)
O3—S—C1	109.04 (14)	C10—C9—S	119.9 (2)
O2—S—C1	107.44 (13)	C14—C9—S	119.0 (3)
O3—S—C9	108.12 (14)	C9—C10—C11	118.3 (3)
O2—S—C9	107.90 (14)	C9—C10—H10	120.9
C1—S—C9	104.45 (14)	C11—C10—H10	120.9
C8—O1—C7	107.4 (2)	C12—C11—C10	120.5 (4)
C8—C1—C2	107.5 (3)	C12—C11—H11	119.8
C8—C1—S	126.5 (3)	C10—C11—H11	119.8
C2—C1—S	126.0 (2)	C13—C12—C11	120.4 (4)
C3—C2—C7	119.1 (3)	C13—C12—H12	119.8
C3—C2—C1	136.9 (3)	C11—C12—H12	119.8
C7—C2—C1	104.0 (3)	C14—C13—C12	120.3 (4)
C4—C3—C2	119.4 (3)	C14—C13—H13	119.8
C4—C3—H3	120.3	C12—C13—H13	119.8
C2—C3—H3	120.3	C13—C14—C9	119.4 (4)
C3—C4—C5	119.4 (3)	C13—C14—H14	120.3
C3—C4—C15	120.5 (3)	C9—C14—H14	120.3
C5—C4—C15	120.1 (3)	C4—C15—H15A	109.5
C6—C5—C4	122.4 (3)	C4—C15—H15B	109.5
C6—C5—H5	118.8	H15A—C15—H15B	109.5
C4—C5—H5	118.8	C4—C15—H15C	109.5
C5—C6—C7	116.9 (3)	H15A—C15—H15C	109.5
C5—C6—H6	121.6	H15B—C15—H15C	109.5
C7—C6—H6	121.6	C8—C16—H16A	109.5
O1—C7—C6	126.5 (3)	C8—C16—H16B	109.5
O1—C7—C2	110.7 (3)	H16A—C16—H16B	109.5
C6—C7—C2	122.8 (3)	C8—C16—H16C	109.5
O1—C8—C1	110.4 (3)	H16A—C16—H16C	109.5
O1—C8—C16	115.5 (3)	H16B—C16—H16C	109.5
C1—C8—C16	134.1 (3)

O3—S—C1—C8	−24.0 (3)	C3—C2—C7—C6	−1.8 (5)
O2—S—C1—C8	−154.2 (3)	C1—C2—C7—C6	178.9 (3)
C9—S—C1—C8	91.3 (3)	C7—O1—C8—C1	0.0 (3)
O3—S—C1—C2	157.4 (2)	C7—O1—C8—C16	−178.4 (3)
O2—S—C1—C2	27.2 (3)	C2—C1—C8—O1	0.3 (4)
C9—S—C1—C2	−87.2 (3)	S—C1—C8—O1	−178.5 (2)
C8—C1—C2—C3	−179.4 (3)	C2—C1—C8—C16	178.2 (4)
S—C1—C2—C3	−0.6 (5)	S—C1—C8—C16	−0.6 (6)
C8—C1—C2—C7	−0.4 (3)	O3—S—C9—C10	−156.0 (2)
S—C1—C2—C7	178.4 (2)	O2—S—C9—C10	−26.2 (2)
C7—C2—C3—C4	1.7 (4)	C1—S—C9—C10	87.9 (2)
C1—C2—C3—C4	−179.4 (3)	O3—S—C9—C14	24.4 (3)
C2—C3—C4—C5	−0.9 (5)	O2—S—C9—C14	154.3 (2)
C2—C3—C4—C15	179.0 (3)	C1—S—C9—C14	−91.6 (2)
C3—C4—C5—C6	0.2 (6)	C14—C9—C10—C11	0.2 (4)
C15—C4—C5—C6	−179.8 (3)	S—C9—C10—C11	−179.4 (2)
C4—C5—C6—C7	−0.2 (5)	C9—C10—C11—C12	0.5 (5)
C8—O1—C7—C6	−178.7 (3)	C10—C11—C12—C13	−0.8 (6)
C8—O1—C7—C2	−0.2 (3)	C11—C12—C13—C14	0.3 (6)
C5—C6—C7—O1	179.4 (3)	C12—C13—C14—C9	0.3 (5)
C5—C6—C7—C2	1.1 (5)	C10—C9—C14—C13	−0.6 (4)
C3—C2—C7—O1	179.6 (2)	S—C9—C14—C13	179.0 (2)
C1—C2—C7—O1	0.4 (3)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C10—H10···O2ⁱ	0.93	2.45	3.345 (4)	160
C14—H14···O3ⁱⁱ	0.93	2.50	3.263 (4)	139
C16—H16C···O3	0.96	2.40	3.108 (4)	130

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

Experimental details

Crystal data
Chemical formula	C₁₆H₁₄O₃S
M_r	286.33
Crystal system, space group	Triclinic, P1
Temperature (K)	298
a, b, c (Å)	7.476 (4), 9.448 (5), 11.283 (6)
α, β, γ (°)	110.834 (8), 95.651 (9), 106.122 (9)
V (Å³)	698.0 (6)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.24
Crystal size (mm)	0.40 × 0.40 × 0.20

Data collection
Diffractometer	Bruker SMART CCD diffractometer
Absorption correction	–
No. of measured, independent and observed [I > 2σ(I)] reflections	4916, 2560, 1967
R_int	0.077
(sin θ/λ)_max (Å⁻¹)	0.606

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.057, 0.165, 1.08
No. of reflections	2560
No. of parameters	181
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.33, −0.33

Computer programs: SMART (Bruker, 2001), SAINT (Bruker, 2001), 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
C10—H10···O2ⁱ	0.93	2.45	3.345 (4)	160.3
C14—H14···O3ⁱⁱ	0.93	2.50	3.263 (4)	138.9
C16—H16C···O3	0.96	2.40	3.108 (4)	130.0

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

References

Brandenburg, K. (1998). DIAMOND. Crystal Impact GbR, Bonn, Germany. Google Scholar
Bruker (2001). SAINT and SMART. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Choi, H. D., Seo, P. J., Son, B. W. & Lee, U. (2008a). Acta Cryst. E64, o793. Web of Science CSD CrossRef IUCr Journals Google Scholar
Choi, H. D., Seo, P. J., Son, B. W. & Lee, U. (2008b). Acta Cryst. E64, o794. 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

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Volume 64| Part 5| May 2008| Page o850

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