Isopropyl 2-(5-chloro-3-methyl­sulfinyl-1-benzofuran-2-yl)acetate

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

doi:10.1107/S1600536808039937

organic compounds

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ISSN: 2056-9890

Volume 65| Part 1| January 2009| Page o3

doi:10.1107/S1600536808039937

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Isopropyl 2-(5-chloro-3-methylsulfinyl-1-benzofuran-2-yl)acetate

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 27 November 2008; accepted 27 November 2008; online 3 December 2008)

In the title compound, C₁₄H₁₅ClO₄S, the S atom has a distorted trigonal-pyramidal coordination. The O atom and the methyl group of the methylsulfinyl substituent lie on opposite sides of the benzofuran ring system. The crystal structure is stabilized by intermolecular aromatic π–π interactions between the benzene rings of neighbouring molecules [centroid–centroid distance = 4.057 (3) Å], and by C—H⋯π interactions between a methyl H atom and the benzene ring of an adjacent molecule.

Related literature

For the crystal structures of similar compounds, see: Choi et al. (2008a ,b ).

Experimental

Crystal data

C₁₄H₁₅ClO₄S
M_r = 314.77
Triclinic, $[P \overline 1]$
a = 7.8824 (6) Å
b = 10.0352 (8) Å
c = 10.9004 (8) Å
α = 69.254 (1)°
β = 81.662 (1)°
γ = 67.703 (1)°
V = 745.98 (10) Å³
Z = 2
Mo Kα radiation
μ = 0.41 mm⁻¹
T = 298 (2) K
0.50 × 0.40 × 0.15 mm

Data collection

Bruker SMART CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1999 ) T_min = 0.816, T_max = 0.939
5508 measured reflections
2602 independent reflections
2354 reflections with I > 2σ(I)
R_int = 0.017

Refinement

R[F² > 2σ(F²)] = 0.048
wR(F²) = 0.124
S = 1.12
2602 reflections
184 parameters
H-atom parameters constrained
Δρ_max = 0.49 e Å⁻³
Δρ_min = −0.29 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C13—H13B⋯Cgⁱ	0.96	2.78	3.515 (3)	134
Symmetry code: (i) x, y+1, z. Cg is the centroid of the C2–C7 benzene ring.

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/S1600536808039937/ng2521sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808039937/ng2521Isup2.hkl

checkCIF report

Comment top

As a part of our ongoing research on the synthesis and structure of isopropyl 2-(5-halo-3-methylsulfinyl-1-benzofuran-2-yl)acetate analogues, we have recently described the crystal structures of isopropyl 2-(5-bromo-3-methylsulfinyl-1-benzofuran-2-yl)acetate (Choi et al., 2008a) and isopropyl 2-(5-iodo-3-methylsulfinyl-1-benzofuran-2-yl)acetate (Choi et al., 2008b). Here we report the crystal structure of the title compound, isopropyl 2-(5-chloro-3-methylsulfinyl-1-benzofuran-2-yl)acetate (Fig. 1).

The benzofuran unit is essentially planar, with a mean deviation of 0.012 (2) Å from the least-squares plane defined by the nine constituent atoms. The molecular packing is stabilized by aromatic π—π stacking interactions between the benzene rings of adjacent molecules. The Cg···Cgⁱⁱ distance is 4.057 (3) Å (Fig. 2; Cg is the centroid of C2—C7 benzene ring; symmetry code as in Fig. 2). The molecular packing is further stabilized by C—H···π interactions between a methyl H atom of isoproyl group and the benzene ring of the benzofuran uint, with a C13—H13B···Cgⁱ separation of 2.78 Å (Fig. 2 and Table 1; Cg is the centroid of the C2-C7 benzene ring).

Related literature top

For the crystal structures of similar compounds, see: Choi et al. (2008a,b).

Experimental top

77% 3-chloroperoxybenzoic acid (173 mg, 0.77 mmol) was added in small portions to a stirred solution of isopropyl 2-(5-chloro-3-methylsulfanyl-1-benzofuran-2-yl)acetate (209 mg, 0.7 mmol) in dichloromethane (30 ml) at 273 K. After being stirred for 3 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, 1:2 v/v) to afford the title compound as a colorless solid [yield 83%, m.p. 422–423 K; R_f = 0.52 (hexane-ethyl acetate, 1;2 v/v)]. Single crystals suitable for X-ray diffraction were prepared by evaporation of a solution of the title compound in acetone at room temperature. Spectroscopic analysis: ¹H NMR (CDCl₃, 400 MHz) δ 1.28 (d, J = 6.20 Hz, 6H), 3.08 (s, 3H), 4.0 (s, 2H), 5.02-5.08 (m, 1H), 7.35 (dd, J = 8.76 Hz and J = 1.84 Hz, 1H), 7.45 (d, J = 8.76 Hz, 1H), 7.95 (d, J = 1.84 Hz, 1H); EI-MS 316 [M+2], 314 [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···π interactions (dotted lines) in the title compound. Cg denotes ring centroid.[Symmetry code: (i) x, y+1, z; (ii) -x+1, -y+1, -z+2; (iii) x, y-1, z.]

Isopropyl 2-(5-chloro-3-methylsulfinyl-1-benzofuran-2-yl)acetate top

Crystal data top

C₁₄H₁₅ClO₄S	Z = 2
M_r = 314.77	F(000) = 328
Triclinic, P1	D_x = 1.401 Mg m⁻³
Hall symbol: -P 1	Melting point = 422–423 K
a = 7.8824 (6) Å	Mo Kα radiation, λ = 0.71073 Å
b = 10.0352 (8) Å	Cell parameters from 4167 reflections
c = 10.9004 (8) Å	θ = 2.5–28.3°
α = 69.254 (1)°	µ = 0.41 mm⁻¹
β = 81.662 (1)°	T = 298 K
γ = 67.703 (1)°	Plate, colorless
V = 745.98 (10) Å³	0.50 × 0.40 × 0.15 mm

Data collection top

Bruker SMART CCD diffractometer	2602 independent reflections
Radiation source: fine-focus sealed tube	2354 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.017
Detector resolution: 10.0 pixels mm^-1	θ_max = 25.0°, θ_min = 2.5°
ϕ and ω scans	h = −9→9
Absorption correction: multi-scan (SADABS; Sheldrick, 1999)	k = −11→11
T_min = 0.816, T_max = 0.939	l = −12→12
5508 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)] = 0.048	Hydrogen site location: difference Fourier map
wR(F²) = 0.125	H-atom parameters constrained
S = 1.12	w = 1/[σ²(F_o²) + (0.0534P)² + 0.4971P] where P = (F_o² + 2F_c²)/3
2602 reflections	(Δ/σ)_max < 0.001
184 parameters	Δρ_max = 0.49 e Å⁻³
0 restraints	Δρ_min = −0.29 e Å⁻³

Crystal data top

C₁₄H₁₅ClO₄S	γ = 67.703 (1)°
M_r = 314.77	V = 745.98 (10) Å³
Triclinic, P1	Z = 2
a = 7.8824 (6) Å	Mo Kα radiation
b = 10.0352 (8) Å	µ = 0.41 mm⁻¹
c = 10.9004 (8) Å	T = 298 K
α = 69.254 (1)°	0.50 × 0.40 × 0.15 mm
β = 81.662 (1)°

Data collection top

Bruker SMART CCD diffractometer	2602 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1999)	2354 reflections with I > 2σ(I)
T_min = 0.816, T_max = 0.939	R_int = 0.017
5508 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.048	0 restraints
wR(F²) = 0.125	H-atom parameters constrained
S = 1.12	Δρ_max = 0.49 e Å⁻³
2602 reflections	Δρ_min = −0.29 e Å⁻³
184 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
S	0.74726 (9)	0.60225 (8)	0.54010 (6)	0.0480 (2)
Cl	0.29574 (12)	0.21443 (10)	0.87346 (10)	0.0816 (3)
O1	0.8348 (2)	0.45903 (19)	0.91914 (16)	0.0435 (4)
O2	0.7488 (3)	0.4832 (3)	0.48756 (19)	0.0637 (6)
O3	1.0254 (3)	0.8446 (2)	0.7284 (2)	0.0582 (5)
O4	0.7414 (3)	0.8557 (2)	0.7070 (2)	0.0674 (6)
C1	0.7475 (3)	0.5246 (3)	0.7125 (2)	0.0393 (5)
C2	0.6447 (3)	0.4337 (3)	0.7973 (2)	0.0378 (5)
C3	0.5137 (3)	0.3799 (3)	0.7797 (3)	0.0462 (6)
H3	0.4686	0.4043	0.6972	0.055*
C4	0.4550 (4)	0.2888 (3)	0.8910 (3)	0.0510 (7)
C5	0.5171 (4)	0.2520 (3)	1.0159 (3)	0.0544 (7)
H5	0.4720	0.1905	1.0878	0.065*
C6	0.6450 (4)	0.3061 (3)	1.0341 (3)	0.0486 (6)
H6	0.6878	0.2832	1.1170	0.058*
C7	0.7062 (3)	0.3959 (3)	0.9229 (2)	0.0408 (5)
C8	0.8579 (3)	0.5352 (3)	0.7894 (2)	0.0409 (5)
C9	0.9910 (3)	0.6147 (3)	0.7601 (3)	0.0455 (6)
H9A	1.0667	0.5947	0.6856	0.055*
H9B	1.0708	0.5735	0.8347	0.055*
C10	0.9005 (4)	0.7845 (3)	0.7302 (2)	0.0437 (6)
C11	0.9615 (5)	1.0095 (3)	0.7059 (4)	0.0697 (9)
H11	0.8528	1.0642	0.6503	0.084*
C12	1.1212 (8)	1.0569 (5)	0.6388 (5)	0.1199 (18)
H12A	1.0856	1.1656	0.6142	0.180*
H12B	1.1570	1.0267	0.5619	0.180*
H12C	1.2226	1.0085	0.6979	0.180*
C13	0.9213 (8)	1.0315 (4)	0.8347 (5)	0.1195 (19)
H13A	0.8255	0.9938	0.8777	0.179*
H13B	0.8825	1.1381	0.8233	0.179*
H13C	1.0296	0.9770	0.8872	0.179*
C14	0.5183 (4)	0.7385 (4)	0.5211 (3)	0.0671 (8)
H14A	0.4977	0.7998	0.4304	0.101*
H14B	0.5018	0.8027	0.5728	0.101*
H14C	0.4327	0.6861	0.5499	0.101*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
S	0.0489 (4)	0.0589 (4)	0.0385 (4)	−0.0261 (3)	−0.0038 (3)	−0.0100 (3)
Cl	0.0694 (5)	0.0748 (6)	0.1092 (7)	−0.0480 (5)	−0.0073 (5)	−0.0132 (5)
O1	0.0486 (10)	0.0464 (9)	0.0398 (9)	−0.0184 (8)	−0.0057 (7)	−0.0154 (7)
O2	0.0685 (13)	0.0804 (14)	0.0515 (12)	−0.0250 (11)	−0.0047 (9)	−0.0322 (11)
O3	0.0622 (12)	0.0429 (10)	0.0740 (13)	−0.0240 (9)	−0.0176 (10)	−0.0120 (9)
O4	0.0501 (12)	0.0510 (11)	0.0946 (16)	−0.0161 (10)	−0.0120 (11)	−0.0139 (11)
C1	0.0427 (13)	0.0388 (12)	0.0383 (13)	−0.0157 (10)	−0.0035 (10)	−0.0124 (10)
C2	0.0390 (12)	0.0345 (12)	0.0401 (13)	−0.0113 (10)	−0.0023 (10)	−0.0134 (10)
C3	0.0438 (14)	0.0438 (14)	0.0532 (15)	−0.0174 (11)	−0.0051 (11)	−0.0146 (12)
C4	0.0428 (14)	0.0421 (14)	0.0682 (18)	−0.0179 (11)	−0.0002 (12)	−0.0153 (13)
C5	0.0541 (16)	0.0437 (14)	0.0553 (16)	−0.0172 (13)	0.0089 (13)	−0.0084 (12)
C6	0.0509 (15)	0.0428 (14)	0.0432 (14)	−0.0102 (12)	0.0007 (11)	−0.0111 (11)
C7	0.0404 (13)	0.0353 (12)	0.0457 (13)	−0.0099 (10)	−0.0016 (10)	−0.0155 (10)
C8	0.0430 (13)	0.0374 (12)	0.0434 (13)	−0.0130 (10)	−0.0041 (10)	−0.0145 (10)
C9	0.0443 (14)	0.0476 (14)	0.0509 (15)	−0.0201 (11)	−0.0050 (11)	−0.0176 (12)
C10	0.0484 (15)	0.0482 (14)	0.0384 (13)	−0.0223 (12)	−0.0030 (11)	−0.0121 (11)
C11	0.082 (2)	0.0406 (15)	0.085 (2)	−0.0242 (15)	−0.0304 (18)	−0.0055 (15)
C12	0.181 (5)	0.083 (3)	0.115 (4)	−0.086 (3)	0.035 (3)	−0.027 (3)
C13	0.159 (5)	0.056 (2)	0.121 (4)	−0.018 (3)	0.045 (3)	−0.042 (2)
C14	0.0657 (19)	0.0586 (18)	0.0640 (19)	−0.0112 (15)	−0.0194 (15)	−0.0095 (15)

Geometric parameters (Å, º) top

S—O2	1.493 (2)	C6—C7	1.378 (4)
S—C1	1.761 (2)	C6—H6	0.9300
S—C14	1.790 (3)	C8—C9	1.482 (3)
Cl—C4	1.747 (3)	C9—C10	1.506 (4)
O1—C8	1.372 (3)	C9—H9A	0.9700
O1—C7	1.374 (3)	C9—H9B	0.9700
O3—C10	1.331 (3)	C11—C13	1.469 (6)
O3—C11	1.472 (3)	C11—C12	1.513 (6)
O4—C10	1.196 (3)	C11—H11	0.9800
C1—C8	1.348 (3)	C12—H12A	0.9600
C1—C2	1.445 (3)	C12—H12B	0.9600
C2—C7	1.392 (3)	C12—H12C	0.9600
C2—C3	1.396 (3)	C13—H13A	0.9600
C3—C4	1.376 (4)	C13—H13B	0.9600
C3—H3	0.9300	C13—H13C	0.9600
C4—C5	1.390 (4)	C14—H14A	0.9600
C5—C6	1.378 (4)	C14—H14B	0.9600
C5—H5	0.9300	C14—H14C	0.9600

O2—S—C1	107.34 (12)	C10—C9—H9A	109.0
O2—S—C14	106.36 (14)	C8—C9—H9B	109.0
C1—S—C14	98.16 (14)	C10—C9—H9B	109.0
C8—O1—C7	106.25 (18)	H9A—C9—H9B	107.8
C10—O3—C11	117.8 (2)	O4—C10—O3	124.9 (2)
C8—C1—C2	107.3 (2)	O4—C10—C9	125.3 (2)
C8—C1—S	123.59 (19)	O3—C10—C9	109.8 (2)
C2—C1—S	129.04 (18)	C13—C11—O3	107.5 (3)
C7—C2—C3	119.7 (2)	C13—C11—C12	111.2 (4)
C7—C2—C1	104.6 (2)	O3—C11—C12	104.8 (3)
C3—C2—C1	135.7 (2)	C13—C11—H11	111.0
C4—C3—C2	116.3 (2)	O3—C11—H11	111.0
C4—C3—H3	121.8	C12—C11—H11	111.0
C2—C3—H3	121.8	C11—C12—H12A	109.5
C3—C4—C5	123.4 (2)	C11—C12—H12B	109.5
C3—C4—Cl	118.1 (2)	H12A—C12—H12B	109.5
C5—C4—Cl	118.5 (2)	C11—C12—H12C	109.5
C6—C5—C4	120.5 (2)	H12A—C12—H12C	109.5
C6—C5—H5	119.8	H12B—C12—H12C	109.5
C4—C5—H5	119.8	C11—C13—H13A	109.5
C5—C6—C7	116.4 (2)	C11—C13—H13B	109.5
C5—C6—H6	121.8	H13A—C13—H13B	109.5
C7—C6—H6	121.8	C11—C13—H13C	109.5
O1—C7—C6	125.7 (2)	H13A—C13—H13C	109.5
O1—C7—C2	110.7 (2)	H13B—C13—H13C	109.5
C6—C7—C2	123.6 (2)	S—C14—H14A	109.5
C1—C8—O1	111.2 (2)	S—C14—H14B	109.5
C1—C8—C9	132.5 (2)	H14A—C14—H14B	109.5
O1—C8—C9	116.3 (2)	S—C14—H14C	109.5
C8—C9—C10	113.1 (2)	H14A—C14—H14C	109.5
C8—C9—H9A	109.0	H14B—C14—H14C	109.5

O2—S—C1—C8	133.8 (2)	C3—C2—C7—O1	179.7 (2)
C14—S—C1—C8	−116.2 (2)	C1—C2—C7—O1	0.9 (3)
O2—S—C1—C2	−42.4 (3)	C3—C2—C7—C6	0.1 (4)
C14—S—C1—C2	67.7 (3)	C1—C2—C7—C6	−178.6 (2)
C8—C1—C2—C7	−0.3 (3)	C2—C1—C8—O1	−0.5 (3)
S—C1—C2—C7	176.39 (19)	S—C1—C8—O1	−177.37 (16)
C8—C1—C2—C3	−178.7 (3)	C2—C1—C8—C9	−178.7 (2)
S—C1—C2—C3	−2.1 (4)	S—C1—C8—C9	4.4 (4)
C7—C2—C3—C4	−0.9 (4)	C7—O1—C8—C1	1.1 (3)
C1—C2—C3—C4	177.4 (3)	C7—O1—C8—C9	179.6 (2)
C2—C3—C4—C5	1.1 (4)	C1—C8—C9—C10	75.3 (4)
C2—C3—C4—Cl	−178.30 (19)	O1—C8—C9—C10	−102.9 (2)
C3—C4—C5—C6	−0.5 (4)	C11—O3—C10—O4	4.8 (4)
Cl—C4—C5—C6	178.9 (2)	C11—O3—C10—C9	−177.6 (2)
C4—C5—C6—C7	−0.3 (4)	C8—C9—C10—O4	−13.6 (4)
C8—O1—C7—C6	178.3 (2)	C8—C9—C10—O3	168.8 (2)
C8—O1—C7—C2	−1.2 (3)	C10—O3—C11—C13	91.0 (4)
C5—C6—C7—O1	−179.0 (2)	C10—O3—C11—C12	−150.6 (3)
C5—C6—C7—C2	0.5 (4)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C13—H13B···Cgⁱ	0.96	2.78	3.515 (3)	134

Symmetry code: (i) x, y+1, z.

Experimental details

Crystal data
Chemical formula	C₁₄H₁₅ClO₄S
M_r	314.77
Crystal system, space group	Triclinic, P1
Temperature (K)	298
a, b, c (Å)	7.8824 (6), 10.0352 (8), 10.9004 (8)
α, β, γ (°)	69.254 (1), 81.662 (1), 67.703 (1)
V (Å³)	745.98 (10)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.41
Crystal size (mm)	0.50 × 0.40 × 0.15

Data collection
Diffractometer	Bruker SMART CCD diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1999)
T_min, T_max	0.816, 0.939
No. of measured, independent and observed [I > 2σ(I)] reflections	5508, 2602, 2354
R_int	0.017
(sin θ/λ)_max (Å⁻¹)	0.594

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.048, 0.125, 1.12
No. of reflections	2602
No. of parameters	184
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.49, −0.29

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
C13—H13B···Cgⁱ	0.96	2.78	3.515 (3)	134.4

Symmetry code: (i) x, y+1, 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, o2250. Web of Science CSD CrossRef IUCr Journals Google Scholar
Choi, H. D., Seo, P. J., Son, B. W. & Lee, U. (2008b). Acta Cryst. E64, o2384. 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. (1999). SADABS. University of Göttingen, Germany. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar

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