4-Chloro-N-(2-chloro­phen­yl)-2-methyl­benzene­sulfonamide

Gowda, B.T.; Foro, S.; Nirmala, P.G.; Babitha, K.S.; Fuess, H.

doi:10.1107/S1600536809007880

organic compounds

CRYSTALLOGRAPHIC
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ISSN: 2056-9890

Volume 65| Part 4| April 2009| Page o717

doi:10.1107/S1600536809007880

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4-Chloro-N-(2-chlorophenyl)-2-methylbenzenesulfonamide

B. Thimme Gowda,^a ^* Sabine Foro,^b P. G. Nirmala,^a K. S. Babitha ^a and Hartmut Fuess ^b

^aDepartment of Chemistry, Mangalore University, Mangalagangotri 574 199, Mangalore, India, and ^bInstitute of Materials Science, Darmstadt University of Technology, Petersenstrasse 23, D-64287 Darmstadt, Germany
^*Correspondence e-mail: gowdabt@yahoo.com

(Received 28 February 2009; accepted 4 March 2009; online 11 March 2009)

In the crystal structure of the title compound, C₁₃H₁₁Cl₂NO₂S, the conformations of the N—C bond in the C—SO₂—NH—C segment are trans and gauche with respect to the S=O bonds. The C—S(O₂)—N(H)—C torsion angle is 74.8 (4)°, indicating that the molecule is bent at the S atom. In the crystal structure, inversion dimers linked by pairs of N—H⋯O hydrogen bonds occur. An intramolecular N—H⋯Cl interaction is also present.

Related literature

For related structures of N-(aryl)-arylsulfonamides, see: Gelbrich et al. (2007 ); Gowda et al. (2009a ,b ); Perlovich et al. (2006 ).

Experimental

Crystal data

C₁₃H₁₁Cl₂NO₂S
M_r = 316.19
Triclinic, $[P \overline 1]$
a = 8.089 (2) Å
b = 8.096 (2) Å
c = 10.946 (3) Å
α = 96.00 (1)°
β = 97.11 (2)°
γ = 105.67 (2)°
V = 677.7 (3) Å³
Z = 2
Cu Kα radiation
μ = 5.73 mm⁻¹
T = 299 K
0.45 × 0.33 × 0.08 mm

Data collection

Enraf–Nonius CAD-4 diffractometer
Absorption correction: ψ scan (North et al., 1968 ) T_min = 0.150, T_max = 0.640
2684 measured reflections
2414 independent reflections
1932 reflections with I > 2σ(I)
R_int = 0.037
3 standard reflections frequency: 120 min intensity decay: 1.0%

Refinement

R[F² > 2σ(F²)] = 0.083
wR(F²) = 0.236
S = 1.05
2414 reflections
177 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.60 e Å⁻³
Δρ_min = −0.67 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1N⋯O2ⁱ	0.88 (5)	2.17 (5)	2.994 (5)	157 (4)
N1—H1N⋯Cl2	0.88 (5)	2.67 (5)	3.011 (4)	104 (4)
Symmetry code: (i) -x+1, -y, -z.

Data collection: CAD-4-PC (Enraf–Nonius, 1996 ); cell refinement: CAD-4-PC; data reduction: REDU4 (Stoe & Cie, 1987 ); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009 ); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809007880/tk2384sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809007880/tk2384Isup2.hkl

checkCIF report

Comment top

In the present work, as part of a study of substituent effects on the structures of N-(aryl)-arylsulfonamides (Gowda et al. 2008a,b, 2009), the structure of 2-methyl-4-chloro-N-(2-chlorophenyl)benzenesulfonamide (I) has been determined. The conformations of the N—C bond in the C—S(O₂)—N(H)—C segment are trans and gauche with respect to the S=O bonds (Fig. 1). The torsion angle of C1—S1—N1—C1 is 74.8 (4)°, indicating the molecule is bent at the S1 atom. The two benzene rings are tilted relative to each other by 45.5 (2)°, compared with the values of 86.6 (2)° (molecule 1) and 83.0 (2)° (molecule 2), in the two independent molecules of 2-methyl-4-chloro-N-(phenyl)-benzenesulfonamide (II) (Gowda et al., 2009). Bond distance parameters in (I) are similar to those observed in (II), 2,4-dimethyl-N-(phenyl)benzenesulfonamide (Gowda et al., 2008b) and other aryl sulfonamides (Perlovich et al., 2006; Gelbrich et al., 2007). The crystal structure comprises the packing of centrosymmetric molecules connected via N—H···O hydrogen bonds (Table 1 & Fig. 2).

Related literature top

For related structures of N-(aryl)-arylsulfonamides, see: Gelbrich et al. (2007); Gowda et al. (2009a,b); Perlovich et al. (2006).

Experimental top

m-Chlorotoluene (10 ml) in chloroform (40 ml) was treated dropwise with chlorosulfonic acid (25 ml) at 0° C. After the initial evolution of HCl subsided, the reaction mixture was brought to room temperature and poured into crushed ice in a beaker. The chloroform layer was separated, washed with cold water and allowed to evaporate slowly. The residual 2-methyl-4-chlorobenzenesulfonylchloride was treated with 2-chloroaniline in a stoichiometric ratio and boiled for ten minutes. The reaction mixture was then cooled to room temperature and added to ice cold water (100 ml). The resultant solid 2-methyl-4-chloro-N-(2-chlorophenyl)-benzenesulfonamide was filtered under suction and washed thoroughly with cold water. It was then recrystallized to constant melting point from dilute ethanol. The purity of the compound was checked and characterized by recording its infrared and NMR spectra. The single crystals used in X-ray diffraction studies were grown from an ethanolic solution by slow evaporation at room temperature.

Computing details top

Data collection: CAD-4-PC (Enraf–Nonius, 1996); cell refinement: CAD-4-PC (Enraf–Nonius, 1996; data reduction: REDU4 (Stoe & Cie, 1987); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. Molecular structure of (I), showing the atom labeling scheme. The displacement ellipsoids are drawn at the 50% probability level. The H atoms are represented as small spheres of arbitrary radii.
	Fig. 2. Molecular packing of (I) with hydrogen bonding shown as dashed lines.

4-Chloro-N-(2-chlorophenyl)-2-methylbenzenesulfonamide top

Crystal data top

C₁₃H₁₁Cl₂NO₂S	Z = 2
M_r = 316.19	F(000) = 324
Triclinic, P1	D_x = 1.549 Mg m⁻³
Hall symbol: -P 1	Cu Kα radiation, λ = 1.54180 Å
a = 8.089 (2) Å	Cell parameters from 25 reflections
b = 8.096 (2) Å	θ = 5.7–19.7°
c = 10.946 (3) Å	µ = 5.73 mm⁻¹
α = 96.00 (1)°	T = 299 K
β = 97.11 (2)°	Plate, colourless
γ = 105.67 (2)°	0.45 × 0.33 × 0.08 mm
V = 677.7 (3) Å³

Data collection top

Enraf–Nonius CAD-4 diffractometer	1932 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.037
Graphite monochromator	θ_max = 66.9°, θ_min = 4.1°
ω scans	h = −9→1
Absorption correction: ψ scan (North et al., 1968)	k = −9→9
T_min = 0.150, T_max = 0.640	l = −12→13
2684 measured reflections	3 standard reflections every 120 min
2414 independent reflections	intensity decay: 1.0%

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.083	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.236	w = 1/[σ²(F_o²) + (0.179P)² + 0.1079P] where P = (F_o² + 2F_c²)/3
S = 1.05	(Δ/σ)_max = 0.008
2414 reflections	Δρ_max = 0.60 e Å⁻³
177 parameters	Δρ_min = −0.67 e Å⁻³
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.039 (6)

Crystal data top

C₁₃H₁₁Cl₂NO₂S	γ = 105.67 (2)°
M_r = 316.19	V = 677.7 (3) Å³
Triclinic, P1	Z = 2
a = 8.089 (2) Å	Cu Kα radiation
b = 8.096 (2) Å	µ = 5.73 mm⁻¹
c = 10.946 (3) Å	T = 299 K
α = 96.00 (1)°	0.45 × 0.33 × 0.08 mm
β = 97.11 (2)°

Data collection top

Enraf–Nonius CAD-4 diffractometer	1932 reflections with I > 2σ(I)
Absorption correction: ψ scan (North et al., 1968)	R_int = 0.037
T_min = 0.150, T_max = 0.640	3 standard reflections every 120 min
2684 measured reflections	intensity decay: 1.0%
2414 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.083	0 restraints
wR(F²) = 0.236	H atoms treated by a mixture of independent and constrained refinement
S = 1.05	Δρ_max = 0.60 e Å⁻³
2414 reflections	Δρ_min = −0.67 e Å⁻³
177 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
Cl1	0.35954 (18)	0.30027 (19)	0.56480 (12)	0.0932 (5)
Cl2	0.70514 (17)	0.48939 (15)	0.15780 (13)	0.0901 (5)
S1	0.71199 (12)	−0.00409 (12)	0.15693 (9)	0.0651 (4)
O1	0.8667 (4)	−0.0424 (4)	0.2054 (3)	0.0761 (8)
O2	0.5732 (4)	−0.1359 (4)	0.0795 (3)	0.0757 (8)
N1	0.7673 (4)	0.1494 (4)	0.0701 (3)	0.0659 (9)
H1N	0.678 (7)	0.178 (6)	0.034 (5)	0.079*
C1	0.6225 (5)	0.0807 (5)	0.2792 (4)	0.0637 (9)
C2	0.7215 (5)	0.1757 (5)	0.3907 (4)	0.0660 (10)
C3	0.6344 (6)	0.2423 (6)	0.4761 (4)	0.0719 (11)
H3	0.6974	0.3069	0.5507	0.086*
C4	0.4585 (6)	0.2158 (6)	0.4536 (4)	0.0708 (10)
C5	0.3607 (6)	0.1217 (6)	0.3426 (4)	0.0732 (11)
H5	0.2410	0.1036	0.3271	0.088*
C6	0.4441 (5)	0.0565 (5)	0.2569 (4)	0.0686 (10)
H6	0.3800	−0.0057	0.1818	0.082*
C7	0.9177 (5)	0.2931 (5)	0.1116 (4)	0.0625 (9)
C8	0.9064 (6)	0.4560 (5)	0.1521 (4)	0.0693 (10)
C9	1.0553 (7)	0.5950 (6)	0.1862 (4)	0.0812 (12)
H9	1.0466	0.7053	0.2114	0.097*
C10	1.2140 (6)	0.5692 (7)	0.1826 (5)	0.0900 (15)
H10	1.3139	0.6619	0.2069	0.108*
C11	1.2280 (6)	0.4087 (7)	0.1436 (5)	0.0900 (15)
H11	1.3372	0.3921	0.1427	0.108*
C12	1.0796 (6)	0.2698 (6)	0.1052 (5)	0.0760 (11)
H12	1.0891	0.1615	0.0753	0.091*
C13	0.9170 (6)	0.2092 (8)	0.4254 (4)	0.0875 (14)
H13A	0.9430	0.1011	0.4307	0.105*
H13B	0.9567	0.2823	0.5044	0.105*
H13C	0.9747	0.2655	0.3630	0.105*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cl1	0.0896 (9)	0.1076 (10)	0.0887 (9)	0.0410 (7)	0.0150 (6)	0.0072 (7)
Cl2	0.0869 (8)	0.0730 (8)	0.1186 (10)	0.0325 (6)	0.0255 (7)	0.0141 (6)
S1	0.0608 (6)	0.0547 (6)	0.0758 (7)	0.0165 (4)	−0.0011 (4)	0.0066 (4)
O1	0.0695 (18)	0.0690 (17)	0.093 (2)	0.0285 (14)	0.0023 (15)	0.0136 (14)
O2	0.0690 (17)	0.0601 (16)	0.0872 (19)	0.0119 (13)	−0.0024 (14)	−0.0020 (13)
N1	0.0591 (18)	0.0635 (19)	0.0692 (19)	0.0144 (14)	−0.0032 (14)	0.0074 (14)
C1	0.058 (2)	0.060 (2)	0.073 (2)	0.0185 (16)	−0.0008 (17)	0.0152 (17)
C2	0.061 (2)	0.071 (2)	0.065 (2)	0.0205 (17)	−0.0021 (17)	0.0108 (17)
C3	0.072 (2)	0.073 (2)	0.065 (2)	0.0210 (19)	−0.0043 (18)	0.0072 (18)
C4	0.075 (2)	0.070 (2)	0.071 (2)	0.0278 (19)	0.0071 (19)	0.0153 (18)
C5	0.062 (2)	0.079 (3)	0.079 (3)	0.0260 (19)	0.0022 (19)	0.013 (2)
C6	0.061 (2)	0.067 (2)	0.072 (2)	0.0168 (18)	−0.0026 (18)	0.0084 (17)
C7	0.058 (2)	0.062 (2)	0.063 (2)	0.0149 (16)	−0.0013 (15)	0.0093 (15)
C8	0.072 (2)	0.065 (2)	0.068 (2)	0.0178 (18)	0.0016 (18)	0.0123 (17)
C9	0.087 (3)	0.067 (2)	0.077 (3)	0.006 (2)	0.000 (2)	0.0105 (19)
C10	0.070 (3)	0.086 (3)	0.095 (3)	−0.005 (2)	−0.011 (2)	0.025 (2)
C11	0.061 (2)	0.094 (3)	0.109 (4)	0.014 (2)	−0.005 (2)	0.032 (3)
C12	0.062 (2)	0.080 (3)	0.089 (3)	0.023 (2)	0.008 (2)	0.022 (2)
C13	0.062 (3)	0.114 (4)	0.075 (3)	0.022 (2)	−0.008 (2)	−0.003 (2)

Geometric parameters (Å, º) top

Cl1—C4	1.719 (5)	C5—H5	0.9300
Cl2—C8	1.728 (5)	C6—H6	0.9300
S1—O1	1.423 (3)	C7—C8	1.378 (6)
S1—O2	1.430 (3)	C7—C12	1.381 (6)
S1—N1	1.643 (4)	C8—C9	1.388 (6)
S1—C1	1.761 (4)	C9—C10	1.360 (8)
N1—C7	1.424 (5)	C9—H9	0.9300
N1—H1N	0.88 (5)	C10—C11	1.364 (8)
C1—C6	1.390 (5)	C10—H10	0.9300
C1—C2	1.398 (5)	C11—C12	1.389 (6)
C2—C3	1.387 (7)	C11—H11	0.9300
C2—C13	1.522 (6)	C12—H12	0.9300
C3—C4	1.366 (6)	C13—H13A	0.9600
C3—H3	0.9300	C13—H13B	0.9600
C4—C5	1.388 (6)	C13—H13C	0.9600
C5—C6	1.364 (7)

O1—S1—O2	120.08 (19)	C1—C6—H6	119.2
O1—S1—N1	107.27 (18)	C8—C7—C12	119.1 (4)
O2—S1—N1	104.75 (18)	C8—C7—N1	122.1 (4)
O1—S1—C1	109.99 (19)	C12—C7—N1	118.8 (4)
O2—S1—C1	106.96 (19)	C7—C8—C9	120.6 (4)
N1—S1—C1	107.03 (18)	C7—C8—Cl2	120.0 (3)
C7—N1—S1	120.4 (3)	C9—C8—Cl2	119.4 (4)
C7—N1—H1N	114 (3)	C10—C9—C8	119.6 (5)
S1—N1—H1N	113 (3)	C10—C9—H9	120.2
C6—C1—C2	120.1 (4)	C8—C9—H9	120.2
C6—C1—S1	116.1 (3)	C9—C10—C11	120.6 (4)
C2—C1—S1	123.7 (3)	C9—C10—H10	119.7
C3—C2—C1	117.4 (4)	C11—C10—H10	119.7
C3—C2—C13	118.0 (4)	C10—C11—C12	120.2 (5)
C1—C2—C13	124.6 (4)	C10—C11—H11	119.9
C4—C3—C2	121.9 (4)	C12—C11—H11	119.9
C4—C3—H3	119.0	C7—C12—C11	119.8 (5)
C2—C3—H3	119.0	C7—C12—H12	120.1
C3—C4—C5	120.6 (4)	C11—C12—H12	120.1
C3—C4—Cl1	119.2 (4)	C2—C13—H13A	109.5
C5—C4—Cl1	120.3 (4)	C2—C13—H13B	109.5
C6—C5—C4	118.5 (4)	H13A—C13—H13B	109.5
C6—C5—H5	120.8	C2—C13—H13C	109.5
C4—C5—H5	120.8	H13A—C13—H13C	109.5
C5—C6—C1	121.6 (4)	H13B—C13—H13C	109.5
C5—C6—H6	119.2

O1—S1—N1—C7	−43.2 (4)	Cl1—C4—C5—C6	−179.9 (3)
O2—S1—N1—C7	−171.9 (3)	C4—C5—C6—C1	0.7 (6)
C1—S1—N1—C7	74.8 (4)	C2—C1—C6—C5	−0.9 (6)
O1—S1—C1—C6	−153.8 (3)	S1—C1—C6—C5	−177.6 (3)
O2—S1—C1—C6	−21.8 (3)	S1—N1—C7—C8	−106.8 (4)
N1—S1—C1—C6	90.0 (3)	S1—N1—C7—C12	76.4 (5)
O1—S1—C1—C2	29.7 (4)	C12—C7—C8—C9	−0.1 (6)
O2—S1—C1—C2	161.6 (3)	N1—C7—C8—C9	−176.9 (4)
N1—S1—C1—C2	−86.6 (4)	C12—C7—C8—Cl2	178.6 (3)
C6—C1—C2—C3	0.2 (6)	N1—C7—C8—Cl2	1.9 (6)
S1—C1—C2—C3	176.7 (3)	C7—C8—C9—C10	−1.7 (7)
C6—C1—C2—C13	179.5 (4)	Cl2—C8—C9—C10	179.6 (4)
S1—C1—C2—C13	−4.0 (6)	C8—C9—C10—C11	1.2 (8)
C1—C2—C3—C4	0.6 (6)	C9—C10—C11—C12	1.0 (8)
C13—C2—C3—C4	−178.8 (4)	C8—C7—C12—C11	2.3 (6)
C2—C3—C4—C5	−0.7 (7)	N1—C7—C12—C11	179.2 (4)
C2—C3—C4—Cl1	179.2 (3)	C10—C11—C12—C7	−2.7 (7)
C3—C4—C5—C6	0.1 (6)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1N···O2ⁱ	0.88 (5)	2.17 (5)	2.994 (5)	157 (4)
N1—H1N···Cl2	0.88 (5)	2.67 (5)	3.011 (4)	104 (4)

Symmetry code: (i) −x+1, −y, −z.

Experimental details

Crystal data
Chemical formula	C₁₃H₁₁Cl₂NO₂S
M_r	316.19
Crystal system, space group	Triclinic, P1
Temperature (K)	299
a, b, c (Å)	8.089 (2), 8.096 (2), 10.946 (3)
α, β, γ (°)	96.00 (1), 97.11 (2), 105.67 (2)
V (Å³)	677.7 (3)
Z	2
Radiation type	Cu Kα
µ (mm⁻¹)	5.73
Crystal size (mm)	0.45 × 0.33 × 0.08

Data collection
Diffractometer	Enraf–Nonius CAD-4 diffractometer
Absorption correction	ψ scan (North et al., 1968)
T_min, T_max	0.150, 0.640
No. of measured, independent and observed [I > 2σ(I)] reflections	2684, 2414, 1932
R_int	0.037
(sin θ/λ)_max (Å⁻¹)	0.597

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.083, 0.236, 1.05
No. of reflections	2414
No. of parameters	177
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.60, −0.67

Computer programs: CAD-4-PC (Enraf–Nonius, 1996), CAD-4-PC (Enraf–Nonius, 1996, REDU4 (Stoe & Cie, 1987), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1N···O2ⁱ	0.88 (5)	2.17 (5)	2.994 (5)	157 (4)
N1—H1N···Cl2	0.88 (5)	2.67 (5)	3.011 (4)	104 (4)

Symmetry code: (i) −x+1, −y, −z.

References

Enraf–Nonius (1996). CAD-4-PC. Enraf–Nonius, Delft, The Netherlands. Google Scholar
Gelbrich, T., Hursthouse, M. B. & Threlfall, T. L. (2007). Acta Cryst. B63, 621–632. Web of Science CSD CrossRef IUCr Journals Google Scholar
Gowda, B. T., Foro, S., Nirmala, P. G., Babitha, K. S. & Fuess, H. (2009a). Acta Cryst. E65, o476. Web of Science CSD CrossRef IUCr Journals Google Scholar
Gowda, B. T., Foro, S., Nirmala, P. G., Babitha, K. S. & Fuess, H. (2009b). Acta Cryst. E65, o576. Web of Science CSD CrossRef IUCr Journals Google Scholar
North, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351–359. CrossRef IUCr Journals Web of Science Google Scholar
Perlovich, G. L., Tkachev, V. V., Schaper, K.-J. & Raevsky, O. A. (2006). Acta Cryst. E62, o780–o782. Web of Science CSD CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Spek, A. L. (2009). Acta Cryst. D65, 148–155. Web of Science CrossRef CAS IUCr Journals Google Scholar
Stoe & Cie (1987). REDU4. Stoe & Cie GmbH, Darmstadt, Germany. Google Scholar

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Volume 65| Part 4| April 2009| Page o717

doi:10.1107/S1600536809007880

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