4-Bromo-N-(3,4,5-trimethoxy­benzyl­idene)aniline

Khalaji, A.D.; Weil, M.; Gotoh, K.; Ishida, H.

doi:10.1107/S1600536809003432

organic compounds

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ISSN: 2056-9890

Volume 65| Part 2| February 2009| Page o436

doi:10.1107/S1600536809003432

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4-Bromo-N-(3,4,5-trimethoxybenzylidene)aniline

Aliakbar Dehno Khalaji,^a ‡ Matthias Weil,^b Kazuma Gotoh ^c and Hiroyuki Ishida ^c ^*

^aDepartment of Chemistry, Faculty of Science, Golestan University, Gorgan, Iran, ^bInstitute for Chemical Technology and Analytics, Division of Structural Chemistry, Vienna University of Technology, Getreidemarkt 9/164-SC, A-1060 Vienna, Austria, and ^cDepartment of Chemistry, Faculty of Science, Okayama University, Okayama 700-8530, Japan
^*Correspondence e-mail: ishidah@cc.okayama-u.ac.jp

(Received 26 January 2009; accepted 28 January 2009; online 31 January 2009)

The title compound, C₁₆H₁₆BrNO₃, adopts an E configuration with respect to the imine C=N bond. The two benzene rings are twisted with respect to each other at an angle of 38.3 (1)°. In the crystal structure, molecules are connected by weak bifurcated C—H⋯(O, O) hydrogen bonds, forming a helical chain along the b axis.

Related literature

The structure of the isotypic 4-chloro compound was reported by Khalaji et al. (2009 ). For structures containing a 4-bromoaniline unit, see: Khalaji et al. (2007 ); Khalaji & Harrison (2008 ).

Experimental

Crystal data

C₁₆H₁₆BrNO₃
M_r = 350.21
Monoclinic, P 2₁
a = 7.1951 (4) Å
b = 8.3722 (5) Å
c = 13.2882 (8) Å
β = 104.413 (3)°
V = 775.27 (8) Å³
Z = 2
Mo Kα radiation
μ = 2.66 mm⁻¹
T = 296 (2) K
0.40 × 0.30 × 0.15 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2006 ) T_min = 0.403, T_max = 0.671
18229 measured reflections
3497 independent reflections
3064 reflections with I > 2σ(I)
R_int = 0.023

Refinement

R[F² > 2σ(F²)] = 0.025
wR(F²) = 0.065
S = 1.09
3497 reflections
193 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.30 e Å⁻³
Δρ_min = −0.53 e Å⁻³
Absolute structure: Flack (1983 ), 1511 Friedel pairs
Flack parameter: 0.012 (6)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C7—H7⋯O1ⁱ	0.93	2.63	3.272 (2)	127
C7—H7⋯O2ⁱ	0.93	2.63	3.553 (3)	172
Symmetry code: (i) $[-x, y+{\script{1\over 2}}, -z+1]$ .

Data collection: APEX2 (Bruker, 2008 ); cell refinement: SAINT (Bruker, 2008); 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 ); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2003 ).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809003432/wn2308sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809003432/wn2308Isup2.hkl

checkCIF report

Comment top

Recently, we reported two Schiff-base compounds with 4-bromoaniline units that have been structurally characterized (Khalaji et al., 2007; Khalaji & Harrison, 2008). In continuation of these studies, the title compound was prepared and its structure has been determined.

An ORTEP plot, with the atomic numbering scheme is depicted in Fig. 1. The two benzene rings are twisted with respect to each other at an angle of 38.3 (1)°. In the crystal structure, the molecules are connected by weak bifurcated C—H···(O, O) hydrogen bonds, forming a helical chain along the b axis.

The C7═N1 bond length of 1.268 (3) Å conforms to the value for a double bond, and is slightly shorter than the corresponding bond length in N-(2-benzylidenepropylidene)-4-bromoaniline [C23═N23 1.288 (6) Å; Khalaji et al., 2007] and β-phenylcinnamaldehyde-4-bromoaniline [C7═N1 1.277 (4) Å; Khalaji & Harrison, 2008]. The C4—N1 bond length of 1.421 (2) Å conforms to the value for a single bond, and, in turn, is slightly longer than the corresponding bond length in N-(2-benzylidenepropylidene)-4-bromoaniline [C24—N23 1.411 (7) Å] and β-phenylcinnamaldehyde-4-bromoaniline [C6—N1 1.407 (4) Å]. All other bond lengths in the three related Schiff-base compounds are quite similar. For the title compound, the torsion angle, C8—C7—N1—C4, is 179.20 (18)°, indicating a virtually planar E-configuration with respect to the imine C═N bond (Khalaji et al., 2007; Khalaji & Harrison, 2008).

In comparison with the isotypic structure of C₁₆H₁₆ClNO₃ (Dehno Khalaji et al., 2009), all interatomic distances and angles (except those involving the halogen atom) are very similar.

Related literature top

The structure of the isotypic 4-chloro compound was reported by Dehno Khalaji et al. (2009). For structures containing a 4-bromoaniline unit, see: Khalaji et al. (2007); Khalaji & Harrison (2008).

Experimental top

The title compound was prepared by the reaction of 3,4,5-trimethoxybenzaldehyde (1 mmol, 0.196 g) and 4-bromoaniline (1 mmol, 0.172 g), which were dissolved in methanol (10 ml). The mixture was stirred at room temperature for 30 min. Colourless single crystals suitable for X-ray structure analysis were obtained by recrystallization from a methanol/chloroform (1:1 v/v) solution.

Computing details top

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2003).

Figures top

	Fig. 1. The molecular structure of the title compound, with the atom-labelling. Displacement ellipsoids of non-H atoms are drawn at the 50% probability level. Hydrogen atoms are denoted by spheres of arbitrary radius.
	Fig. 2. A partial packing diagram, viewed along the a axis. H atoms not involved in the C—H···O hydrogen bonds have been omitted.

4-Bromo-N-(3,4,5-trimethoxybenzylidene)aniline top

Crystal data top

C₁₆H₁₆BrNO₃	F(000) = 356
M_r = 350.21	D_x = 1.500 Mg m⁻³
Monoclinic, P2₁	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2yb	Cell parameters from 9957 reflections
a = 7.1951 (4) Å	θ = 2.9–29.0°
b = 8.3722 (5) Å	µ = 2.66 mm⁻¹
c = 13.2882 (8) Å	T = 296 K
β = 104.413 (3)°	Block, colourless
V = 775.27 (8) Å³	0.40 × 0.30 × 0.15 mm
Z = 2

Data collection top

Bruker APEXII CCD diffractometer	3497 independent reflections
Radiation source: fine-focus sealed tube	3064 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.023
ω scans	θ_max = 28.0°, θ_min = 2.9°
Absorption correction: multi-scan (SADABS; Bruker, 2006)	h = −9→9
T_min = 0.403, T_max = 0.671	k = −10→10
18229 measured reflections	l = −17→17

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)] = 0.025	H-atom parameters constrained
wR(F²) = 0.065	w = 1/[σ²(F_o²) + (0.0339P)² + 0.0173P] where P = (F_o² + 2F_c²)/3
S = 1.09	(Δ/σ)_max = 0.002
3497 reflections	Δρ_max = 0.30 e Å⁻³
193 parameters	Δρ_min = −0.53 e Å⁻³
1 restraint	Absolute structure: Flack (1983), 1511 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.012 (6)

Crystal data top

C₁₆H₁₆BrNO₃	V = 775.27 (8) Å³
M_r = 350.21	Z = 2
Monoclinic, P2₁	Mo Kα radiation
a = 7.1951 (4) Å	µ = 2.66 mm⁻¹
b = 8.3722 (5) Å	T = 296 K
c = 13.2882 (8) Å	0.40 × 0.30 × 0.15 mm
β = 104.413 (3)°

Data collection top

Bruker APEXII CCD diffractometer	3497 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2006)	3064 reflections with I > 2σ(I)
T_min = 0.403, T_max = 0.671	R_int = 0.023
18229 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.025	H-atom parameters constrained
wR(F²) = 0.065	Δρ_max = 0.30 e Å⁻³
S = 1.09	Δρ_min = −0.53 e Å⁻³
3497 reflections	Absolute structure: Flack (1983), 1511 Friedel pairs
193 parameters	Absolute structure parameter: 0.012 (6)
1 restraint

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
Br1	0.99402 (3)	0.96811 (5)	0.988948 (16)	0.06694 (9)
O1	−0.26888 (18)	0.4772 (2)	0.36904 (9)	0.0522 (3)
O2	−0.46171 (19)	0.29368 (19)	0.46988 (11)	0.0498 (3)
O3	−0.3668 (2)	0.2687 (2)	0.67538 (12)	0.0600 (4)
N1	0.2656 (2)	0.6014 (2)	0.79047 (14)	0.0502 (4)
C1	0.7715 (3)	0.8470 (2)	0.92769 (15)	0.0450 (4)
C2	0.6245 (3)	0.8386 (3)	0.97682 (18)	0.0595 (6)
H2	0.6355	0.8891	1.0404	0.071*
C3	0.4614 (4)	0.7546 (3)	0.9308 (2)	0.0604 (6)
H3	0.3634	0.7458	0.9648	0.072*
C4	0.4402 (3)	0.6827 (2)	0.83465 (15)	0.0436 (4)
C5	0.5939 (3)	0.6886 (3)	0.78856 (16)	0.0478 (5)
H5	0.5850	0.6368	0.7256	0.057*
C6	0.7594 (3)	0.7705 (3)	0.83532 (17)	0.0498 (5)
H6	0.8618	0.7736	0.8043	0.060*
C7	0.2013 (3)	0.6071 (2)	0.69260 (16)	0.0427 (4)
H7	0.2700	0.6651	0.6542	0.051*
C8	0.0246 (3)	0.5272 (2)	0.63686 (16)	0.0411 (4)
C9	−0.0833 (3)	0.4364 (2)	0.69019 (15)	0.0432 (5)
H9	−0.0454	0.4266	0.7621	0.052*
C10	−0.2484 (3)	0.3611 (2)	0.63335 (16)	0.0430 (4)
C11	−0.3059 (3)	0.3758 (2)	0.52599 (16)	0.0411 (4)
C12	−0.1991 (2)	0.4695 (3)	0.47377 (12)	0.0403 (3)
C13	−0.0336 (3)	0.5450 (2)	0.53043 (16)	0.0417 (4)
H13	0.0381	0.6078	0.4963	0.050*
C14	−0.1666 (4)	0.5679 (4)	0.3108 (2)	0.0785 (8)
H14A	−0.1641	0.6779	0.3316	0.118*
H14B	−0.2287	0.5591	0.2382	0.118*
H14C	−0.0377	0.5284	0.3232	0.118*
C15	−0.6378 (3)	0.3769 (4)	0.4588 (2)	0.0673 (7)
H15A	−0.6588	0.3972	0.5262	0.101*
H15B	−0.7412	0.3133	0.4189	0.101*
H15C	−0.6324	0.4765	0.4238	0.101*
C16	−0.3111 (5)	0.2366 (4)	0.7828 (2)	0.0761 (8)
H16A	−0.1813	0.1983	0.8010	0.114*
H16B	−0.3944	0.1569	0.7997	0.114*
H16C	−0.3198	0.3327	0.8208	0.114*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Br1	0.05738 (13)	0.06441 (15)	0.06520 (14)	−0.01188 (12)	−0.01083 (9)	−0.00513 (15)
O1	0.0556 (7)	0.0567 (8)	0.0431 (6)	−0.0113 (9)	0.0100 (5)	−0.0013 (9)
O2	0.0463 (7)	0.0467 (8)	0.0547 (8)	−0.0096 (7)	0.0092 (6)	−0.0106 (7)
O3	0.0588 (9)	0.0704 (10)	0.0506 (9)	−0.0236 (7)	0.0135 (7)	0.0033 (7)
N1	0.0478 (9)	0.0533 (10)	0.0498 (11)	−0.0107 (8)	0.0126 (8)	−0.0056 (8)
C1	0.0423 (9)	0.0395 (11)	0.0456 (11)	−0.0019 (8)	−0.0036 (8)	−0.0007 (8)
C2	0.0630 (13)	0.0664 (15)	0.0468 (12)	−0.0018 (11)	0.0094 (10)	−0.0168 (10)
C3	0.0582 (13)	0.0769 (18)	0.0500 (14)	−0.0086 (11)	0.0208 (11)	−0.0114 (10)
C4	0.0425 (9)	0.0441 (12)	0.0418 (10)	−0.0030 (9)	0.0060 (8)	−0.0009 (8)
C5	0.0463 (10)	0.0538 (14)	0.0400 (11)	−0.0014 (10)	0.0044 (8)	−0.0099 (9)
C6	0.0408 (10)	0.0595 (14)	0.0466 (12)	−0.0002 (9)	0.0060 (9)	−0.0020 (10)
C7	0.0376 (9)	0.0393 (10)	0.0504 (12)	−0.0019 (8)	0.0095 (8)	−0.0013 (8)
C8	0.0355 (9)	0.0337 (9)	0.0524 (11)	0.0014 (7)	0.0076 (8)	−0.0044 (7)
C9	0.0418 (9)	0.0433 (13)	0.0442 (9)	−0.0024 (7)	0.0101 (7)	−0.0026 (7)
C10	0.0434 (10)	0.0377 (11)	0.0497 (11)	−0.0038 (8)	0.0148 (8)	−0.0041 (8)
C11	0.0378 (9)	0.0345 (10)	0.0503 (11)	−0.0006 (8)	0.0097 (8)	−0.0080 (8)
C12	0.0412 (8)	0.0356 (8)	0.0449 (8)	0.0025 (11)	0.0122 (6)	−0.0028 (11)
C13	0.0397 (9)	0.0371 (10)	0.0502 (11)	−0.0020 (7)	0.0148 (8)	−0.0011 (8)
C14	0.0817 (17)	0.102 (2)	0.0505 (14)	−0.0239 (16)	0.0142 (13)	0.0169 (14)
C15	0.0429 (11)	0.0708 (17)	0.0828 (18)	−0.0044 (12)	0.0056 (11)	−0.0027 (13)
C16	0.0790 (17)	0.086 (2)	0.0611 (18)	−0.0228 (16)	0.0134 (15)	0.0180 (13)

Geometric parameters (Å, º) top

Br1—C1	1.8992 (19)	C7—C8	1.464 (3)
O1—C12	1.358 (2)	C7—H7	0.9300
O1—C14	1.414 (3)	C8—C9	1.399 (3)
O2—C11	1.367 (2)	C8—C13	1.379 (3)
O2—C15	1.421 (3)	C9—H9	0.9300
O3—C16	1.409 (3)	C10—C9	1.390 (3)
O3—C10	1.368 (2)	C11—C10	1.388 (3)
C1—C2	1.376 (3)	C12—C13	1.392 (3)
C1—C6	1.368 (3)	C12—C11	1.397 (3)
C2—H2	0.9300	C13—H13	0.9300
C3—C2	1.375 (3)	C14—H14A	0.9600
C3—H3	0.9300	C14—H14B	0.9600
C4—N1	1.421 (2)	C14—H14C	0.9600
C4—C3	1.386 (3)	C15—H15A	0.9600
C4—C5	1.392 (3)	C15—H15B	0.9600
C5—C6	1.380 (3)	C15—H15C	0.9600
C5—H5	0.9300	C16—H16A	0.9600
C6—H6	0.9300	C16—H16B	0.9600
C7—N1	1.268 (3)	C16—H16C	0.9600

O1—C12—C11	115.25 (16)	C6—C1—Br1	119.56 (16)
O1—C12—C13	125.52 (17)	C6—C1—C2	121.14 (18)
O1—C14—H14A	109.5	C6—C5—C4	120.69 (19)
O1—C14—H14B	109.5	C6—C5—H5	119.7
O1—C14—H14C	109.5	C7—N1—C4	117.70 (17)
O2—C11—C10	120.65 (17)	C8—C7—H7	118.3
O2—C11—C12	119.28 (17)	C8—C9—H9	120.7
O2—C15—H15A	109.5	C8—C13—C12	120.43 (18)
O2—C15—H15B	109.5	C8—C13—H13	119.8
O2—C15—H15C	109.5	C9—C8—C7	120.90 (18)
O3—C10—C9	124.70 (18)	C10—O3—C16	118.18 (19)
O3—C10—C11	114.39 (17)	C10—C9—C8	118.58 (18)
O3—C16—H16A	109.5	C10—C9—H9	120.7
O3—C16—H16B	109.5	C10—C11—C12	120.00 (17)
O3—C16—H16C	109.5	C11—O2—C15	113.49 (18)
N1—C7—C8	123.41 (18)	C11—C10—C9	120.91 (17)
N1—C7—H7	118.3	C12—O1—C14	118.41 (17)
C1—C2—H2	120.4	C13—C8—C9	120.83 (17)
C1—C6—C5	119.45 (19)	C13—C8—C7	118.27 (17)
C1—C6—H6	120.3	C13—C12—C11	119.23 (16)
C2—C1—Br1	119.30 (15)	C12—C13—H13	119.8
C2—C3—C4	121.2 (2)	H14A—C14—H14B	109.5
C2—C3—H3	119.4	H14A—C14—H14C	109.5
C3—C2—C1	119.1 (2)	H14B—C14—H14C	109.5
C3—C2—H2	120.4	H15A—C15—H15B	109.5
C3—C4—N1	118.17 (18)	H15A—C15—H15C	109.5
C3—C4—C5	118.22 (19)	H15B—C15—H15C	109.5
C4—C3—H3	119.4	H16A—C16—H16B	109.5
C4—C5—H5	119.7	H16A—C16—H16C	109.5
C5—C4—N1	123.56 (17)	H16B—C16—H16C	109.5
C5—C6—H6	120.3

Br1—C1—C2—C3	178.2 (2)	C6—C1—C2—C3	−1.4 (4)
Br1—C1—C6—C5	−177.04 (17)	C7—C8—C9—C10	−179.05 (17)
O1—C12—C11—O2	3.6 (3)	C7—C8—C13—C12	179.05 (18)
O1—C12—C11—C10	−179.35 (19)	C8—C7—N1—C4	179.19 (18)
O1—C12—C13—C8	−179.36 (19)	C9—C10—O3—C16	−5.2 (3)
O2—C11—C10—O3	−4.2 (3)	C9—C8—C13—C12	−1.5 (3)
O2—C11—C10—C9	175.96 (17)	C11—C10—O3—C16	174.9 (2)
O3—C10—C9—C8	179.93 (18)	C11—C12—C13—C8	0.2 (3)
N1—C4—C3—C2	−178.3 (2)	C11—C10—C9—C8	−0.2 (3)
N1—C4—C5—C6	179.6 (2)	C12—C11—C10—O3	178.83 (19)
N1—C7—C8—C13	178.51 (19)	C12—C11—C10—C9	−1.0 (3)
N1—C7—C8—C9	−0.9 (3)	C13—C8—C9—C10	1.5 (3)
C2—C1—C6—C5	2.6 (3)	C13—C12—C11—O2	−175.99 (19)
C3—C4—N1—C7	144.8 (2)	C13—C12—C11—C10	1.0 (3)
C3—C4—C5—C6	−3.0 (3)	C14—O1—C12—C11	−179.1 (2)
C4—C3—C2—C1	−2.0 (4)	C14—O1—C12—C13	0.5 (3)
C4—C5—C6—C1	−0.3 (4)	C15—O2—C11—C10	88.3 (2)
C5—C4—C3—C2	4.2 (4)	C15—O2—C11—C12	−94.7 (2)
C5—C4—N1—C7	−37.8 (3)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C7—H7···O1ⁱ	0.93	2.63	3.272 (2)	127
C7—H7···O2ⁱ	0.93	2.63	3.553 (3)	172

Symmetry code: (i) −x, y+1/2, −z+1.

Experimental details

Crystal data
Chemical formula	C₁₆H₁₆BrNO₃
M_r	350.21
Crystal system, space group	Monoclinic, P2₁
Temperature (K)	296
a, b, c (Å)	7.1951 (4), 8.3722 (5), 13.2882 (8)
β (°)	104.413 (3)
V (Å³)	775.27 (8)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	2.66
Crystal size (mm)	0.40 × 0.30 × 0.15

Data collection
Diffractometer	Bruker APEXII CCD diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2006)
T_min, T_max	0.403, 0.671
No. of measured, independent and observed [I > 2σ(I)] reflections	18229, 3497, 3064
R_int	0.023
(sin θ/λ)_max (Å⁻¹)	0.661

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.025, 0.065, 1.09
No. of reflections	3497
No. of parameters	193
No. of restraints	1
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.30, −0.53
Absolute structure	Flack (1983), 1511 Friedel pairs
Absolute structure parameter	0.012 (6)

Computer programs: APEX2 (Bruker, 2008), SAINT (Bruker, 2008), SHELXS97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997), SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2003).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C7—H7···O1ⁱ	0.93	2.63	3.272 (2)	127
C7—H7···O2ⁱ	0.93	2.63	3.553 (3)	172

Symmetry code: (i) −x, y+1/2, −z+1.

Footnotes

‡Additional correspondence author, e-mail: alidkhalaji@yahoo.com.

References

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