(E)-3-(2-Chloro­phen­yl)-1-(3-methoxy­phen­yl)prop-2-en-1-one

Fun, H.-K.; Jebas, S.R.; Patil, P.S.; Dharmaprakash, S.M.

doi:10.1107/S1600536808021910

organic compounds

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ISSN: 2056-9890

Volume 64| Part 8| August 2008| Page o1525

doi:10.1107/S1600536808021910

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(E)-3-(2-Chlorophenyl)-1-(3-methoxyphenyl)prop-2-en-1-one

Hoong-Kun Fun,^a ^* Samuel Robinson Jebas,^a ‡ P. S. Patil ^b and S. M. Dharmaprakash ^b

^aX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia, and ^bDepartment of Studies in Physics, Mangalore University, Mangalagangotri, Mangalore 574 199, India
^*Correspondence e-mail: hkfun@usm.my

(Received 10 July 2008; accepted 14 July 2008; online 19 July 2008)

The title compound, C₁₆H₁₃ClO₂, adopts an E configuration with respect to the double bond of the propenone unit. The two benzene rings are twisted slightly from each other, making a dihedral angle of 7.14 (5)°. The molecules are arranged in stacks, in which adjacent molecules are related by inversion symmetry and form π–π interactions with a centroid–centroid distance of 3.7098 (6) Å. C—H⋯O and C—H⋯π interactions are formed between neighbouring molecules.

Related literature

For related literature, see: Chantrapromma et al. (2005 , 2006 ); Fun et al. (2006 ); Patil, Fun et al. (2007 ); Patil, Dharmaprakash et al. (2006 , 2007 ).

Experimental

Crystal data

C₁₆H₁₃ClO₂
M_r = 272.71
Triclinic, $[P \overline 1]$
a = 7.7352 (2) Å
b = 8.1405 (2) Å
c = 10.7411 (2) Å
α = 87.392 (1)°
β = 82.147 (1)°
γ = 74.794 (1)°
V = 646.52 (3) Å³
Z = 2
Mo Kα radiation
μ = 0.29 mm⁻¹
T = 100.0 (1) K
0.38 × 0.30 × 0.16 mm

Data collection

Bruker SMART APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ) T_min = 0.899, T_max = 0.955
17497 measured reflections
4314 independent reflections
3644 reflections with I > 2σ(I)
R_int = 0.025

Refinement

R[F² > 2σ(F²)] = 0.037
wR(F²) = 0.101
S = 1.06
4314 reflections
173 parameters
H-atom parameters constrained
Δρ_max = 0.53 e Å⁻³
Δρ_min = −0.23 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

Cg1 is the centroid of the C1–C6 ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C2—H2A⋯O2ⁱ	0.93	2.50	3.3887 (13)	161
C4—H4A⋯O1ⁱⁱ	0.93	2.57	3.3003 (13)	136
C16—H16B⋯O1ⁱⁱⁱ	0.96	2.58	3.4899 (14)	158
C16—H16C⋯Cg1^iv	0.96	2.82	3.6137 (14)	135
Symmetry codes: (i) x+1, y-1, z-1; (ii) x+1, y-1, z; (iii) -x+1, -y+1, -z; (iv) -x+2, -y+1, -z.

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2003 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808021910/bi2296sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808021910/bi2296Isup2.hkl

checkCIF report

Comment top

As a part of our ongoing investigation of non-linear optical (NLO) compounds (Chantrapromma et al., 2005, 2006; Fun et al., 2006; Patil, Fun et al., 2007; Patil, Dharmaprakash et al., 2006, 2007), the title compound has recently been prepared in our laboratory and its crystal structure is presented here.

The molecule exhibits an E configuration with respect to the C7=C8 double bond, the torsion angle being C7—C8—C9—C10 = -166.3 (9)°. The dihedral angle between the two phenyl rings is 7.14 (5)°, indicating that they are slightly twisted from each other. The molecules are interconnected by weak C—H···O interactions and the packing is further consolidated by C–H···π and π–π interactions between the C1—C6 (centroid Cg1) and C10—C15 (centroid Cg2) rings: Cg1···Cg2ⁱ = 3.7098 (6) Å [symmetry code: (i) 2 - x, -y, -z].

Related literature top

For related literature, see: Chantrapromma et al. (2005, 2006); Fun et al. (2006); Patil, Fun et al. (2007); Patil, Dharmaprakash et al. (2006, 2007). Cg1 is the centroid of the C1–C6 ring.

Experimental top

2-Chlorobenzaldehyde (0.01 mol, 1.13 g) in ethanol (20 ml) was mixed with 3-methoxyacetophenone (0.01 mol, 1.37 ml) in 20 ml ethanol and the mixture was treated with 10 ml of 10% sodium hydroxide solution and stirred at room temperature for 8 h. The precipitate obtained was poured into ice-cold water (500 ml) and left to stand for 5 h. The resulting crude solid was filtered, dried and recrystallized from N,N-dimethylformamide by slow evaporation.

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2003).

Figures top

	Fig. 1. The molecular structure of the title compound, showing 50% probability displacement ellipsoids for non-H atoms.
	Fig. 2. Crystal packing of the title compound, viewed along the c axis. Hydrogen bonds are shown as dashed lines.

(I) top

Crystal data top

C₁₆H₁₃ClO₂	Z = 2
M_r = 272.71	F(000) = 284
Triclinic, P1	D_x = 1.401 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.7352 (2) Å	Cell parameters from 7792 reflections
b = 8.1405 (2) Å	θ = 2.2–37.5°
c = 10.7411 (2) Å	µ = 0.29 mm⁻¹
α = 87.392 (1)°	T = 100 K
β = 82.147 (1)°	Block, colourless
γ = 74.794 (1)°	0.38 × 0.30 × 0.16 mm
V = 646.52 (3) Å³

Data collection top

Bruker SMART APEXII CCD diffractometer	4314 independent reflections
Radiation source: fine-focus sealed tube	3644 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.025
ϕ and ω scans	θ_max = 31.7°, θ_min = 2.6°
Absorption correction: multi-scan (SADABS; Bruker, 2005)	h = −11→10
T_min = 0.899, T_max = 0.955	k = −11→12
17497 measured reflections	l = −15→15

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)] = 0.037	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.101	H-atom parameters constrained
S = 1.06	w = 1/[σ²(F_o²) + (0.0513P)² + 0.1689P] where P = (F_o² + 2F_c²)/3
4314 reflections	(Δ/σ)_max = 0.001
173 parameters	Δρ_max = 0.53 e Å⁻³
0 restraints	Δρ_min = −0.23 e Å⁻³

Crystal data top

C₁₆H₁₃ClO₂	γ = 74.794 (1)°
M_r = 272.71	V = 646.52 (3) Å³
Triclinic, P1	Z = 2
a = 7.7352 (2) Å	Mo Kα radiation
b = 8.1405 (2) Å	µ = 0.29 mm⁻¹
c = 10.7411 (2) Å	T = 100 K
α = 87.392 (1)°	0.38 × 0.30 × 0.16 mm
β = 82.147 (1)°

Data collection top

Bruker SMART APEXII CCD diffractometer	4314 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2005)	3644 reflections with I > 2σ(I)
T_min = 0.899, T_max = 0.955	R_int = 0.025
17497 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.037	0 restraints
wR(F²) = 0.101	H-atom parameters constrained
S = 1.06	Δρ_max = 0.53 e Å⁻³
4314 reflections	Δρ_min = −0.23 e Å⁻³
173 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	1.15204 (4)	0.08594 (3)	−0.41471 (2)	0.02216 (8)
O1	0.78728 (11)	0.44819 (10)	−0.05788 (8)	0.02200 (17)
O2	0.46589 (11)	0.70028 (11)	0.36344 (8)	0.02281 (17)
C1	1.29054 (14)	−0.01282 (13)	−0.30363 (10)	0.01529 (19)
C2	1.44112 (15)	−0.14294 (13)	−0.34590 (10)	0.0184 (2)
H2A	1.4678	−0.1705	−0.4307	0.022*
C3	1.55059 (15)	−0.23075 (13)	−0.25988 (11)	0.0196 (2)
H3A	1.6517	−0.3178	−0.2870	0.024*
C4	1.51011 (15)	−0.18945 (13)	−0.13323 (11)	0.0189 (2)
H4A	1.5830	−0.2495	−0.0755	0.023*
C5	1.36046 (14)	−0.05817 (13)	−0.09349 (10)	0.0172 (2)
H5A	1.3348	−0.0311	−0.0086	0.021*
C6	1.24650 (14)	0.03518 (12)	−0.17720 (10)	0.01485 (19)
C7	1.09255 (14)	0.17825 (13)	−0.13473 (10)	0.01589 (19)
H7A	1.0407	0.2526	−0.1957	0.019*
C8	1.02124 (15)	0.20974 (13)	−0.01471 (10)	0.0173 (2)
H8A	1.0667	0.1341	0.0477	0.021*
C9	0.87148 (14)	0.36241 (13)	0.02113 (10)	0.01643 (19)
C10	0.82784 (14)	0.40997 (13)	0.15679 (10)	0.01584 (19)
C11	0.94385 (16)	0.34122 (14)	0.24498 (11)	0.0207 (2)
H11A	1.0518	0.2604	0.2210	0.025*
C12	0.89719 (18)	0.39431 (15)	0.36938 (11)	0.0248 (2)
H12A	0.9748	0.3489	0.4284	0.030*
C13	0.73691 (17)	0.51359 (14)	0.40576 (11)	0.0218 (2)
H13A	0.7062	0.5474	0.4892	0.026*
C14	0.62110 (15)	0.58335 (13)	0.31749 (10)	0.0173 (2)
C15	0.66548 (14)	0.53249 (13)	0.19298 (10)	0.01602 (19)
H15A	0.5882	0.5793	0.1341	0.019*
C16	0.34703 (16)	0.78256 (16)	0.27587 (12)	0.0253 (2)
H16A	0.2445	0.8619	0.3194	0.038*
H16B	0.3070	0.6989	0.2355	0.038*
H16C	0.4096	0.8423	0.2137	0.038*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cl1	0.02040 (14)	0.02714 (14)	0.01654 (13)	−0.00027 (10)	−0.00537 (9)	−0.00122 (9)
O1	0.0219 (4)	0.0231 (4)	0.0173 (4)	0.0008 (3)	−0.0021 (3)	−0.0019 (3)
O2	0.0212 (4)	0.0263 (4)	0.0173 (4)	−0.0009 (3)	0.0018 (3)	−0.0059 (3)
C1	0.0140 (4)	0.0170 (4)	0.0154 (4)	−0.0045 (4)	−0.0027 (4)	−0.0004 (3)
C2	0.0166 (5)	0.0204 (5)	0.0177 (5)	−0.0041 (4)	−0.0005 (4)	−0.0049 (4)
C3	0.0155 (5)	0.0170 (4)	0.0249 (5)	−0.0014 (4)	−0.0019 (4)	−0.0049 (4)
C4	0.0168 (5)	0.0179 (5)	0.0223 (5)	−0.0030 (4)	−0.0061 (4)	−0.0004 (4)
C5	0.0162 (5)	0.0197 (5)	0.0159 (5)	−0.0044 (4)	−0.0027 (4)	−0.0019 (4)
C6	0.0129 (4)	0.0159 (4)	0.0162 (5)	−0.0043 (3)	−0.0014 (3)	−0.0022 (3)
C7	0.0137 (4)	0.0161 (4)	0.0181 (5)	−0.0038 (3)	−0.0019 (4)	−0.0023 (3)
C8	0.0173 (5)	0.0150 (4)	0.0184 (5)	−0.0029 (4)	0.0000 (4)	−0.0006 (4)
C9	0.0152 (5)	0.0162 (4)	0.0176 (5)	−0.0046 (4)	0.0005 (4)	−0.0023 (3)
C10	0.0168 (5)	0.0158 (4)	0.0154 (4)	−0.0056 (4)	−0.0005 (4)	−0.0015 (3)
C11	0.0201 (5)	0.0191 (5)	0.0218 (5)	−0.0019 (4)	−0.0042 (4)	−0.0028 (4)
C12	0.0303 (6)	0.0228 (5)	0.0204 (5)	−0.0022 (5)	−0.0100 (5)	−0.0007 (4)
C13	0.0286 (6)	0.0216 (5)	0.0151 (5)	−0.0058 (4)	−0.0025 (4)	−0.0027 (4)
C14	0.0185 (5)	0.0166 (4)	0.0168 (5)	−0.0058 (4)	0.0013 (4)	−0.0028 (4)
C15	0.0163 (5)	0.0172 (4)	0.0150 (5)	−0.0056 (4)	−0.0009 (4)	−0.0008 (3)
C16	0.0173 (5)	0.0288 (6)	0.0272 (6)	−0.0010 (4)	−0.0022 (4)	−0.0070 (5)

Geometric parameters (Å, º) top

Cl1—C1	1.7400 (11)	C8—C9	1.4836 (15)
O1—C9	1.2208 (14)	C8—H8A	0.930
O2—C14	1.3684 (13)	C9—C10	1.4952 (14)
O2—C16	1.4264 (15)	C10—C11	1.3915 (15)
C1—C2	1.3917 (14)	C10—C15	1.4028 (14)
C1—C6	1.4018 (14)	C11—C12	1.3933 (16)
C2—C3	1.3849 (16)	C11—H11A	0.930
C2—H2A	0.930	C12—C13	1.3796 (17)
C3—C4	1.3899 (16)	C12—H12A	0.930
C3—H3A	0.930	C13—C14	1.3929 (16)
C4—C5	1.3863 (15)	C13—H13A	0.930
C4—H4A	0.930	C14—C15	1.3886 (14)
C5—C6	1.4021 (15)	C15—H15A	0.930
C5—H5A	0.930	C16—H16A	0.960
C6—C7	1.4680 (14)	C16—H16B	0.960
C7—C8	1.3391 (15)	C16—H16C	0.960
C7—H7A	0.930

C14—O2—C16	117.57 (9)	O1—C9—C10	120.76 (10)
C2—C1—C6	122.55 (10)	C8—C9—C10	118.14 (9)
C2—C1—Cl1	116.93 (8)	C11—C10—C15	120.12 (10)
C6—C1—Cl1	120.49 (8)	C11—C10—C9	122.44 (10)
C3—C2—C1	119.02 (10)	C15—C10—C9	117.41 (9)
C3—C2—H2A	120.5	C10—C11—C12	119.56 (10)
C1—C2—H2A	120.5	C10—C11—H11A	120.2
C2—C3—C4	120.35 (10)	C12—C11—H11A	120.2
C2—C3—H3A	119.8	C13—C12—C11	120.58 (11)
C4—C3—H3A	119.8	C13—C12—H12A	119.7
C5—C4—C3	119.61 (10)	C11—C12—H12A	119.7
C5—C4—H4A	120.2	C12—C13—C14	119.96 (10)
C3—C4—H4A	120.2	C12—C13—H13A	120.0
C4—C5—C6	122.09 (10)	C14—C13—H13A	120.0
C4—C5—H5A	119.0	O2—C14—C15	124.45 (10)
C6—C5—H5A	119.0	O2—C14—C13	115.23 (10)
C1—C6—C5	116.37 (9)	C15—C14—C13	120.32 (10)
C1—C6—C7	122.05 (9)	C14—C15—C10	119.46 (10)
C5—C6—C7	121.56 (9)	C14—C15—H15A	120.3
C8—C7—C6	124.89 (10)	C10—C15—H15A	120.3
C8—C7—H7A	117.6	O2—C16—H16A	109.5
C6—C7—H7A	117.6	O2—C16—H16B	109.5
C7—C8—C9	121.58 (10)	H16A—C16—H16B	109.5
C7—C8—H8A	119.2	O2—C16—H16C	109.5
C9—C8—H8A	119.2	H16A—C16—H16C	109.5
O1—C9—C8	121.09 (10)	H16B—C16—H16C	109.5

C6—C1—C2—C3	1.08 (15)	O1—C9—C10—C11	−164.94 (10)
Cl1—C1—C2—C3	−176.96 (8)	C8—C9—C10—C11	14.25 (15)
C1—C2—C3—C4	0.12 (16)	O1—C9—C10—C15	13.15 (15)
C2—C3—C4—C5	−0.79 (16)	C8—C9—C10—C15	−167.66 (9)
C3—C4—C5—C6	0.30 (16)	C15—C10—C11—C12	0.30 (16)
C2—C1—C6—C5	−1.52 (15)	C9—C10—C11—C12	178.33 (10)
Cl1—C1—C6—C5	176.45 (7)	C10—C11—C12—C13	0.30 (18)
C2—C1—C6—C7	176.86 (9)	C11—C12—C13—C14	−0.69 (18)
Cl1—C1—C6—C7	−5.17 (13)	C16—O2—C14—C15	−3.86 (15)
C4—C5—C6—C1	0.82 (15)	C16—O2—C14—C13	176.68 (10)
C4—C5—C6—C7	−177.57 (10)	C12—C13—C14—O2	179.96 (10)
C1—C6—C7—C8	165.91 (10)	C12—C13—C14—C15	0.48 (17)
C5—C6—C7—C8	−15.79 (15)	O2—C14—C15—C10	−179.32 (9)
C6—C7—C8—C9	176.74 (9)	C13—C14—C15—C10	0.11 (15)
C7—C8—C9—O1	12.94 (16)	C11—C10—C15—C14	−0.50 (15)
C7—C8—C9—C10	−166.25 (9)	C9—C10—C15—C14	−178.64 (9)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2A···O2ⁱ	0.93	2.50	3.3887 (13)	161
C4—H4A···O1ⁱⁱ	0.93	2.57	3.3003 (13)	136
C16—H16B···O1ⁱⁱⁱ	0.96	2.58	3.4899 (14)	158
C16—H16C···Cg1^iv	0.96	2.82	3.6137 (14)	135

Symmetry codes: (i) x+1, y−1, z−1; (ii) x+1, y−1, z; (iii) −x+1, −y+1, −z; (iv) −x+2, −y+1, −z.

Experimental details

Crystal data
Chemical formula	C₁₆H₁₃ClO₂
M_r	272.71
Crystal system, space group	Triclinic, P1
Temperature (K)	100
a, b, c (Å)	7.7352 (2), 8.1405 (2), 10.7411 (2)
α, β, γ (°)	87.392 (1), 82.147 (1), 74.794 (1)
V (Å³)	646.52 (3)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.29
Crystal size (mm)	0.38 × 0.30 × 0.16

Data collection
Diffractometer	Bruker SMART APEXII CCD diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2005)
T_min, T_max	0.899, 0.955
No. of measured, independent and observed [I > 2σ(I)] reflections	17497, 4314, 3644
R_int	0.025
(sin θ/λ)_max (Å⁻¹)	0.739

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.037, 0.101, 1.06
No. of reflections	4314
No. of parameters	173
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.53, −0.23

Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2003).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2A···O2ⁱ	0.93	2.50	3.3887 (13)	161.1
C4—H4A···O1ⁱⁱ	0.93	2.57	3.3003 (13)	136.1
C16—H16B···O1ⁱⁱⁱ	0.96	2.58	3.4899 (14)	158.4
C16—H16C···Cg1^iv	0.96	2.82	3.6137 (14)	135

Symmetry codes: (i) x+1, y−1, z−1; (ii) x+1, y−1, z; (iii) −x+1, −y+1, −z; (iv) −x+2, −y+1, −z.

Footnotes

‡Permanent address : Department of Physics, Karunya University, Karunya Nagar, Coimbatore 641 114, India.

Acknowledgements

HKF and SRJ thank the Malaysian Government and Universiti Sains Malaysia for the Science Fund grant No. 305/PFIZIK/613312. SRJ thanks the Universiti Sains Malaysia for a postdoctoral research fellowship. This work was also supported by the Department of Science and Technology (DST), Government of India (grant No. SR/S2/LOP-17/2006).

References

Bruker (2005). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Chantrapromma, S., Jindawong, B., Fun, H.-K., Anjum, S. & Karalai, C. (2005). Acta Cryst. E61, o2096–o2098. Web of Science CSD CrossRef IUCr Journals Google Scholar
Chantrapromma, S., Ruanwas, P., Jindawong, B., Razak, I. A. & Fun, H.-K. (2006). Acta Cryst. E62, o875–o877. Web of Science CSD CrossRef IUCr Journals Google Scholar
Fun, H.-K., Rodwatcharapiban, P., Jindawong, B. & Chantrapromma, S. (2006). Acta Cryst. E62, o2725–o2727. CSD CrossRef IUCr Journals Google Scholar
Patil, P. S., Dharmaprakash, S. M., Fun, H.-K. & Karthikeyan, M. S. (2006). J. Cryst. Growth, 297, 111–116. Web of Science CrossRef CAS Google Scholar
Patil, P. S., Dharmaprakash, S. M., Ramakrishna, K., Fun, H.-K., Sai Santosh Kumar, R. & Rao, D. N. (2007). J. Cryst. Growth, 303, 520–524. Web of Science CrossRef CAS Google Scholar
Patil, P. S., Fun, H.-K., Chantrapromma, S. & Dharmaprakash, S. M. (2007). Acta Cryst. E63, o2497–o2498. 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. (2003). J. Appl. Cryst. 36, 7–13. Web of Science CrossRef CAS IUCr Journals Google Scholar