(E)-1-(4-Fluoro­phen­yl)-3-(4-methyl­phen­yl)prop-2-en-1-one

Fun, H.-K.; Jebas, S.R.; Patil, P.S.; D'Silva, E.D.; Dharmaprakash, S.M.

doi:10.1107/S1600536808011483

organic compounds

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ISSN: 2056-9890

Volume 64| Part 5| May 2008| Page o935

doi:10.1107/S1600536808011483

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(E)-1-(4-Fluorophenyl)-3-(4-methylphenyl)prop-2-en-1-one

Hoong-Kun Fun,^a ^* Samuel Robinson Jebas,^a ‡ P. S. Patil,^b E. Deepak D'Silva ^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 20 April 2008; accepted 22 April 2008; online 30 April 2008)

The title compound, C₁₆H₁₃FO, adopts an E configuration with respect to the C=C bond of the propenone unit. The dihedral angle between the two benzene rings is 47.0 (5)°. Intramolecular C—H⋯O hydrogen bonds generate an S(5) ring motif. In the crystal structure, molecules are packed into columns along the c axis and the structure is stabilized by weak intramolecular C—H⋯O hydrogen bonds and intermolecular C—H⋯π interactions involving both aromatic rings.

Related literature

For applications of chalcones in non-linear optics, see, for example, Agrinskaya et al. (1999 ); Gu et al. (2008 ); Patil et al. (2007a ,b ,c ). For related structures see: Patil et al. (2007a,b,c). For graph-set analysis of hydrogen bonding, see: Bernstein et al. (1995 ).

Experimental

Crystal data

C₁₆H₁₃FO
M_r = 240.93
Monoclinic, P 2₁ /c
a = 14.505 (2) Å
b = 14.0523 (18) Å
c = 5.8382 (8) Å
β = 92.042 (10)°
V = 1189.3 (3) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 100.0 (1) K
0.47 × 0.15 × 0.07 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ) T_min = 0.913, T_max = 0.993
14807 measured reflections
3442 independent reflections
2256 reflections with I > 2σ(I)
R_int = 0.050

Refinement

R[F² > 2σ(F²)] = 0.055
wR(F²) = 0.141
S = 1.07
3442 reflections
164 parameters
H-atom parameters constrained
Δρ_max = 0.36 e Å⁻³
Δρ_min = −0.26 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C9—H9A⋯O1	0.93	2.50	2.820 (2)	100
C5—H5A⋯Cg1ⁱ	0.93	2.96	3.525	120
C9—H9A⋯Cg1ⁱⁱ	0.93	3.02	3.604	123
C2—H2A⋯Cg2ⁱⁱⁱ	0.93	3.01	3.635	126
C14—H14A⋯Cg2^iv	0.93	2.76	3.452	132
Symmetry codes: (i) $[x, -y-{\script{1\over 2}}, z-{\script{1\over 2}}]$ ; (ii) -x+1, -y, -z+1; (iii) -x+1, -y, -z; (iv) $[x, -y-{\script{1\over 2}}, z-{\script{3\over 2}}]$ . Cg1 is the centroid of the ring C1–C6 and Cg2 is the centroid of the ring C10–C15.

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

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808011483/sj2485sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808011483/sj2485Isup2.hkl

checkCIF report

Comment top

Significant studies on applications of chalcones in nonlinear optics have motivated us to further to identify materials, especially chalcone derivatives, with appropriate absorption in the UV region along with a transmission window in the NIR range contributing to multi-photon absorption (Agrinskaya et al., 1999; Gu et al., 2008; Patil et al., 2007a-c). Here we report the crystal structure of the title chalcone derivative, (I), Fig. 1.

In (I), the molecule exhibits an E configuration with respect to the C8═C9 double bond with the C7–C8–C9–C10 torsion angle 174.6 (2)°. The bond lengths and angles in (I) are comparable to those observed in related structures (Patil et al., 2007a-c). The dihedral angle between the two benzene rings is 47.0 (2)°.

Intramolecular C—H···O hydrogen bonds generate an S(5) ring motif. In the crystal structure molecules are packed into columns along the c axis and the structure is stabilised by weak intramolecular C—H···O hydrogen bonds and intermolecular C—H···π interactions involving both aromatic rings, Table 1.

Related literature top

For applications of chalcones in non-linear optics, see, for example Agrinskaya et al. (1999); Gu et al. (2008); Patil et al. (2007a,b,c). For related structures see: Patil et al. (2007a,b,c). For graph-set analysis of hydrogen bonding, see: Bernstein et al. (1995). Cg1 is the centroid of the ring C1–C6 and Cg2 is the centroid of the ring C10–C15.

Experimental top

The compound (I) was synthesized by the condensation of p-tolualdehyde (0.01 mol) with 4-fluoroacetophenone (0.01 mol) in methanol (60 ml) in the presence of a catalytic amount of sodium hydroxide solution (5 ml, 30%). After stirring (4 h), the contents of the flask were poured into ice-cold water (500 ml) and left to stand for 5 h. The resulting crude solid was filtered and dried. The precipitated compound was recrystallized from acetone.

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: APEX2 (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 asymmetric unit of the title compound, showing 50% probability displacement ellipsoids and the atom numbering scheme. The intramolecular H-bond is drawn as a dashed line.
	Fig. 2. The crystal packing of the title compound, viewed along the a axis.

(E)-1-(4-Fluorophenyl)-3-(4-methylphenyl)prop-2-en-1-one top

Crystal data top

C₁₆H₁₃FO	F(000) = 504
M_r = 240.93	D_x = 1.342 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 1943 reflections
a = 14.505 (2) Å	θ = 2.8–34.6°
b = 14.0523 (18) Å	µ = 0.09 mm⁻¹
c = 5.8382 (8) Å	T = 100 K
β = 92.042 (10)°	Plate, colourless
V = 1189.3 (3) Å³	0.47 × 0.15 × 0.07 mm
Z = 4

Data collection top

Bruker SMART APEXII CCD area-detector diffractometer	3442 independent reflections
Radiation source: fine-focus sealed tube	2256 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.050
ϕ and ω scans	θ_max = 30.0°, θ_min = 2.0°
Absorption correction: multi-scan (SADABS; Bruker, 2005)	h = −20→16
T_min = 0.913, T_max = 0.993	k = −19→15
14807 measured reflections	l = −8→8

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)] = 0.055	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.141	H-atom parameters constrained
S = 1.07	w = 1/[σ²(F_o²) + (0.0591P)² + 0.1964P] where P = (F_o² + 2F_c²)/3
3442 reflections	(Δ/σ)_max < 0.001
164 parameters	Δρ_max = 0.36 e Å⁻³
0 restraints	Δρ_min = −0.26 e Å⁻³

Crystal data top

C₁₆H₁₃FO	V = 1189.3 (3) Å³
M_r = 240.93	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 14.505 (2) Å	µ = 0.09 mm⁻¹
b = 14.0523 (18) Å	T = 100 K
c = 5.8382 (8) Å	0.47 × 0.15 × 0.07 mm
β = 92.042 (10)°

Data collection top

Bruker SMART APEXII CCD area-detector diffractometer	3442 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2005)	2256 reflections with I > 2σ(I)
T_min = 0.913, T_max = 0.993	R_int = 0.050
14807 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.055	0 restraints
wR(F²) = 0.141	H-atom parameters constrained
S = 1.07	Δρ_max = 0.36 e Å⁻³
3442 reflections	Δρ_min = −0.26 e Å⁻³
164 parameters

Special details top

Experimental. The data was collected with the Oxford Cyrosystem Cobra low-temperature attachment.

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
F1	0.13263 (6)	0.62202 (8)	0.22333 (18)	0.0335 (3)
O1	0.52448 (8)	0.62178 (9)	−0.19348 (19)	0.0299 (3)
C1	0.37893 (11)	0.59097 (11)	0.2869 (3)	0.0223 (3)
H1A	0.4227	0.5697	0.3955	0.027*
C2	0.28643 (11)	0.58906 (11)	0.3360 (3)	0.0226 (4)
H2A	0.2671	0.5657	0.4754	0.027*
C3	0.22364 (11)	0.62262 (11)	0.1734 (3)	0.0225 (4)
C4	0.24829 (11)	0.65754 (11)	−0.0361 (3)	0.0235 (4)
H4A	0.2041	0.6804	−0.1415	0.028*
C5	0.34102 (11)	0.65749 (11)	−0.0847 (3)	0.0211 (3)
H5A	0.3594	0.6797	−0.2260	0.025*
C6	0.40712 (10)	0.62458 (11)	0.0752 (3)	0.0193 (3)
C7	0.50568 (11)	0.62320 (11)	0.0105 (3)	0.0220 (3)
C8	0.57812 (11)	0.62535 (11)	0.1937 (3)	0.0229 (3)
H8A	0.5628	0.6413	0.3423	0.027*
C9	0.66551 (11)	0.60475 (11)	0.1492 (3)	0.0203 (3)
H9A	0.6764	0.5840	0.0014	0.024*
C10	0.74563 (10)	0.61113 (10)	0.3059 (3)	0.0192 (3)
C11	0.83138 (10)	0.57998 (11)	0.2337 (3)	0.0202 (3)
H11A	0.8354	0.5513	0.0908	0.024*
C12	0.91061 (11)	0.59096 (11)	0.3709 (3)	0.0216 (3)
H12A	0.9668	0.5695	0.3189	0.026*
C13	0.90722 (11)	0.63365 (11)	0.5856 (3)	0.0211 (3)
C14	0.82142 (11)	0.66329 (11)	0.6599 (3)	0.0210 (3)
H14A	0.8176	0.6913	0.8037	0.025*
C15	0.74201 (11)	0.65200 (11)	0.5248 (3)	0.0207 (3)
H15A	0.6856	0.6717	0.5795	0.025*
C16	0.99320 (12)	0.64989 (13)	0.7314 (3)	0.0290 (4)
H16A	1.0451	0.6225	0.6577	0.044*
H16B	0.9866	0.6205	0.8784	0.044*
H16C	1.0029	0.7170	0.7512	0.044*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
F1	0.0209 (5)	0.0457 (7)	0.0340 (6)	−0.0022 (4)	0.0031 (4)	0.0022 (5)
O1	0.0265 (6)	0.0434 (8)	0.0196 (6)	0.0016 (5)	0.0013 (5)	−0.0004 (5)
C1	0.0258 (8)	0.0201 (8)	0.0207 (8)	0.0015 (6)	−0.0029 (6)	−0.0004 (6)
C2	0.0279 (8)	0.0209 (8)	0.0192 (8)	−0.0029 (6)	0.0017 (6)	0.0011 (6)
C3	0.0198 (8)	0.0213 (8)	0.0264 (9)	−0.0011 (6)	0.0016 (6)	−0.0017 (7)
C4	0.0240 (8)	0.0235 (8)	0.0226 (8)	−0.0001 (6)	−0.0044 (6)	0.0007 (7)
C5	0.0256 (8)	0.0215 (8)	0.0160 (8)	−0.0026 (6)	−0.0013 (6)	0.0001 (6)
C6	0.0216 (8)	0.0178 (8)	0.0184 (8)	0.0012 (6)	−0.0011 (6)	−0.0024 (6)
C7	0.0243 (8)	0.0213 (8)	0.0203 (8)	−0.0003 (6)	0.0006 (6)	−0.0005 (7)
C8	0.0241 (8)	0.0259 (9)	0.0185 (8)	0.0001 (6)	−0.0007 (6)	−0.0017 (7)
C9	0.0241 (8)	0.0189 (8)	0.0180 (8)	−0.0015 (6)	0.0007 (6)	0.0005 (6)
C10	0.0218 (8)	0.0171 (8)	0.0185 (8)	−0.0016 (6)	0.0005 (6)	0.0023 (6)
C11	0.0246 (8)	0.0199 (8)	0.0160 (8)	−0.0009 (6)	0.0012 (6)	−0.0002 (6)
C12	0.0204 (8)	0.0211 (8)	0.0235 (8)	0.0026 (6)	0.0017 (6)	0.0003 (6)
C13	0.0233 (8)	0.0195 (8)	0.0203 (8)	−0.0006 (6)	−0.0017 (6)	0.0020 (6)
C14	0.0274 (8)	0.0192 (8)	0.0163 (8)	0.0002 (6)	−0.0001 (6)	0.0000 (6)
C15	0.0217 (8)	0.0204 (8)	0.0202 (8)	0.0009 (6)	0.0029 (6)	0.0013 (6)
C16	0.0277 (9)	0.0317 (10)	0.0273 (9)	0.0009 (7)	−0.0041 (7)	−0.0021 (7)

Geometric parameters (Å, º) top

F1—C3	1.3621 (17)	C9—C10	1.456 (2)
O1—C7	1.2315 (18)	C9—H9A	0.9300
C1—C2	1.382 (2)	C10—C11	1.398 (2)
C1—C6	1.398 (2)	C10—C15	1.404 (2)
C1—H1A	0.9300	C11—C12	1.386 (2)
C2—C3	1.375 (2)	C11—H11A	0.9300
C2—H2A	0.9300	C12—C13	1.392 (2)
C3—C4	1.377 (2)	C12—H12A	0.9300
C4—C5	1.385 (2)	C13—C14	1.396 (2)
C4—H4A	0.9300	C13—C16	1.502 (2)
C5—C6	1.393 (2)	C14—C15	1.382 (2)
C5—H5A	0.9300	C14—H14A	0.9300
C6—C7	1.492 (2)	C15—H15A	0.9300
C7—C8	1.473 (2)	C16—H16A	0.9600
C8—C9	1.335 (2)	C16—H16B	0.9600
C8—H8A	0.9300	C16—H16C	0.9600

C2—C1—C6	120.43 (15)	C10—C9—H9A	116.3
C2—C1—H1A	119.8	C11—C10—C15	117.72 (14)
C6—C1—H1A	119.8	C11—C10—C9	119.37 (14)
C3—C2—C1	118.31 (14)	C15—C10—C9	122.83 (14)
C3—C2—H2A	120.8	C12—C11—C10	121.27 (14)
C1—C2—H2A	120.8	C12—C11—H11A	119.4
F1—C3—C2	118.24 (14)	C10—C11—H11A	119.4
F1—C3—C4	118.47 (14)	C11—C12—C13	120.90 (14)
C2—C3—C4	123.28 (15)	C11—C12—H12A	119.6
C3—C4—C5	117.83 (15)	C13—C12—H12A	119.6
C3—C4—H4A	121.1	C12—C13—C14	117.96 (15)
C5—C4—H4A	121.1	C12—C13—C16	121.36 (14)
C4—C5—C6	120.87 (14)	C14—C13—C16	120.66 (14)
C4—C5—H5A	119.6	C15—C14—C13	121.50 (15)
C6—C5—H5A	119.6	C15—C14—H14A	119.2
C5—C6—C1	119.26 (14)	C13—C14—H14A	119.2
C5—C6—C7	118.51 (13)	C14—C15—C10	120.61 (14)
C1—C6—C7	122.19 (14)	C14—C15—H15A	119.7
O1—C7—C8	121.73 (14)	C10—C15—H15A	119.7
O1—C7—C6	119.49 (15)	C13—C16—H16A	109.5
C8—C7—C6	118.77 (14)	C13—C16—H16B	109.5
C9—C8—C7	120.80 (15)	H16A—C16—H16B	109.5
C9—C8—H8A	119.6	C13—C16—H16C	109.5
C7—C8—H8A	119.6	H16A—C16—H16C	109.5
C8—C9—C10	127.36 (15)	H16B—C16—H16C	109.5
C8—C9—H9A	116.3

C6—C1—C2—C3	−1.2 (2)	C6—C7—C8—C9	166.14 (15)
C1—C2—C3—F1	−179.03 (13)	C7—C8—C9—C10	174.61 (15)
C1—C2—C3—C4	0.3 (2)	C8—C9—C10—C11	175.44 (15)
F1—C3—C4—C5	−179.85 (13)	C8—C9—C10—C15	−7.9 (3)
C2—C3—C4—C5	0.8 (3)	C15—C10—C11—C12	−1.5 (2)
C3—C4—C5—C6	−1.0 (2)	C9—C10—C11—C12	175.34 (14)
C4—C5—C6—C1	0.2 (2)	C10—C11—C12—C13	−0.1 (2)
C4—C5—C6—C7	178.00 (14)	C11—C12—C13—C14	1.2 (2)
C2—C1—C6—C5	0.9 (2)	C11—C12—C13—C16	−177.22 (15)
C2—C1—C6—C7	−176.76 (15)	C12—C13—C14—C15	−0.8 (2)
C5—C6—C7—O1	−22.4 (2)	C16—C13—C14—C15	177.69 (14)
C1—C6—C7—O1	155.31 (16)	C13—C14—C15—C10	−0.8 (2)
C5—C6—C7—C8	156.49 (15)	C11—C10—C15—C14	1.9 (2)
C1—C6—C7—C8	−25.8 (2)	C9—C10—C15—C14	−174.78 (14)
O1—C7—C8—C9	−15.0 (2)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C9—H9A···O1	0.93	2.50	2.820 (2)	100
C5—H5A···Cg1ⁱ	0.93	2.96	3.525	120
C9—H9A···Cg1ⁱⁱ	0.93	3.02	3.604	123
C2—H2A···Cg2ⁱⁱⁱ	0.93	3.01	3.635	126
C14—H14A···Cg2^iv	0.93	2.76	3.452	132

Symmetry codes: (i) x, −y−1/2, z−1/2; (ii) −x+1, −y, −z+1; (iii) −x+1, −y, −z; (iv) x, −y−1/2, z−3/2.

Experimental details

Crystal data
Chemical formula	C₁₆H₁₃FO
M_r	240.93
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	100
a, b, c (Å)	14.505 (2), 14.0523 (18), 5.8382 (8)
β (°)	92.042 (10)
V (Å³)	1189.3 (3)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.09
Crystal size (mm)	0.47 × 0.15 × 0.07

Data collection
Diffractometer	Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2005)
T_min, T_max	0.913, 0.993
No. of measured, independent and observed [I > 2σ(I)] reflections	14807, 3442, 2256
R_int	0.050
(sin θ/λ)_max (Å⁻¹)	0.703

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.055, 0.141, 1.07
No. of reflections	3442
No. of parameters	164
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.36, −0.26

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
C9—H9A···O1	0.93	2.501	2.820 (2)	100.30
C5—H5A···Cg1ⁱ	0.93	2.962	3.525	120.40
C9—H9A···Cg1ⁱⁱ	0.93	3.015	3.604	122.82
C2—H2A···Cg2ⁱⁱⁱ	0.93	3.006	3.635	126.41
C14—H14A···Cg2^iv	0.93	2.758	3.452	132.25

Symmetry codes: (i) x, −y−1/2, z−1/2; (ii) −x+1, −y, −z+1; (iii) −x+1, −y, −z; (iv) x, −y−1/2, z−3/2.

Footnotes

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

Acknowledgements

FHK 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 post-doctoral research fellowship. This work is supported by the Department of Science and Technology (DST), Government of India (Grant No.SR/S2/LOP-17/2006).

References

Agrinskaya, N. V., Lukoshkin, V. A., Kudryavtsev, V. V., Nosova, G. I., Solovskaya, N. A. & Yakimanski, A. V. (1999). Phys. Solid State, 41, 1914–1917. Web of Science CrossRef CAS Google Scholar
Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N. L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555–1573. CrossRef CAS Web of Science Google Scholar
Bruker (2005). APEX2, SAINT and SADABS . Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Gu, B., Ji, W., Patil, P. S., Dharmaprakash, S. M. & Wang, H. T. (2008). Appl. Phys. Lett. 92, 091118–091120. Web of Science CrossRef Google Scholar
Patil, P. S., Dharmaprakash, S. M., Ramakrishna, K., Fun, H.-K., Sai Santosh Kumar, R. & Rao, D. N. (2007a). J. Cryst. Growth, 303, 520–524. Web of Science CrossRef CAS Google Scholar
Patil, P. S., Fun, H.-K., Chantrapromma, S. & Dharmaprakash, S. M. (2007c). Acta Cryst. E63, o2497–o2498. Web of Science CSD CrossRef IUCr Journals Google Scholar
Patil, P. S., Rosli, M. M., Fun, H.-K., Razak, I. A. & Dharmaprakash, S. M. (2007b). Acta Cryst. E63, o3238. 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