2,3-Dibromo-3-phenyl-1-(3-phenyl­sydnon-4-yl)propan-1-one

Fun, H.-K.; Hemamalini, M.; Nithinchandra; Kalluraya, B.

doi:10.1107/S1600536811008026

organic compounds

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ISSN: 2056-9890

Volume 67| Part 4| April 2011| Page o814

doi:10.1107/S1600536811008026

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2,3-Dibromo-3-phenyl-1-(3-phenylsydnon-4-yl)propan-1-one

Hoong-Kun Fun,^a ^*‡ Madhukar Hemamalini,^a Nithinchandra ^b and Balakrishna Kalluraya ^b

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

(Received 28 February 2011; accepted 3 March 2011; online 9 March 2011)

In the title compound [systematic name: 4-(2,3-dibromo-3-phenylpropanoyl)-3-phenyl-1,2,3-oxadiazol-3-ylium-5-olate], C₁₇H₁₂Br₂N₂O₃, the oxadiazole ring is essentially planar, with a maximum deviation of 0.001 (3) Å. The central oxadiazole ring makes dihedral angles of 73.3 (2) and 29.0 (2)° with the adjacent and remote phenyl rings, respectively. In the crystal, adjacent molecules are connected by C—H⋯O hydrogen bonds, forming a supramolecular chain along the c axis. There is an intramolecular C—H⋯O hydrogen bond, which generates an S(6) ring motif.

Related literature

For applications of sydnones, see: Rai et al. (2008 ); Jyothi et al. (2008 ). For details of chalcones, see: Rai et al. (2007 ).

Experimental

Crystal data

C₁₇H₁₂Br₂N₂O₃
M_r = 452.11
Monoclinic, P 2₁ /c
a = 11.9109 (3) Å
b = 17.5018 (3) Å
c = 8.5365 (2) Å
β = 94.960 (1)°
V = 1772.87 (7) Å³
Z = 4
Mo Kα radiation
μ = 4.59 mm⁻¹
T = 296 K
0.30 × 0.20 × 0.04 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ) T_min = 0.341, T_max = 0.849
23853 measured reflections
4082 independent reflections
1912 reflections with I > 2σ(I)
R_int = 0.068

Refinement

R[F² > 2σ(F²)] = 0.043
wR(F²) = 0.104
S = 0.98
4082 reflections
217 parameters
H-atom parameters constrained
Δρ_max = 0.48 e Å⁻³
Δρ_min = −0.44 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C10—H10A⋯O2	0.98	2.35	3.028 (6)	126
C13—H13A⋯O2ⁱ	0.93	2.49	3.312 (6)	147
Symmetry code: (i) x, y, z+1.

Data collection: APEX2 (Bruker, 2009 ); cell refinement: SAINT (Bruker, 2009); 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, 2009 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536811008026/is2684sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536811008026/is2684Isup2.hkl

checkCIF report

Comment top

Sydnones constitute a well-defined class of mesoionic compounds that contain the 1,2,3-oxadiazole ring system. The study of sydnones still remains a field of interest because of their electronic structure and also because of the varied types of biological activities (Rai et al., 2008). Recently, sydnone derivatives were found to exhibit promising anti-microbial properties (Jyothi et al., 2008). Chalcones were obtained by the base-catalyzed condensation of 4-acetyl-3-aryl sydnones with aromatic aldehydes in alcoholic medium employing sodium hydroxide as catalyst at 0–5 °C. Bromination of chalcones with bromine in glacial acetic acid afforded dibromo chalcones (Rai et al., 2007).

The molecular structure of the title compound is shown in Fig. 1. The oxadiazole (N1/N2/O1/C7/C8) ring is essentially planar, with a maximum deviation of 0.001 (3) Å for atom O1. The central oxadiazole (N1/N2/O1/C7/C8) ring makes dihedral angles of 73.3 (2)° and 29.0 (2)° with the attached phenyl (C1–C6) and the terminal phenyl (C12–C17) rings, respectively.

In the crystal, (Fig. 2), the adjacent molecules are connected by intra and intermolecular C10—H10A···O2 and C13—H13A···O2 (Table 1) hydrogen bonds forming supramolecular chains along the c-axis. There is an intramolecular C—H···O hydrogen bond, which generates an S(6) ring motif.

Related literature top

For applications of sydnones, see: Rai et al. (2008); Jyothi et al. (2008). For details of chalcones, see: Rai et al. (2007).

Experimental top

1-(3¹-Phenylsydnon-4¹-yl)-3-(phenyl)-propen-1-one (0.01 mol) was dissolved in glacial acetic acid (2–30 ml) by gentle warming. A solution of bromine in glacial acetic acid (30% w/v) was added to it with constant stirring till the yellow color of the bromine persisted. The reaction mixture was stirred at room temperature for 1-2 hours. The solid which separated was filtered, washed with methanol and dried. It was then recrystallized from ethanol. Crystals suitable for X-ray analysis were obtained from 1:2 mixtures of DMF and ethanol by slow evaporation.

Computing details top

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); 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, 2009).

Figures top

	Fig. 1. The asymmetric unit of the title compound, showing 30% probability displacement ellipsoids and the atom-numbering scheme. The intramolecular hydrogen bond is shown as a dashed line.
	Fig. 2. The crystal packing of the title compound.

4-(2,3-dibromo-3-phenylpropanoyl)-3-phenyl-1,2,3-oxadiazol-3-ylium-5-olate top

Crystal data top

C₁₇H₁₂Br₂N₂O₃	F(000) = 888
M_r = 452.11	D_x = 1.694 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 3028 reflections
a = 11.9109 (3) Å	θ = 2.3–19.9°
b = 17.5018 (3) Å	µ = 4.59 mm⁻¹
c = 8.5365 (2) Å	T = 296 K
β = 94.960 (1)°	Plate, colourless
V = 1772.87 (7) Å³	0.30 × 0.20 × 0.04 mm
Z = 4

Data collection top

Bruker SMART APEXII CCD area-detector diffractometer	4082 independent reflections
Radiation source: fine-focus sealed tube	1912 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.068
ϕ and ω scans	θ_max = 27.6°, θ_min = 1.7°
Absorption correction: multi-scan (SADABS; Bruker, 2005)	h = −15→15
T_min = 0.341, T_max = 0.849	k = −22→22
23853 measured reflections	l = −11→11

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)] = 0.043	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.104	H-atom parameters constrained
S = 0.98	w = 1/[σ²(F_o²) + (0.0352P)² + 0.6409P] where P = (F_o² + 2F_c²)/3
4082 reflections	(Δ/σ)_max = 0.001
217 parameters	Δρ_max = 0.48 e Å⁻³
0 restraints	Δρ_min = −0.44 e Å⁻³

Crystal data top

C₁₇H₁₂Br₂N₂O₃	V = 1772.87 (7) Å³
M_r = 452.11	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 11.9109 (3) Å	µ = 4.59 mm⁻¹
b = 17.5018 (3) Å	T = 296 K
c = 8.5365 (2) Å	0.30 × 0.20 × 0.04 mm
β = 94.960 (1)°

Data collection top

Bruker SMART APEXII CCD area-detector diffractometer	4082 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2005)	1912 reflections with I > 2σ(I)
T_min = 0.341, T_max = 0.849	R_int = 0.068
23853 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.043	0 restraints
wR(F²) = 0.104	H-atom parameters constrained
S = 0.98	Δρ_max = 0.48 e Å⁻³
4082 reflections	Δρ_min = −0.44 e Å⁻³
217 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
Br1	0.16038 (4)	1.00790 (2)	0.96635 (6)	0.0826 (2)
Br2	0.24594 (5)	0.75050 (3)	0.96598 (7)	0.1118 (3)
O1	0.0435 (3)	0.92146 (17)	0.4180 (4)	0.0871 (9)
O2	0.2052 (3)	0.94860 (17)	0.5666 (4)	0.0889 (10)
O3	0.0007 (3)	0.8462 (2)	0.9185 (4)	0.0943 (10)
N1	−0.0551 (3)	0.87006 (17)	0.5834 (5)	0.0648 (9)
N2	−0.0581 (4)	0.8894 (2)	0.4355 (5)	0.0855 (11)
C1	−0.1583 (4)	0.7596 (2)	0.6667 (6)	0.0827 (14)
H1A	−0.0949	0.7295	0.6565	0.099*
C2	−0.2551 (4)	0.7276 (3)	0.7140 (6)	0.0939 (16)
H2A	−0.2574	0.6757	0.7365	0.113*
C3	−0.3477 (5)	0.7719 (3)	0.7279 (6)	0.0957 (16)
H3A	−0.4133	0.7502	0.7596	0.115*
C4	−0.3441 (5)	0.8483 (3)	0.6951 (7)	0.1000 (16)
H4A	−0.4076	0.8783	0.7048	0.120*
C5	−0.2478 (4)	0.8815 (3)	0.6481 (6)	0.0827 (14)
H5A	−0.2452	0.9334	0.6258	0.099*
C6	−0.1562 (4)	0.8357 (2)	0.6350 (5)	0.0639 (11)
C7	0.1121 (5)	0.9216 (2)	0.5614 (6)	0.0722 (12)
C8	0.0427 (4)	0.8868 (2)	0.6687 (5)	0.0615 (11)
C9	0.0669 (4)	0.8733 (2)	0.8348 (6)	0.0695 (12)
C10	0.1842 (4)	0.8990 (2)	0.9026 (6)	0.0768 (13)
H10A	0.2368	0.8972	0.8205	0.092*
C11	0.2311 (4)	0.8574 (3)	1.0407 (6)	0.0820 (13)
H11A	0.1767	0.8585	1.1205	0.098*
C12	0.3433 (4)	0.8850 (2)	1.1137 (6)	0.0664 (11)
C13	0.3544 (4)	0.9064 (2)	1.2683 (6)	0.0800 (13)
H13A	0.2924	0.9042	1.3273	0.096*
C14	0.4564 (6)	0.9312 (3)	1.3369 (7)	0.0982 (17)
H14A	0.4638	0.9446	1.4427	0.118*
C15	0.5474 (5)	0.9361 (3)	1.2496 (9)	0.0971 (17)
H15A	0.6165	0.9531	1.2958	0.116*
C16	0.5364 (4)	0.9164 (3)	1.0977 (8)	0.0981 (17)
H16A	0.5981	0.9207	1.0385	0.118*
C17	0.4361 (4)	0.8899 (3)	1.0275 (6)	0.0888 (14)
H17A	0.4304	0.8754	0.9223	0.107*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Br1	0.0582 (3)	0.0681 (3)	0.1219 (5)	−0.0028 (2)	0.0096 (3)	−0.0066 (3)
Br2	0.1595 (6)	0.0592 (3)	0.1144 (5)	−0.0146 (3)	−0.0012 (4)	−0.0116 (3)
O1	0.106 (3)	0.087 (2)	0.071 (2)	−0.0081 (19)	0.022 (2)	0.0099 (17)
O2	0.092 (2)	0.086 (2)	0.095 (3)	−0.0176 (18)	0.042 (2)	0.0054 (18)
O3	0.085 (2)	0.131 (3)	0.068 (2)	−0.051 (2)	0.0126 (19)	0.005 (2)
N1	0.075 (3)	0.057 (2)	0.063 (3)	−0.0025 (18)	0.008 (2)	−0.0008 (18)
N2	0.096 (3)	0.091 (3)	0.069 (3)	−0.004 (2)	0.005 (3)	0.007 (2)
C1	0.076 (3)	0.061 (3)	0.109 (4)	−0.003 (2)	−0.005 (3)	0.001 (3)
C2	0.080 (4)	0.069 (3)	0.129 (5)	−0.020 (3)	−0.011 (3)	0.010 (3)
C3	0.080 (4)	0.098 (4)	0.108 (4)	−0.023 (3)	0.003 (3)	0.007 (3)
C4	0.086 (4)	0.091 (4)	0.125 (5)	0.015 (3)	0.024 (3)	0.004 (3)
C5	0.083 (3)	0.065 (3)	0.101 (4)	0.001 (3)	0.013 (3)	0.006 (3)
C6	0.065 (3)	0.061 (3)	0.065 (3)	−0.006 (2)	0.000 (2)	0.000 (2)
C7	0.088 (4)	0.055 (3)	0.076 (4)	0.002 (2)	0.021 (3)	−0.002 (2)
C8	0.067 (3)	0.064 (2)	0.055 (3)	−0.009 (2)	0.014 (3)	0.000 (2)
C9	0.063 (3)	0.074 (3)	0.072 (4)	−0.022 (2)	0.012 (3)	−0.008 (2)
C10	0.066 (3)	0.087 (3)	0.079 (3)	−0.014 (2)	0.017 (3)	0.004 (3)
C11	0.082 (3)	0.083 (3)	0.083 (4)	−0.019 (3)	0.015 (3)	0.000 (3)
C12	0.067 (3)	0.068 (3)	0.064 (3)	−0.005 (2)	0.009 (3)	0.000 (2)
C13	0.094 (4)	0.067 (3)	0.080 (4)	−0.010 (2)	0.017 (3)	−0.011 (2)
C14	0.127 (5)	0.081 (3)	0.084 (4)	−0.012 (3)	−0.006 (4)	−0.012 (3)
C15	0.077 (4)	0.078 (3)	0.130 (6)	−0.007 (3)	−0.025 (4)	0.003 (3)
C16	0.061 (3)	0.116 (4)	0.116 (5)	0.003 (3)	0.001 (4)	0.017 (4)
C17	0.070 (3)	0.115 (4)	0.082 (4)	0.009 (3)	0.014 (3)	0.006 (3)

Geometric parameters (Å, º) top

Br1—C10	2.008 (4)	C5—H5A	0.9300
Br2—C11	1.990 (5)	C7—C8	1.422 (6)
O1—N2	1.354 (5)	C8—C9	1.442 (6)
O1—C7	1.411 (5)	C9—C10	1.533 (6)
O2—C7	1.203 (5)	C10—C11	1.455 (6)
O3—C9	1.206 (5)	C10—H10A	0.9800
N1—N2	1.304 (5)	C11—C12	1.505 (6)
N1—C8	1.351 (5)	C11—H11A	0.9800
N1—C6	1.448 (5)	C12—C13	1.367 (6)
C1—C6	1.361 (5)	C12—C17	1.382 (6)
C1—C2	1.374 (6)	C13—C14	1.372 (7)
C1—H1A	0.9300	C13—H13A	0.9300
C2—C3	1.361 (6)	C14—C15	1.370 (7)
C2—H2A	0.9300	C14—H14A	0.9300
C3—C4	1.369 (6)	C15—C16	1.338 (7)
C3—H3A	0.9300	C15—H15A	0.9300
C4—C5	1.376 (6)	C16—C17	1.370 (7)
C4—H4A	0.9300	C16—H16A	0.9300
C5—C6	1.365 (5)	C17—H17A	0.9300

N2—O1—C7	111.2 (4)	C8—C9—C10	114.9 (4)
N2—N1—C8	114.6 (4)	C11—C10—C9	115.6 (4)
N2—N1—C6	116.6 (4)	C11—C10—Br1	108.0 (3)
C8—N1—C6	128.8 (4)	C9—C10—Br1	103.6 (3)
N1—N2—O1	105.3 (4)	C11—C10—H10A	109.8
C6—C1—C2	119.2 (4)	C9—C10—H10A	109.8
C6—C1—H1A	120.4	Br1—C10—H10A	109.8
C2—C1—H1A	120.4	C10—C11—C12	116.1 (4)
C3—C2—C1	120.1 (5)	C10—C11—Br2	104.4 (3)
C3—C2—H2A	119.9	C12—C11—Br2	109.5 (3)
C1—C2—H2A	119.9	C10—C11—H11A	108.8
C2—C3—C4	119.9 (5)	C12—C11—H11A	108.8
C2—C3—H3A	120.1	Br2—C11—H11A	108.8
C4—C3—H3A	120.1	C13—C12—C17	118.8 (4)
C3—C4—C5	120.9 (5)	C13—C12—C11	119.8 (4)
C3—C4—H4A	119.5	C17—C12—C11	121.4 (4)
C5—C4—H4A	119.5	C12—C13—C14	120.4 (5)
C6—C5—C4	118.0 (4)	C12—C13—H13A	119.8
C6—C5—H5A	121.0	C14—C13—H13A	119.8
C4—C5—H5A	121.0	C15—C14—C13	120.0 (5)
C1—C6—C5	122.0 (4)	C15—C14—H14A	120.0
C1—C6—N1	119.8 (4)	C13—C14—H14A	120.0
C5—C6—N1	118.2 (4)	C16—C15—C14	119.7 (5)
O2—C7—O1	119.7 (5)	C16—C15—H15A	120.2
O2—C7—C8	136.8 (5)	C14—C15—H15A	120.2
O1—C7—C8	103.5 (4)	C15—C16—C17	121.3 (5)
N1—C8—C7	105.5 (4)	C15—C16—H16A	119.3
N1—C8—C9	125.7 (4)	C17—C16—H16A	119.3
C7—C8—C9	128.7 (4)	C16—C17—C12	119.7 (5)
O3—C9—C8	124.2 (4)	C16—C17—H17A	120.2
O3—C9—C10	120.9 (4)	C12—C17—H17A	120.2

C8—N1—N2—O1	−0.1 (5)	N1—C8—C9—O3	−1.4 (7)
C6—N1—N2—O1	178.4 (3)	C7—C8—C9—O3	176.6 (4)
C7—O1—N2—N1	0.1 (4)	N1—C8—C9—C10	−179.0 (4)
C6—C1—C2—C3	0.3 (8)	C7—C8—C9—C10	−1.1 (6)
C1—C2—C3—C4	−0.2 (8)	O3—C9—C10—C11	29.5 (6)
C2—C3—C4—C5	0.0 (8)	C8—C9—C10—C11	−152.7 (4)
C3—C4—C5—C6	0.0 (8)	O3—C9—C10—Br1	−88.4 (4)
C2—C1—C6—C5	−0.3 (7)	C8—C9—C10—Br1	89.4 (4)
C2—C1—C6—N1	−179.3 (4)	C9—C10—C11—C12	−176.7 (4)
C4—C5—C6—C1	0.1 (7)	Br1—C10—C11—C12	−61.3 (5)
C4—C5—C6—N1	179.1 (4)	C9—C10—C11—Br2	62.6 (4)
N2—N1—C6—C1	106.8 (5)	Br1—C10—C11—Br2	178.07 (17)
C8—N1—C6—C1	−74.9 (6)	C10—C11—C12—C13	123.0 (5)
N2—N1—C6—C5	−72.2 (5)	Br2—C11—C12—C13	−119.1 (4)
C8—N1—C6—C5	106.1 (5)	C10—C11—C12—C17	−56.4 (6)
N2—O1—C7—O2	−179.6 (4)	Br2—C11—C12—C17	61.6 (5)
N2—O1—C7—C8	−0.1 (4)	C17—C12—C13—C14	−1.1 (7)
N2—N1—C8—C7	0.0 (5)	C11—C12—C13—C14	179.6 (4)
C6—N1—C8—C7	−178.3 (3)	C12—C13—C14—C15	1.4 (7)
N2—N1—C8—C9	178.3 (4)	C13—C14—C15—C16	−0.3 (8)
C6—N1—C8—C9	0.1 (6)	C14—C15—C16—C17	−1.1 (8)
O2—C7—C8—N1	179.3 (5)	C15—C16—C17—C12	1.4 (8)
O1—C7—C8—N1	0.1 (4)	C13—C12—C17—C16	−0.3 (7)
O2—C7—C8—C9	1.0 (8)	C11—C12—C17—C16	179.0 (4)
O1—C7—C8—C9	−178.2 (4)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C10—H10A···O2	0.98	2.35	3.028 (6)	126
C13—H13A···O2ⁱ	0.93	2.49	3.312 (6)	147

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

Experimental details

Crystal data
Chemical formula	C₁₇H₁₂Br₂N₂O₃
M_r	452.11
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	296
a, b, c (Å)	11.9109 (3), 17.5018 (3), 8.5365 (2)
β (°)	94.960 (1)
V (Å³)	1772.87 (7)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	4.59
Crystal size (mm)	0.30 × 0.20 × 0.04

Data collection
Diffractometer	Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2005)
T_min, T_max	0.341, 0.849
No. of measured, independent and observed [I > 2σ(I)] reflections	23853, 4082, 1912
R_int	0.068
(sin θ/λ)_max (Å⁻¹)	0.652

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.043, 0.104, 0.98
No. of reflections	4082
No. of parameters	217
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.48, −0.44

Computer programs: APEX2 (Bruker, 2009), SAINT (Bruker, 2009), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C10—H10A···O2	0.9800	2.3500	3.028 (6)	126.00
C13—H13A···O2ⁱ	0.9300	2.4900	3.312 (6)	147.00

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

Footnotes

‡Thomson Reuters ResearcherID: A-3561-2009.

Acknowledgements

HKF and MH thank the Malaysian Government and Universiti Sains Malaysia for the Research University grant No. 1001/PFIZIK/811160. MH thanks Universiti Sains Malaysia for a post-doctoral research fellowship.

References

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Bruker (2009). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
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