Crystal structure of 1-[3,5-bis­(tri­fluoro­meth­yl)phen­yl]-2-bromo­ethan-1-one

Chandrashekharappa, S.; Bairagi, K.M.; Mohan, M.K.; Mohanlall, V.; Kasumbwe, K.; Venugopala, K.N.; Nayak, S.K.

doi:10.1107/S2056989018007478

research communications

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Volume 74| Part 6| June 2018| Pages 868-870

https://doi.org/10.1107/S2056989018007478

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Crystal structure of 1-[3,5-bis(trifluoromethyl)phenyl]-2-bromoethan-1-one

Sandeep Chandrashekharappa,^a Keshab M. Bairagi,^b Mahendra K. Mohan,^a Viresh Mohanlall,^c Kabange Kasumbwe,^c Katharigatta N. Venugopala ^c ^* and Susanta K. Nayak ^b ^*

^aInstitute for Stem Cell Biology and Regenerative Medicine (inStem), GKVK Campus, Bellary Road, Bangalore 560 065, Karnataka, India, ^bDepartment of Chemistry, Visvesvaraya National Institute of Technology, Nagpur 440010, Maharashtra, India, and ^cDepartment of Biotechnology and Food Technology, Faculty of Applied Science, Durban University of Technology, Durban 4001, South Africa
^*Correspondence e-mail: katharigattav@dut.ac.za, sknayak@chm.vnit.ac.in

Edited by P. Dastidar, Indian Association for the Cultivation of Science, India (Received 22 March 2018; accepted 17 May 2018; online 31 May 2018)

The title compound, C₁₀H₅BrF₆O, synthesized via continuous stirring of 3,5-bis(trifluoromethyl) acetophenone with bromine in an acidic medium and concentrated under reduced pressure, crystallizes with four molecules in the unit cell (Z = 4) and one formula unit in the asymmetric unit. In the crystal, molecules are linked in a head-to-tail fashion into dimers along the b-axis direction through weak C—H⋯Br and C—O⋯Csp² interactions. C—H⋯O, C—F⋯π and F⋯F interactions are also observed.

Keywords: crystal structure; trifluoromethyl)phenylbromoethanone; weak interactions.

CCDC reference: 1843826

1. Chemical context

Substituted phenacyl bromides can be achieved by α-bromination of substituted ketones employing suitable bromination reagents such as molecular bromine (Curran & Chang, 1989 ), copper bromide (King & Ostrum, 1964 ), N-bromosuccinimide (Tanemura et al., 2004 ), 3-methylimidazolium tribromide (Chiappe et al., 2004 ) and hydrogen bromide (Podgoršek et al., 2009 ). In our previous communications, we tried to develop intermediates (Chopra et al., 2007 ) for the construction of biologically active heterocyclic compounds (Kasumbwe et al., 2017 ). In this context, the title compound serves as a synthetic precursor and finds application in the construction of pharmacologically active heterocyclic compounds (Venugopala et al., 2018 , 2007 ).

2. Structural commentary

A displacement ellipsoid plot of the title compound with the atom labelling is shown in Fig. 1. The compound crystallizes in the monoclinic space group P2₁/c with one molecule in the asymmetric unit and four molecules in the unit cell (Z = 4). The torsion angle between the alkyl bromide unit and the phenyl ring (C3—C2—C1—Br1) is −179.6 (3)° whereas that between the alkyl bromide and carbonyl parts (O1—C2—C1—Br1) is 0.3 (5)°, which shows a preference for a syn orientation of the alkyl bromide unit with respect to the carbonyl group.

Figure 1
The asymmetric unit of the title compound, with 50% probability ellipsoids.

3. Supramolecular features

In the crystal, the molecules are arranged in a head-to-tail fashion, forming dimers sustained by C—Br⋯H and >C=O⋯π(>C=O) (O⋯π = 3.252 Å) interactions. The dimers are linked along the c-axis direction by C—H⋯O and C—F⋯π interactions (Table 1, Fig. 2). The assembly of dimers is further extended along the a-axis direction by F1⋯F4(x, $[{3\over 2}]$ − y, $[1\over2]$ + z) [2.868 (4) Å] interactions, resulting in a bilayer which further packs in parallel fashion along the a-axis direction (Fig. 3).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C1—H1A⋯O1ⁱ	0.99	2.57	3.501 (5)	157
C1—Br1⋯H4ⁱⁱ	1.92 (1)	2.94 (11)	3.882	169
C2—O1⋯C2ⁱⁱⁱ	1.20 (1)	3.05 (1)	4.126	149 (1)
C9—F2⋯π^iv	1.32 (1)	3.89	4.848	130
Symmetry codes: (i) x, y+1, z; (ii) $[-x+1, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (iii) $[-x+1, y-{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (iv) .

Figure 2
Dimer assembled through C—H⋯Br and >C=O⋯π(>C=O) interactions (left) and dimers extending along the b-axis direction via C—H⋯O and C—F⋯π interactions (Table 1

Figure 3
F⋯F interactions resulting in a bilayer that packs in a parallel fashion along the a-axis direction.

4. Database survey

There are more than 1000 crystal structure of phenyl ethanone derivatives in the Cambridge Structural Database (CSD) (Conquest Version 1.17; Groom et al., 2016 ) but none of them gave a hit for 1-[3,5-bis(trifluoromethyl)phenyl]-2-bromoethanone. However, the crystal structures of related derivatives have been reported. These include phenyl 2-bromoethanone (URELEJ; Betz et al., 2011 ) and a phenyl 2-bromoethanone complex (VIVFIP; Laube et al., 1991 ). The first compound, Z = 4, features two prominent hydrogen bonds involving the oxygen atom while in the second, also Z = 4, the oxygen atom forms a complex with antimony pentachloride.

5. Synthesis and crystallization

A stirred solution of 3,5-bis(trifluoromethyl) acetophenone (0.5 g, 1.95 mmol) in acetic acid (5 mL) was added dropwise to bromine (0.312 g, 1.95 mmol) in acetic acid. The reaction medium was stirred at room temperature for 5 h. To the resulting mixture, water (5 mL) was added and the mixture was concentrated under reduced pressure. The residue obtained was diluted with ethylacetate (10 mL), the organic layer washed with water (10 mL) and a sodium bicarbonate solution (5 mL), and filtered through dried sodium sulfate and evaporated to obtain 1-(3,5-bis(trifluoromethyl)phenyl)-2-bromoethanone as a light-yellow solid in 62% yield. m.p: 317–318 K. ¹H NMR: (CDCl₃, 600 MHz): 8.44 (2H, s), 8.13 (1H, s), 4.48 (2H, s); ¹³C NMR: (CDCl₃, 150 MHz): 188.81, 135.31, 133.06, 132.83, 132.60, 128.99, 127.08, 127.06, 125.42, 123.61, 121.80, 120.00, 29.46.

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. Hydrogen atoms were placed in idealized positions (C—H = 0.95–0.99 Å) and refined using a riding model with U_iso(H) = 1.2–1.5U_eq(C).

Table 2
Experimental details

Crystal data
Chemical formula	C₁₀H₅BrF₆O
M_r	335.04
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	153
a, b, c (Å)	14.156 (5), 5.0111 (16), 15.535 (5)
β (°)	104.316 (5)
V (Å³)	1067.7 (6)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	3.92
Crystal size (mm)	0.23 × 0.09 × 0.06

Data collection
Diffractometer	Bruker Kappa APEXII DUO
Absorption correction	Multi-scan (SADABS; Bruker, 2012 )
T_min, T_max	0.442, 0.759
No. of measured, independent and observed [I > 2σ(I)] reflections	11628, 2405, 1741
R_int	0.060
(sin θ/λ)_max (Å⁻¹)	0.646

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.041, 0.103, 1.03
No. of reflections	2405
No. of parameters	163
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.78, −1.12
Computer programs: APEX2 and SAINT (Bruker, 2012), SHELXS (Sheldrick, 2008 ), SHELXL2014 (Sheldrick, 2015 ), Mercury (Macrae et al., 2008 ), PLATON (Spek, 2009 ) and PARST (Nardelli, 1995 ).

Supporting information

CCDC reference: 1843826

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S2056989018007478/ds2250sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989018007478/ds2250Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2056989018007478/ds2250Isup3.cml

checkCIF report

Computing details top

Data collection: APEX2 (Bruker, 2012); cell refinement: SAINT (Bruker, 2012); data reduction: SAINT (Bruker, 2012); program(s) used to solve structure: SHELXS (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: PLATON (Spek, 2009) and PARST (Nardelli, 1995).

1-[3,5-Bis(trifluoromethyl)phenyl]-2-bromoethan-1-one top

Crystal data top

C₁₀H₅BrF₆O	F(000) = 648
M_r = 335.04	D_x = 2.084 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 2405 reflections
a = 14.156 (5) Å	θ = 2.7–27.4°
b = 5.0111 (16) Å	µ = 3.92 mm⁻¹
c = 15.535 (5) Å	T = 153 K
β = 104.316 (5)°	Needle, colorless
V = 1067.7 (6) Å³	0.23 × 0.09 × 0.06 mm
Z = 4

Data collection top

Bruker Kappa APEXII DUO diffractometer	2405 independent reflections
Radiation source: fine-focus sealed tube	1741 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.060
ω scans	θ_max = 27.4°, θ_min = 2.7°
Absorption correction: multi-scan (SADABS; Bruker, 2012)	h = −18→18
T_min = 0.442, T_max = 0.759	k = −6→6
11628 measured reflections	l = −20→20

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)] = 0.041	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.103	H-atom parameters constrained
S = 1.03	w = 1/[σ²(F_o²) + (0.0541P)² + 0.3605P] where P = (F_o² + 2F_c²)/3
2405 reflections	(Δ/σ)_max < 0.001
163 parameters	Δρ_max = 0.78 e Å⁻³
0 restraints	Δρ_min = −1.12 e Å⁻³

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Br1	0.60416 (2)	0.14882 (9)	0.09433 (3)	0.03259 (16)
F1	0.21893 (17)	0.1990 (6)	0.38145 (15)	0.0468 (7)
F2	0.1420 (2)	−0.0983 (6)	0.29661 (17)	0.0597 (8)
F3	0.07527 (19)	0.2781 (7)	0.3050 (2)	0.0655 (9)
F4	0.19332 (17)	0.8957 (5)	0.00403 (18)	0.0480 (7)
F5	0.07651 (19)	0.8912 (5)	0.06942 (16)	0.0484 (7)
F6	0.07736 (15)	0.6137 (5)	−0.03417 (14)	0.0362 (6)
O1	0.45527 (18)	−0.0571 (6)	0.18612 (18)	0.0329 (6)
C1	0.4825 (2)	0.3126 (8)	0.0979 (3)	0.0278 (9)
H1A	0.4955	0.4921	0.1249	0.033*
H1B	0.4423	0.3352	0.0365	0.033*
C2	0.4258 (3)	0.1506 (8)	0.1506 (2)	0.0258 (8)
C3	0.3301 (2)	0.2646 (8)	0.1557 (2)	0.0237 (8)
C4	0.2889 (3)	0.1673 (8)	0.2217 (2)	0.0264 (8)
H4	0.3218	0.0353	0.2620	0.032*
C5	0.1991 (2)	0.2642 (8)	0.2285 (2)	0.0255 (8)
C6	0.1483 (2)	0.4474 (8)	0.1686 (2)	0.0259 (8)
H6	0.0857	0.5070	0.1722	0.031*
C7	0.1901 (2)	0.5434 (8)	0.1028 (2)	0.0239 (8)
C8	0.2806 (3)	0.4557 (8)	0.0968 (2)	0.0255 (8)
H8	0.3091	0.5261	0.0524	0.031*
C9	0.1583 (3)	0.1609 (9)	0.3022 (3)	0.0313 (9)
C10	0.1348 (3)	0.7374 (9)	0.0362 (3)	0.0308 (9)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Br1	0.0200 (2)	0.0386 (3)	0.0398 (3)	0.00282 (17)	0.00868 (15)	−0.0043 (2)
F1	0.0405 (14)	0.072 (2)	0.0306 (13)	−0.0144 (13)	0.0130 (11)	−0.0053 (12)
F2	0.093 (2)	0.044 (2)	0.0531 (17)	−0.0302 (15)	0.0394 (16)	−0.0108 (13)
F3	0.0370 (14)	0.094 (2)	0.077 (2)	0.0245 (15)	0.0356 (14)	0.0359 (17)
F4	0.0332 (13)	0.0366 (17)	0.0686 (18)	−0.0044 (11)	0.0020 (12)	0.0237 (13)
F5	0.0500 (14)	0.0464 (18)	0.0440 (14)	0.0282 (13)	0.0024 (11)	−0.0025 (12)
F6	0.0292 (11)	0.0432 (17)	0.0324 (12)	−0.0001 (10)	0.0005 (9)	−0.0029 (10)
O1	0.0285 (14)	0.0294 (18)	0.0420 (16)	0.0055 (12)	0.0109 (12)	0.0065 (13)
C1	0.0188 (16)	0.029 (3)	0.036 (2)	0.0010 (15)	0.0074 (15)	−0.0008 (17)
C2	0.0235 (17)	0.023 (2)	0.030 (2)	−0.0036 (16)	0.0046 (14)	−0.0040 (17)
C3	0.0203 (17)	0.023 (2)	0.028 (2)	−0.0016 (15)	0.0056 (15)	−0.0021 (16)
C4	0.0237 (17)	0.022 (2)	0.032 (2)	−0.0005 (15)	0.0052 (15)	−0.0020 (16)
C5	0.0230 (18)	0.025 (2)	0.028 (2)	−0.0036 (15)	0.0061 (15)	−0.0023 (16)
C6	0.0189 (16)	0.025 (2)	0.034 (2)	0.0007 (15)	0.0056 (15)	−0.0002 (17)
C7	0.0190 (16)	0.021 (2)	0.029 (2)	0.0009 (14)	0.0017 (14)	−0.0010 (16)
C8	0.0274 (18)	0.021 (2)	0.028 (2)	−0.0007 (15)	0.0071 (15)	−0.0012 (16)
C9	0.0253 (18)	0.032 (3)	0.037 (2)	−0.0022 (17)	0.0085 (16)	−0.0016 (18)
C10	0.0263 (19)	0.029 (2)	0.034 (2)	0.0032 (17)	0.0013 (16)	−0.0008 (18)

Geometric parameters (Å, º) top

Br1—C1	1.921 (4)	C3—C4	1.388 (5)
F1—C9	1.329 (4)	C3—C8	1.389 (5)
F2—C9	1.319 (5)	C4—C5	1.388 (5)
F3—C9	1.325 (4)	C4—H4	0.9500
F4—C10	1.330 (5)	C5—C6	1.377 (5)
F5—C10	1.324 (5)	C5—C9	1.497 (5)
F6—C10	1.343 (4)	C6—C7	1.388 (5)
O1—C2	1.203 (5)	C6—H6	0.9500
C1—C2	1.516 (5)	C7—C8	1.378 (5)
C1—H1A	0.9900	C7—C10	1.492 (5)
C1—H1B	0.9900	C8—H8	0.9500
C2—C3	1.490 (5)

C2—C1—Br1	112.7 (3)	C7—C6—H6	120.6
C2—C1—H1A	109.1	C8—C7—C6	120.8 (3)
Br1—C1—H1A	109.1	C8—C7—C10	119.9 (3)
C2—C1—H1B	109.1	C6—C7—C10	119.3 (3)
Br1—C1—H1B	109.1	C7—C8—C3	120.1 (3)
H1A—C1—H1B	107.8	C7—C8—H8	119.9
O1—C2—C3	121.6 (3)	C3—C8—H8	119.9
O1—C2—C1	122.7 (3)	F2—C9—F3	107.2 (3)
C3—C2—C1	115.7 (3)	F2—C9—F1	105.4 (3)
C4—C3—C8	119.5 (3)	F3—C9—F1	106.3 (3)
C4—C3—C2	117.3 (3)	F2—C9—C5	112.7 (3)
C8—C3—C2	123.1 (3)	F3—C9—C5	112.7 (3)
C5—C4—C3	119.5 (4)	F1—C9—C5	112.1 (3)
C5—C4—H4	120.2	F5—C10—F4	107.8 (4)
C3—C4—H4	120.2	F5—C10—F6	106.0 (3)
C6—C5—C4	121.2 (3)	F4—C10—F6	106.1 (3)
C6—C5—C9	120.8 (3)	F5—C10—C7	112.4 (3)
C4—C5—C9	118.0 (4)	F4—C10—C7	112.4 (3)
C5—C6—C7	118.8 (3)	F6—C10—C7	111.8 (3)
C5—C6—H6	120.6

Br1—C1—C2—O1	0.3 (5)	C10—C7—C8—C3	−176.6 (4)
Br1—C1—C2—C3	−179.6 (3)	C4—C3—C8—C7	−1.4 (6)
O1—C2—C3—C4	17.6 (5)	C2—C3—C8—C7	176.9 (3)
C1—C2—C3—C4	−162.5 (3)	C6—C5—C9—F2	117.1 (4)
O1—C2—C3—C8	−160.8 (4)	C4—C5—C9—F2	−62.1 (5)
C1—C2—C3—C8	19.1 (5)	C6—C5—C9—F3	−4.4 (6)
C8—C3—C4—C5	−0.6 (6)	C4—C5—C9—F3	176.5 (4)
C2—C3—C4—C5	−179.0 (3)	C6—C5—C9—F1	−124.2 (4)
C3—C4—C5—C6	2.7 (6)	C4—C5—C9—F1	56.6 (5)
C3—C4—C5—C9	−178.1 (3)	C8—C7—C10—F5	−151.0 (4)
C4—C5—C6—C7	−2.7 (6)	C6—C7—C10—F5	30.9 (5)
C9—C5—C6—C7	178.2 (3)	C8—C7—C10—F4	−29.3 (5)
C5—C6—C7—C8	0.5 (6)	C6—C7—C10—F4	152.6 (4)
C5—C6—C7—C10	178.7 (4)	C8—C7—C10—F6	89.9 (4)
C6—C7—C8—C3	1.5 (6)	C6—C7—C10—F6	−88.2 (4)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1A···O1ⁱ	0.99	2.57	3.501 (5)	157
C1—Br1···H4ⁱⁱ	1.92 (1)	2.94 (11)	3.882	169
C2—O1···C2ⁱⁱⁱ	1.20 (1)	3.05 (1)	4.126	149 (1)
C9—F2···π^iv	1.32 (1)	3.89	4.848	130

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

Funding information

The authors are thankful to the National Research Foundation (96807 and 98884), South Africa and Durban University of Technology, South Africa, for support and encouragement. KMB thanks VNIT Nagpur for the support of a research fellowship.

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