(E)-3-(2,5-Di­fluoro­phen­yl)-1-phenyl­prop-2-en-1-one

Santos de Barros, L.; Ramalho Freitas, M.C.; Rangel Campos, V.; Assis da Silva, F.; Netto-Ferreira, J.C.; Cesarin-Sobrinho, D.

doi:10.1107/S2414314616012955

organic compounds

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ISSN: 2414-3146

Volume 1| Part 8| August 2016| x161295

doi:10.1107/S2414314616012955

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(E)-3-(2,5-Difluorophenyl)-1-phenylprop-2-en-1-one

Leonardo Santos de Barros,^a Maria Clara Ramalho Freitas,^b Vinícius Rangel Campos,^c Francisco Assis da Silva,^a José Carlos Netto-Ferreira ^d and Darí Cesarin-Sobrinho ^a ^*

^aDepartamento de Química, Instituto de Ciências Exatas, Universidade Federal Rural do Rio de Janeiro, 23851-970 Seropédica, RJ, Brazil, ^bUniversidade Federal Fluminense, Instituto de Física, Lab LDRX-UFF, 24210-346 Niterói, RJ, Brazil, ^cUniversidade Federal Fluminense, Departamento de Química Orgânica, Programa de Pós-Graduação em Química, 24020-141 Niterói, RJ, Brazil, and ^dDivisão de Metrologia Química, LAMOC, Instituto Nacional de Metrologia, Qualidade e Tecnologia, INMETRO, Av. N. Sra. das Graças, 50, 25250-020 Duque de Caxias, RJ, Brazil
^*Correspondence e-mail: cesarinsobrinho@gmail.com

Edited by H. Stoeckli-Evans, University of Neuchâtel, Switzerland (Received 29 July 2016; accepted 10 August 2016; online 16 August 2016)

The title chalcone derivative, C₁₅H₁₀F₂O, is almost planar, with the benzene ring being inclined to the phenyl ring by 7.45 (9)°. The conformation about the C=C bond is E. In the crystal, molecules are linked by two pairs of C—H⋯F hydrogen bonds, forming inversion dimers enclosing R₂²(8) and R₂¹(10) ring motifs. The dimers stack along the a axis with the separation of the C=C bonds being 4.2926 (4) Å.

Keywords: crystal structure; chalcone; [2 + 2] cycloaddition reactions; C—H⋯F hydrogen bonds; inversion dimers.

CCDC reference: 1498634

Structure description

Chalcone is a generic term given to compounds having the 1,3-diphenylprop-2-en-1-one moiety. They were the first isolatable compounds from flavonoid biosynthesis in plants (Bohm, 1998 ; Yazdan et al., 2015 ) and are widely distributed in fruits, vegetables, spices, tea and soy-based foodstuffs. They have interesting pharmacological properties (Di Carlos et al., 1999 ; Das & Manna, 2016 ), including analgesic, antioxidant, antifungal, antibacterial, antiprotozoal, gastric `protectant', antimutagenic, antitumorogenic, anti-inflammatory (Yadav et al., 2011 ) and antineurodegeneration properties (Sahu et al., 2012 ; Singh et al., 2014 ). The title chalcone derivative was obtained by a Claisen–Schimdt condensation in a basic solution of ethanol and water between 2,5-difluorobenzaldehyde and acetophenone.

The molecular structure of the title compound is illustrated in Fig. 1. The structure is almost planar, with the dihedral angle between the benzene (C1–C6) and phenyl (C10–C15) rings being 7.45 (9)°. The conformation of the keto group (C9=O1) with respect to the olefinic double bond (C7=C8) is cis. The conformation about the C7=C8 bond itself is E, with the 2,5-difluorobenzene ring opposite to the phenyl ring.

Figure 1
The molecular structure of the title compound, showing the atom labelling. Displacement ellipsoids are drawn at the 50% probability level.

In the crystal, molecules are linked by two pairs of C—H⋯F hydrogen bonds, forming inversion dimers enclosing R₂²(8) and R₂¹(10) rings (Table 1 and Fig. 2). The separation distances of bonds C7=C8⋯C7ⁱ=C8ⁱ [symmetry code: (i) 1 + x, y, z] of adjacent molecules stacked along the a axis is 4.2926 (4) Å, with an angle of 52.0 (1)° (Fig. 3). This distance is in the range for relevant distances enrolled in photochemical [2 + 2] cycloaddition reactions between olefins (Sonoda, 2011 ).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C1—H1⋯F1ⁱ	0.95	2.49	3.440 (2)	174
C11—H11⋯F1ⁱ	0.95	2.46	3.379 (2)	163
Symmetry code: (i) -x+2, -y+1, -z+1.

Figure 2
A view of the inversion dimers formed by two pairs of C—H⋯F hydrogen bonds (see Table 1

Figure 3
A view along the a axis of the crystal packing of the title compound. The C—H⋯F hydrogen bonds are shown as dashed lines (see Table 1

) and the olefin C atoms (C7 and C8) as grey balls.

Synthesis and crystallization

Potassium hydroxide in 10% molar (0.0026 g ml⁻¹) concentration relative to the ketone was added to an ethanol–water (6:1) mixture. To this solution, the total amount of 2,5-difluorobenzaldehyde (582 mg, 4.1 mmol) and half of the acetophenone (288 mg, 2.4 mmol) were added at room temperature. After approximately 1–2 h, the reminder of the acetophenone was added under constant stirring at 298 K, and the reaction was continued until the appearance of a yellow precipitate. The reaction mixture was filtered and the solid residue obtained was washed with cold water until a neutral pH was attained and was then recrystallized a number of times from a mixture of ethanol and water (yield 65%, m.p. 361–363 K). Yellow single crystals suitable for X-ray diffraction were obtained by slow evaporation of an ethanol solution of the title compound (m.p. 363 K). Spectroscopic data: IR (KBr) ν (cm⁻¹): 1674.3 (C=O s-cis); 1655.0 (C=O s-trans); 1610.9 (C=C s-cis). ¹H NMR (500 MHz, CDCl₃): δ 7.90–6.50 (m, 8H, aromatic); 7.83 (d, H₇); 7.59 (d, H₈). ¹³C NMR (125 MHz, CDCl₃): δ 198.8 (C=O); 160.5 (dd, C₂); 155.0 (dd, C₅); 137.6 (C₁₀); 135.9 (C₇); 133.0 (C₁₃); 128.6 (C₁₄=C₁₂); 128.5 (C₁₅=C₁₁); 125.3 (C₈); 118.5 (d, C₃); 117.9 (d, C₄); 117.2 (d, C₁). (MS m/z (%): 244 (M^+., 100); 243 (29); 225 (36); 215 (18); 214 (5); 201 (7); 196 (11); 195 (6); 167 (42); 139 (29); 119 (36); 105 (67); 77 (82).

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2.

Table 2
Experimental details

Crystal data
Chemical formula	C₁₅H₁₀F₂O
M_r	244.23
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	150
a, b, c (Å)	4.2926 (4), 17.7983 (13), 14.8522 (13)
β (°)	94.757 (4)
V (Å³)	1130.81 (17)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	0.11
Crystal size (mm)	0.31 × 0.23 × 0.16

Data collection
Diffractometer	Bruker D8 Venture
No. of measured, independent and observed [I > 2σ(I)] reflections	5621, 2322, 1740
R_int	0.052
(sin θ/λ)_max (Å⁻¹)	0.626

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.048, 0.136, 1.07
No. of reflections	2322
No. of parameters	163
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.32, −0.24
Computer programs: SAINT and APEX3 (Bruker, 2015 ), SHELXS97 and SHELXTL (Sheldrick, 2008 ), Mercury (Macrae et al., 2008 ), WinGX (Farrugia, 2012 ), SHELXL2014 (Sheldrick, 2015 ) and PLATON (Spek, 2009 ).

Structural data

CCDC reference: 1498634

Crystal structure: contains datablocks global, I. DOI: 10.1107/S2414314616012955/su4068sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S2414314616012955/su4068Isup2.hkl

Supporting information file. DOI: 10.1107/S2414314616012955/su4068Isup3.cml

checkCIF report

Computing details top

Data collection: SAINT (Bruker, 2015); cell refinement: APEX3 (Bruker, 2015); data reduction: SAINT (Bruker, 2015); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: SHELXTL (Sheldrick, 2008) and Mercury (Macrae et al., 2008); software used to prepare material for publication: WinGX (Farrugia, 2012), SHELXL2014 (Sheldrick, 2015) and PLATON (Spek, 2009).

(E)-3-(2,5-Difluorophenyl)-1-phenylprop-2-en-1-one top

Crystal data top

C₁₅H₁₀F₂O	F(000) = 504
M_r = 244.23	D_x = 1.435 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 3798 reflections
a = 4.2926 (4) Å	θ = 2.7–26.4°
b = 17.7983 (13) Å	µ = 0.11 mm⁻¹
c = 14.8522 (13) Å	T = 150 K
β = 94.757 (4)°	Orthombic, colorless
V = 1130.81 (17) Å³	0.31 × 0.23 × 0.16 mm
Z = 4

Data collection top

Bruker D8 Venture diffractometer	1740 reflections with I > 2σ(I)
Radiation source: Microfocus sealed tube, Incoatec Iµs	R_int = 0.052
Quazar multilayer mirror monochromator	θ_max = 26.4°, θ_min = 2.3°
φ and ω scans	h = −5→5
5621 measured reflections	k = −21→22
2322 independent reflections	l = −18→18

Refinement top

Refinement on F²	0 restraints
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.048	H-atom parameters constrained
wR(F²) = 0.136	w = 1/[σ²(F_o²) + (0.0443P)² + 0.290P] where P = (F_o² + 2F_c²)/3
S = 1.07	(Δ/σ)_max < 0.001
2322 reflections	Δρ_max = 0.32 e Å⁻³
163 parameters	Δρ_min = −0.24 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
F2	0.0822 (3)	0.50588 (6)	0.19482 (7)	0.0330 (3)
F1	0.9771 (3)	0.60432 (6)	0.44588 (7)	0.0351 (3)
O1	0.0788 (4)	0.25342 (7)	0.32124 (9)	0.0367 (4)
C1	0.6528 (4)	0.50652 (10)	0.38831 (11)	0.0229 (4)
H1	0.739	0.4748	0.4354	0.027*
C5	0.3075 (4)	0.52985 (10)	0.25802 (11)	0.0234 (4)
C6	0.4238 (4)	0.47913 (10)	0.32404 (11)	0.0215 (4)
C10	0.3791 (4)	0.21865 (10)	0.45575 (11)	0.0230 (4)
C2	0.7518 (4)	0.57955 (10)	0.38272 (12)	0.0244 (4)
C9	0.2765 (5)	0.27205 (10)	0.38094 (12)	0.0254 (4)
C3	0.6369 (5)	0.62892 (10)	0.31648 (12)	0.0267 (4)
H3	0.7128	0.679	0.3146	0.032*
C7	0.3066 (4)	0.40188 (10)	0.32591 (11)	0.0241 (4)
H7	0.1368	0.3892	0.2835	0.029*
C4	0.4083 (4)	0.60333 (10)	0.25306 (12)	0.0269 (4)
H4	0.3216	0.6357	0.2067	0.032*
C8	0.4166 (5)	0.34818 (10)	0.38147 (12)	0.0269 (4)
H8	0.5912	0.3588	0.4231	0.032*
C15	0.2643 (5)	0.14540 (11)	0.45084 (13)	0.0309 (5)
H15	0.1283	0.1304	0.4003	0.037*
C13	0.5437 (5)	0.11552 (11)	0.59271 (13)	0.0330 (5)
H13	0.601	0.0802	0.6392	0.04*
C11	0.5791 (5)	0.23899 (11)	0.53030 (12)	0.0300 (5)
H11	0.6629	0.2884	0.5342	0.036*
C14	0.3461 (5)	0.09438 (11)	0.51866 (14)	0.0360 (5)
H14	0.2666	0.0446	0.5145	0.043*
C12	0.6573 (5)	0.18811 (12)	0.59882 (13)	0.0362 (5)
H12	0.7893	0.2031	0.6502	0.043*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
F2	0.0354 (7)	0.0304 (6)	0.0309 (6)	0.0010 (5)	−0.0107 (5)	0.0019 (4)
F1	0.0362 (7)	0.0324 (6)	0.0351 (6)	−0.0080 (5)	−0.0070 (5)	0.0000 (5)
O1	0.0482 (10)	0.0251 (7)	0.0343 (7)	−0.0044 (7)	−0.0123 (7)	−0.0008 (6)
C1	0.0244 (9)	0.0224 (9)	0.0217 (9)	0.0036 (8)	0.0018 (7)	0.0033 (7)
C5	0.0218 (10)	0.0251 (9)	0.0229 (9)	0.0033 (8)	−0.0006 (7)	−0.0012 (7)
C6	0.0223 (9)	0.0198 (9)	0.0228 (9)	0.0028 (7)	0.0041 (7)	0.0003 (7)
C10	0.0247 (10)	0.0187 (9)	0.0261 (9)	0.0022 (7)	0.0050 (7)	−0.0007 (7)
C2	0.0210 (9)	0.0266 (9)	0.0253 (9)	−0.0011 (7)	0.0005 (7)	−0.0016 (7)
C9	0.0300 (10)	0.0207 (9)	0.0254 (9)	0.0012 (8)	0.0012 (8)	−0.0031 (7)
C3	0.0283 (10)	0.0210 (9)	0.0317 (10)	−0.0009 (8)	0.0079 (8)	0.0024 (7)
C7	0.0259 (10)	0.0229 (9)	0.0233 (9)	0.0013 (8)	0.0006 (7)	−0.0022 (7)
C4	0.0287 (10)	0.0243 (9)	0.0279 (9)	0.0043 (8)	0.0033 (8)	0.0078 (7)
C8	0.0279 (10)	0.0236 (9)	0.0284 (10)	−0.0007 (8)	−0.0022 (8)	0.0009 (7)
C15	0.0334 (11)	0.0238 (10)	0.0346 (10)	−0.0041 (8)	−0.0017 (8)	−0.0011 (8)
C13	0.0355 (12)	0.0285 (10)	0.0356 (11)	0.0057 (9)	0.0055 (9)	0.0113 (8)
C11	0.0387 (12)	0.0205 (9)	0.0304 (10)	−0.0025 (8)	−0.0007 (9)	0.0003 (7)
C14	0.0416 (13)	0.0214 (9)	0.0455 (12)	−0.0014 (9)	0.0059 (10)	0.0050 (8)
C12	0.0438 (13)	0.0325 (11)	0.0310 (10)	−0.0018 (10)	−0.0056 (9)	0.0037 (8)

Geometric parameters (Å, º) top

F2—C5	1.359 (2)	C3—H3	0.95
F1—C2	1.364 (2)	C7—C8	1.324 (3)
O1—C9	1.221 (2)	C7—H7	0.95
C1—C2	1.372 (2)	C4—H4	0.95
C1—C6	1.400 (2)	C8—H8	0.95
C1—H1	0.95	C15—C14	1.380 (3)
C5—C4	1.381 (3)	C15—H15	0.95
C5—C6	1.394 (2)	C13—C12	1.381 (3)
C6—C7	1.465 (2)	C13—C14	1.384 (3)
C10—C11	1.391 (3)	C13—H13	0.95
C10—C15	1.394 (3)	C11—C12	1.383 (3)
C10—C9	1.500 (2)	C11—H11	0.95
C2—C3	1.379 (3)	C14—H14	0.95
C9—C8	1.482 (3)	C12—H12	0.95
C3—C4	1.380 (3)

C2—C1—C6	119.48 (16)	C6—C7—H7	117.1
C2—C1—H1	120.3	C3—C4—C5	118.97 (16)
C6—C1—H1	120.3	C3—C4—H4	120.5
F2—C5—C4	117.93 (15)	C5—C4—H4	120.5
F2—C5—C6	118.38 (16)	C7—C8—C9	122.22 (18)
C4—C5—C6	123.69 (17)	C7—C8—H8	118.9
C5—C6—C1	116.38 (16)	C9—C8—H8	118.9
C5—C6—C7	121.15 (16)	C14—C15—C10	120.66 (18)
C1—C6—C7	122.46 (16)	C14—C15—H15	119.7
C11—C10—C15	118.51 (17)	C10—C15—H15	119.7
C11—C10—C9	123.26 (16)	C12—C13—C14	119.74 (18)
C15—C10—C9	118.23 (16)	C12—C13—H13	120.1
F1—C2—C1	118.05 (16)	C14—C13—H13	120.1
F1—C2—C3	118.42 (16)	C12—C11—C10	120.75 (18)
C1—C2—C3	123.53 (17)	C12—C11—H11	119.6
O1—C9—C8	120.61 (17)	C10—C11—H11	119.6
O1—C9—C10	120.63 (16)	C15—C14—C13	120.22 (18)
C8—C9—C10	118.75 (16)	C15—C14—H14	119.9
C2—C3—C4	117.93 (17)	C13—C14—H14	119.9
C2—C3—H3	121	C13—C12—C11	120.10 (19)
C4—C3—H3	121	C13—C12—H12	120
C8—C7—C6	125.74 (17)	C11—C12—H12	120
C8—C7—H7	117.1

F2—C5—C6—C1	−179.29 (15)	C1—C6—C7—C8	−6.1 (3)
C4—C5—C6—C1	0.7 (3)	C2—C3—C4—C5	−0.6 (3)
F2—C5—C6—C7	−0.2 (3)	F2—C5—C4—C3	−179.97 (16)
C4—C5—C6—C7	179.81 (16)	C6—C5—C4—C3	0.0 (3)
C2—C1—C6—C5	−0.8 (2)	C6—C7—C8—C9	177.78 (16)
C2—C1—C6—C7	−179.88 (16)	O1—C9—C8—C7	9.3 (3)
C6—C1—C2—F1	−179.43 (15)	C10—C9—C8—C7	−169.86 (17)
C6—C1—C2—C3	0.2 (3)	C11—C10—C15—C14	0.3 (3)
C11—C10—C9—O1	−173.28 (18)	C9—C10—C15—C14	−178.73 (19)
C15—C10—C9—O1	5.7 (3)	C15—C10—C11—C12	−1.3 (3)
C11—C10—C9—C8	5.9 (3)	C9—C10—C11—C12	177.74 (19)
C15—C10—C9—C8	−175.08 (17)	C10—C15—C14—C13	0.1 (3)
F1—C2—C3—C4	−179.81 (16)	C12—C13—C14—C15	0.4 (3)
C1—C2—C3—C4	0.6 (3)	C14—C13—C12—C11	−1.4 (3)
C5—C6—C7—C8	174.89 (18)	C10—C11—C12—C13	1.8 (3)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1···F1ⁱ	0.95	2.49	3.440 (2)	174
C11—H11···F1ⁱ	0.95	2.46	3.379 (2)	163

Symmetry code: (i) −x+2, −y+1, −z+1.

Acknowledgements

The authors gratefully acknowledge the financial support and fellowships awarded by the Brazilian funding agencies FAPERJ, CAPES and CNPq. We would also like to thank the LDRX/UFF for the use of X-ray facilities.

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