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Acta Crystallogr Sect E Struct Rep Online. 2010 July 1; 66(Pt 7): o1661.
Published online 2010 June 16. doi:  10.1107/S160053681002218X
PMCID: PMC3006708

(2E)-1-(2-Bromo­phen­yl)-3-(4-meth­oxy­phen­yl)prop-2-en-1-one

Abstract

In the title compound, C16H13BrO2, two benzene rings form a dihedral angle of 44.3 (9)°. In the crystal, weak inter­molecular C—H(...)O hydrogen bonds link the mol­ecules into chains propagating in [010]. The crystal packing also exhibits short Br(...)Br contacts of 3.4787 (8) Å. A comparison of the DFT-optimized gas-phase mol­ecular geometry with that in the crystal structure revealed only small differences.

Related literature

For the radical quenching properties of included phenol groups, see: Dhar (1981 [triangle]). For related structures, see: Arai et al. (1994 [triangle]); Li et al. (1992 [triangle]); Patil et al. (2007 [triangle]); Shettigar et al. (2006 [triangle]). For standard bond lengths, see Allen et al. (1987 [triangle]). For density functional theory, see: Schmidt & Polik (2007 [triangle]); Hehre et al. (1986 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-66-o1661-scheme1.jpg

Experimental

Crystal data

  • C16H13BrO2
  • M r = 317.17
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-66-o1661-efi1.jpg
  • a = 12.7300 (8) Å
  • b = 4.0061 (3) Å
  • c = 13.0035 (6) Å
  • β = 100.671 (5)°
  • V = 651.68 (7) Å3
  • Z = 2
  • Cu Kα radiation
  • μ = 4.25 mm−1
  • T = 110 K
  • 0.48 × 0.41 × 0.28 mm

Data collection

  • Oxford Diffraction Xcalibur diffractometer with Ruby (Gemini Cu) detector
  • Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2007 [triangle]) T min = 0.423, T max = 1.000
  • 2117 measured reflections
  • 1641 independent reflections
  • 1621 reflections with I > 2σ(I)
  • R int = 0.018

Refinement

  • R[F 2 > 2σ(F 2)] = 0.034
  • wR(F 2) = 0.091
  • S = 1.07
  • 1641 reflections
  • 173 parameters
  • 1 restraint
  • H-atom parameters constrained
  • Δρmax = 0.71 e Å−3
  • Δρmin = −0.65 e Å−3
  • Absolute structure: Flack (1983 [triangle]), 133 Friedel pairs
  • Flack parameter: 0.00 (3)

Data collection: CrysAlis PRO (Oxford Diffraction, 2007 [triangle]); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: SHELXTL (Sheldrick, 2008 [triangle]); software used to prepare material for publication: SHELXTL.

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks I. DOI: 10.1107/S160053681002218X/cv2728sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S160053681002218X/cv2728Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Acknowledgments

KV thanks the UGC for the sanction of a Junior Research Fellowship and for a SAP Chemical grant. HSY thanks the UOM for sabbatical leave. RJB acknowledges the NSF MRI program (grant No. CHE-0619278) for funds to purchase the X-ray diffractometer.

supplementary crystallographic information

Comment

Chalcones, or 1,3-diaryl-2-propen-1-ones, belong to the flavonoid family. Chemically they consist of open-chain flavonoids in which the two aromatic rings are joined by a three-carbon α,β-unsaturated carbonyl system. A vast number of naturally occurring chalcones are polyhydroxylated in the aryl rings. The radical quenching properties of the phenolic groups present in many chalcones have raised interest in using the compounds or chalcone rich plant extracts as drugs or food preservatives (Dhar, 1981). The crystal structures of some closely related chalcones, viz., 1-(4-bromophenyl)-3-(3-methoxy-phenyl)prop-2-en-1-one (Patil et al., 2007); 4-bromo-4'-methoxy-chalcone (Li et al., 1992), 4-bromo-4'-methoxychalcone (Arai et al., 1994) and 1-(4-bromophenyl)-3-(4-methoxyphenyl)prop-2-en-1-one (Shettigar et al., 2006) have been reported. Hence in continuation with the synthesis and crystal structure determination and also owing to the importance of these flavonoid analogs, this new bromo chalcone, (I), C16H13BrO2, is synthesized and its crystal structure is reported.

The title compound, (I), C16H13BrO2, is a chalcone with 4-methoxyphenyl and 2-bromophenyl rings bonded at opposite rings of a propene group (Fig. 1). The dihedral angle between mean planes of the para-methoxy and ortho-bromo substituted benzene rings is 44.3 (9)°. The angles between the mean plane of the prop-2-ene-1-one group and the mean planes of the 4-meyhoxyphenyl and 2-bromophenyl rings are 6.3 (1)° and 44.6(36°, respectively. Bond distances and angles are in normal ranges (Allen et al., 1987). While no classical hydrogen bonds are present, a weak intermolecular C12—H12A···O1 interaction (Table 1) is observed which contributes to the stability of crystal packing.

A density functional theory (DFT) geometry optimization molecular orbital calculation (Schmidt & Polik, 2007) was performed on (I) with the B3LYP 6–31-G(d) basis set (Hehre et al., 1986). The dihedral angle between mean planes of the para-methoxy and ortho-bromo substituted benzene rings becomes 45.98°, an increase of 1.59°. The angles between the mean plane of the prop-2-ene-1-one group and the mean planes of the 4-meyhoxyphenyl and 2-bromophenyl rings become 3.65° and 42.40°, changes of -2.65° and +0.74°, respectively. These observations suggest that the weak intermolecular C12—H12A···O1 interaction produces a small effect on crystal stability.

Experimental

A 50% KOH solution was added to a mixture of 2-bromo acetophenone (0.01 mol, 1.99 g) and 4-methoxy benzaldehyde (0.01 mol, 1.36 g) in 25 ml of ethanol (Fig. 2). The mixture was stirred for an hour at room temperature and the precipitate was collected by filtration and purified by recrystallization from ethanol. The single-crystal was grown from ethyl acetate by slow evaporation method and yield of the compound was 50% (m.p.336–338 K). Analytical data, composition (%): found (calculated): C: 60.52 (60.59%); H: 4.10 (4.13%).

Refinement

The H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms, with C–H distances = 0.95–0.98Å and with Uiso(H) = 1.17–1.47 Ueq(C).

Figures

Fig. 1.
Molecular structure of (I) showing the atom labeling scheme and 50% probability displacement ellipsoids.
Fig. 2.
Scheme for the synthesis of (I).

Crystal data

C16H13BrO2F(000) = 320
Mr = 317.17Dx = 1.616 Mg m3
Monoclinic, P21Cu Kα radiation, λ = 1.54184 Å
Hall symbol: P 2ybCell parameters from 1981 reflections
a = 12.7300 (8) Åθ = 4.5–74.1°
b = 4.0061 (3) ŵ = 4.25 mm1
c = 13.0035 (6) ÅT = 110 K
β = 100.671 (5)°Chunk, colourless
V = 651.68 (7) Å30.48 × 0.41 × 0.28 mm
Z = 2

Data collection

Oxford Diffraction Xcalibur diffractometer with Ruby (Gemini Cu) detector1641 independent reflections
Radiation source: Enhance (Cu) X-ray Source1621 reflections with I > 2σ(I)
graphiteRint = 0.018
Detector resolution: 10.5081 pixels mm-1θmax = 74.1°, θmin = 4.5°
ω scansh = −9→15
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2007)k = −2→4
Tmin = 0.423, Tmax = 1.000l = −15→16
2117 measured reflections

Refinement

Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.034H-atom parameters constrained
wR(F2) = 0.091w = 1/[σ2(Fo2) + (0.0718P)2 + 0.5775P] where P = (Fo2 + 2Fc2)/3
S = 1.07(Δ/σ)max = 0.001
1641 reflectionsΔρmax = 0.71 e Å3
173 parametersΔρmin = −0.65 e Å3
1 restraintAbsolute structure: Flack (1983), 133 Friedel pairs
Primary atom site location: structure-invariant direct methodsFlack parameter: 0.00 (3)

Special details

Experimental. IR data (KBr) ν cm-1: 2998 cm-1, 2937 cm-1, 2839 cm-1 (C—H al.str), 3058 cm-1 (C—H ar. str) 1646 cm-1 (C=O), 1580 cm-1 (C=C); 1245 cm-1 (C—O—C).
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)

xyzUiso*/Ueq
Br0.38764 (3)0.18817 (18)0.46303 (2)0.01538 (15)
O10.2178 (2)0.2427 (10)0.1406 (2)0.0211 (8)
O20.8860 (2)0.2977 (9)0.1659 (2)0.0209 (7)
C10.2190 (3)0.4727 (13)0.3077 (3)0.0149 (9)
C20.2577 (3)0.4233 (12)0.4142 (3)0.0119 (8)
C30.2022 (3)0.5312 (12)0.4896 (3)0.0166 (9)
H3A0.22990.49170.56160.020*
C40.1060 (3)0.6971 (19)0.4599 (3)0.0223 (8)
H4A0.06790.77400.51160.027*
C50.0651 (3)0.7513 (12)0.3545 (3)0.0211 (11)
H5A−0.00080.86600.33420.025*
C60.1203 (3)0.6385 (14)0.2797 (3)0.0187 (10)
H6A0.09130.67320.20780.022*
C70.2730 (3)0.3590 (12)0.2195 (3)0.0173 (9)
C80.3891 (3)0.4058 (13)0.2303 (3)0.0160 (9)
H8A0.42550.55260.28240.019*
C90.4441 (3)0.2431 (12)0.1673 (3)0.0161 (10)
H9A0.40370.10370.11540.019*
C100.5595 (3)0.2564 (10)0.1697 (3)0.0145 (11)
C110.5999 (3)0.1064 (11)0.0878 (3)0.0164 (10)
H11A0.5519−0.00640.03440.020*
C120.7083 (3)0.1171 (11)0.0822 (3)0.0155 (10)
H12A0.73340.01910.02480.019*
C130.7787 (3)0.2733 (11)0.1619 (3)0.0156 (10)
C140.7411 (4)0.4183 (13)0.2470 (3)0.0186 (9)
H14A0.78970.52090.30220.022*
C150.6327 (3)0.4102 (13)0.2495 (3)0.0175 (9)
H15A0.60750.51070.30650.021*
C160.9272 (3)0.1512 (18)0.0810 (3)0.0223 (11)
H16A0.9121−0.08880.07830.033*
H16B1.00460.18700.09160.033*
H16C0.89300.25530.01510.033*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
Br0.0159 (2)0.0153 (2)0.0148 (2)−0.0005 (2)0.00224 (13)0.00195 (19)
O10.0204 (13)0.028 (2)0.0151 (11)−0.0044 (15)0.0031 (10)−0.0034 (14)
O20.0169 (14)0.027 (2)0.0207 (14)−0.0012 (13)0.0070 (12)−0.0027 (13)
C10.0154 (18)0.016 (2)0.0154 (17)−0.0033 (18)0.0081 (15)−0.0001 (17)
C20.0083 (16)0.008 (2)0.0179 (17)0.0027 (16)−0.0026 (13)0.0032 (17)
C30.021 (2)0.014 (2)0.0160 (18)−0.0060 (18)0.0067 (15)−0.0023 (16)
C40.0242 (18)0.018 (2)0.0292 (19)−0.004 (3)0.0173 (15)−0.006 (3)
C50.0136 (17)0.016 (3)0.034 (2)0.0014 (18)0.0047 (16)0.0002 (19)
C60.0165 (17)0.016 (3)0.0228 (17)−0.003 (2)0.0023 (14)0.0024 (19)
C70.023 (2)0.015 (2)0.0152 (18)−0.0028 (19)0.0061 (16)0.0040 (17)
C80.0176 (19)0.015 (3)0.0155 (17)−0.0006 (18)0.0036 (14)0.0011 (17)
C90.0189 (17)0.016 (3)0.0131 (15)−0.0011 (18)0.0025 (13)0.0027 (18)
C100.0197 (18)0.014 (3)0.0113 (15)0.0016 (17)0.0058 (14)0.0018 (15)
C110.0208 (19)0.015 (3)0.0135 (16)0.0001 (17)0.0037 (14)0.0000 (15)
C120.0200 (18)0.015 (3)0.0124 (15)0.0016 (17)0.0062 (14)−0.0020 (15)
C130.0179 (18)0.014 (3)0.0159 (17)0.0019 (16)0.0068 (14)0.0034 (16)
C140.024 (2)0.019 (2)0.0122 (16)−0.001 (2)0.0024 (15)−0.0014 (18)
C150.022 (2)0.020 (3)0.0116 (16)0.002 (2)0.0071 (15)0.0001 (18)
C160.0181 (17)0.025 (3)0.0261 (18)0.000 (2)0.0101 (14)−0.004 (2)

Geometric parameters (Å, °)

Br—C21.907 (4)C8—H8A0.9500
O1—C71.224 (5)C9—C101.464 (5)
O2—C131.361 (5)C9—H9A0.9500
O2—C161.433 (5)C10—C111.401 (6)
C1—C21.396 (5)C10—C151.403 (6)
C1—C61.408 (6)C11—C121.396 (6)
C1—C71.512 (5)C11—H11A0.9500
C2—C31.380 (6)C12—C131.387 (6)
C3—C41.384 (7)C12—H12A0.9500
C3—H3A0.9500C13—C141.410 (6)
C4—C51.390 (6)C14—C151.387 (6)
C4—H4A0.9500C14—H14A0.9500
C5—C61.379 (6)C15—H15A0.9500
C5—H5A0.9500C16—H16A0.9800
C6—H6A0.9500C16—H16B0.9800
C7—C81.471 (6)C16—H16C0.9800
C8—C91.341 (6)
C13—O2—C16116.7 (3)C8—C9—H9A116.4
C2—C1—C6117.3 (4)C10—C9—H9A116.4
C2—C1—C7125.7 (4)C11—C10—C15117.6 (4)
C6—C1—C7117.1 (4)C11—C10—C9118.5 (4)
C3—C2—C1121.9 (4)C15—C10—C9123.9 (4)
C3—C2—Br116.4 (3)C12—C11—C10122.2 (4)
C1—C2—Br121.7 (3)C12—C11—H11A118.9
C2—C3—C4119.7 (4)C10—C11—H11A118.9
C2—C3—H3A120.2C13—C12—C11118.9 (4)
C4—C3—H3A120.2C13—C12—H12A120.6
C3—C4—C5120.1 (4)C11—C12—H12A120.6
C3—C4—H4A120.0O2—C13—C12124.5 (4)
C5—C4—H4A120.0O2—C13—C14115.1 (4)
C6—C5—C4119.9 (4)C12—C13—C14120.4 (4)
C6—C5—H5A120.1C15—C14—C13119.5 (4)
C4—C5—H5A120.1C15—C14—H14A120.2
C5—C6—C1121.3 (4)C13—C14—H14A120.2
C5—C6—H6A119.4C14—C15—C10121.3 (4)
C1—C6—H6A119.4C14—C15—H15A119.3
O1—C7—C8122.6 (4)C10—C15—H15A119.3
O1—C7—C1118.7 (4)O2—C16—H16A109.5
C8—C7—C1118.6 (4)O2—C16—H16B109.5
C9—C8—C7120.5 (4)H16A—C16—H16B109.5
C9—C8—H8A119.7O2—C16—H16C109.5
C7—C8—H8A119.7H16A—C16—H16C109.5
C8—C9—C10127.2 (4)H16B—C16—H16C109.5
C6—C1—C2—C30.1 (7)C1—C7—C8—C9164.4 (4)
C7—C1—C2—C3−179.0 (4)C7—C8—C9—C10−178.4 (4)
C6—C1—C2—Br177.7 (4)C8—C9—C10—C11−170.9 (4)
C7—C1—C2—Br−1.3 (7)C8—C9—C10—C159.4 (7)
C1—C2—C3—C4−0.8 (7)C15—C10—C11—C12−2.4 (6)
Br—C2—C3—C4−178.6 (4)C9—C10—C11—C12177.9 (4)
C2—C3—C4—C50.7 (8)C10—C11—C12—C131.9 (6)
C3—C4—C5—C60.2 (9)C16—O2—C13—C120.2 (7)
C4—C5—C6—C1−1.1 (8)C16—O2—C13—C14179.6 (5)
C2—C1—C6—C50.9 (7)C11—C12—C13—O2179.4 (4)
C7—C1—C6—C5180.0 (4)C11—C12—C13—C140.0 (6)
C2—C1—C7—O1139.4 (5)O2—C13—C14—C15179.2 (4)
C6—C1—C7—O1−39.6 (7)C12—C13—C14—C15−1.4 (7)
C2—C1—C7—C8−43.2 (7)C13—C14—C15—C100.8 (7)
C6—C1—C7—C8137.8 (5)C11—C10—C15—C141.0 (7)
O1—C7—C8—C9−18.2 (7)C9—C10—C15—C14−179.3 (4)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
C12—H12A···O1i0.952.593.541 (5)174

Symmetry codes: (i) −x+1, y−1/2, −z.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: CV2728).

References

  • Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19.
  • Arai, H., Higashigaki, Y., Goto, M. & Yano, S. (1994). Jpn. J. Appl. Phys.33, 5755–5758.
  • Dhar, D. N. (1981). The Chemistry of Chalcones and Related Compounds. New York: John Wiley.
  • Flack, H. D. (1983). Acta Cryst. A39, 876–881.
  • Hehre, W. J., Random, L., Schleyer, P. R. & Pople, J. A. (1986). Ab Initio Molecular Orbital Theory New York: John Wiley.
  • Li, Z.-D., Huang, L.-R., Su, G.-B. & Wang, H.-J. (1992). Jiegou Huaxue, 11, 1–4.
  • Oxford Diffraction (2007). CrysAlis PRO and CrysAlis RED Oxford Diffraction Ltd, Abingdon, England.
  • Patil, P. S., Chantrapromma, S., Fun, H.-K., Dharmaprakash, S. M. & Babu, H. B. R. (2007). Acta Cryst. E63, o2612.
  • Schmidt, J. R. & Polik, W. F. (2007). WebMO Pro WebMO, LLC, Holland, MI, USA, available from http://www.webmo.net.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Shettigar, V., Rosli, M. M., Fun, H.-K., Razak, I. A., Patil, P. S. & Dharmaprakash, S. M. (2006). Acta Cryst. E62, o4128–o4129.

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