organic compounds
(2E)-1-(2-Bromophenyl)-3-(4-methoxyphenyl)prop-2-en-1-one
aDepartment of Chemistry, Keene State College, 229 Main Street, Keene, NH 03435-2001, USA, bDepartment of Chemistry, Howard University, 525 College Street NW, Washington DC 20059, USA, cDepartment of Studies in Chemistry, Mangalore University, Mangalagangotri, 574 199, India, and dDepartment of Studies in Chemistry, University of Mysore, Manasagangotri, Mysore 570 006, India
*Correspondence e-mail: jjasinski@keene.edu
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 revealed only small differences.
Related literature
For the radical quenching properties of included phenol groups, see: Dhar (1981). For related structures, see: Arai et al. (1994); Li et al. (1992); Patil et al. (2007); Shettigar et al. (2006). For standard bond lengths, see Allen et al. (1987). For density functional theory, see: Schmidt & Polik (2007); Hehre et al. (1986).
Experimental
Crystal data
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Data collection: CrysAlis PRO (Oxford Diffraction, 2007); cell CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.
Supporting information
10.1107/S160053681002218X/cv2728sup1.cif
contains datablock I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S160053681002218X/cv2728Isup2.hkl
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%).
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).
Data collection: CrysAlis PRO (Oxford Diffraction, 2007); cell
CrysAlis PRO (Oxford Diffraction, 2007); data reduction: CrysAlis PRO (Oxford Diffraction, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).Fig. 1. Molecular structure of (I) showing the atom labeling scheme and 50% probability displacement ellipsoids. | |
Fig. 2. Scheme for the synthesis of (I). |
C16H13BrO2 | F(000) = 320 |
Mr = 317.17 | Dx = 1.616 Mg m−3 |
Monoclinic, P21 | Cu Kα radiation, λ = 1.54184 Å |
Hall symbol: P 2yb | Cell parameters from 1981 reflections |
a = 12.7300 (8) Å | θ = 4.5–74.1° |
b = 4.0061 (3) Å | µ = 4.25 mm−1 |
c = 13.0035 (6) Å | T = 110 K |
β = 100.671 (5)° | Chunk, colourless |
V = 651.68 (7) Å3 | 0.48 × 0.41 × 0.28 mm |
Z = 2 |
Oxford Diffraction Xcalibur diffractometer with Ruby (Gemini Cu) detector | 1641 independent reflections |
Radiation source: Enhance (Cu) X-ray Source | 1621 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.018 |
Detector resolution: 10.5081 pixels mm-1 | θmax = 74.1°, θmin = 4.5° |
ω scans | h = −9→15 |
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2007) | k = −2→4 |
Tmin = 0.423, Tmax = 1.000 | l = −15→16 |
2117 measured reflections |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.034 | H-atom parameters constrained |
wR(F2) = 0.091 | w = 1/[σ2(Fo2) + (0.0718P)2 + 0.5775P] where P = (Fo2 + 2Fc2)/3 |
S = 1.07 | (Δ/σ)max = 0.001 |
1641 reflections | Δρmax = 0.71 e Å−3 |
173 parameters | Δρmin = −0.65 e Å−3 |
1 restraint | Absolute structure: Flack (1983), 133 Friedel pairs |
Primary atom site location: structure-invariant direct methods | Absolute structure parameter: 0.00 (3) |
C16H13BrO2 | V = 651.68 (7) Å3 |
Mr = 317.17 | Z = 2 |
Monoclinic, P21 | Cu Kα radiation |
a = 12.7300 (8) Å | µ = 4.25 mm−1 |
b = 4.0061 (3) Å | T = 110 K |
c = 13.0035 (6) Å | 0.48 × 0.41 × 0.28 mm |
β = 100.671 (5)° |
Oxford Diffraction Xcalibur diffractometer with Ruby (Gemini Cu) detector | 1641 independent reflections |
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2007) | 1621 reflections with I > 2σ(I) |
Tmin = 0.423, Tmax = 1.000 | Rint = 0.018 |
2117 measured reflections |
R[F2 > 2σ(F2)] = 0.034 | H-atom parameters constrained |
wR(F2) = 0.091 | Δρmax = 0.71 e Å−3 |
S = 1.07 | Δρmin = −0.65 e Å−3 |
1641 reflections | Absolute structure: Flack (1983), 133 Friedel pairs |
173 parameters | Absolute structure parameter: 0.00 (3) |
1 restraint |
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. |
x | y | z | Uiso*/Ueq | ||
Br | 0.38764 (3) | 0.18817 (18) | 0.46303 (2) | 0.01538 (15) | |
O1 | 0.2178 (2) | 0.2427 (10) | 0.1406 (2) | 0.0211 (8) | |
O2 | 0.8860 (2) | 0.2977 (9) | 0.1659 (2) | 0.0209 (7) | |
C1 | 0.2190 (3) | 0.4727 (13) | 0.3077 (3) | 0.0149 (9) | |
C2 | 0.2577 (3) | 0.4233 (12) | 0.4142 (3) | 0.0119 (8) | |
C3 | 0.2022 (3) | 0.5312 (12) | 0.4896 (3) | 0.0166 (9) | |
H3A | 0.2299 | 0.4917 | 0.5616 | 0.020* | |
C4 | 0.1060 (3) | 0.6971 (19) | 0.4599 (3) | 0.0223 (8) | |
H4A | 0.0679 | 0.7740 | 0.5116 | 0.027* | |
C5 | 0.0651 (3) | 0.7513 (12) | 0.3545 (3) | 0.0211 (11) | |
H5A | −0.0008 | 0.8660 | 0.3342 | 0.025* | |
C6 | 0.1203 (3) | 0.6385 (14) | 0.2797 (3) | 0.0187 (10) | |
H6A | 0.0913 | 0.6732 | 0.2078 | 0.022* | |
C7 | 0.2730 (3) | 0.3590 (12) | 0.2195 (3) | 0.0173 (9) | |
C8 | 0.3891 (3) | 0.4058 (13) | 0.2303 (3) | 0.0160 (9) | |
H8A | 0.4255 | 0.5526 | 0.2824 | 0.019* | |
C9 | 0.4441 (3) | 0.2431 (12) | 0.1673 (3) | 0.0161 (10) | |
H9A | 0.4037 | 0.1037 | 0.1154 | 0.019* | |
C10 | 0.5595 (3) | 0.2564 (10) | 0.1697 (3) | 0.0145 (11) | |
C11 | 0.5999 (3) | 0.1064 (11) | 0.0878 (3) | 0.0164 (10) | |
H11A | 0.5519 | −0.0064 | 0.0344 | 0.020* | |
C12 | 0.7083 (3) | 0.1171 (11) | 0.0822 (3) | 0.0155 (10) | |
H12A | 0.7334 | 0.0191 | 0.0248 | 0.019* | |
C13 | 0.7787 (3) | 0.2733 (11) | 0.1619 (3) | 0.0156 (10) | |
C14 | 0.7411 (4) | 0.4183 (13) | 0.2470 (3) | 0.0186 (9) | |
H14A | 0.7897 | 0.5209 | 0.3022 | 0.022* | |
C15 | 0.6327 (3) | 0.4102 (13) | 0.2495 (3) | 0.0175 (9) | |
H15A | 0.6075 | 0.5107 | 0.3065 | 0.021* | |
C16 | 0.9272 (3) | 0.1512 (18) | 0.0810 (3) | 0.0223 (11) | |
H16A | 0.9121 | −0.0888 | 0.0783 | 0.033* | |
H16B | 1.0046 | 0.1870 | 0.0916 | 0.033* | |
H16C | 0.8930 | 0.2553 | 0.0151 | 0.033* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Br | 0.0159 (2) | 0.0153 (2) | 0.0148 (2) | −0.0005 (2) | 0.00224 (13) | 0.00195 (19) |
O1 | 0.0204 (13) | 0.028 (2) | 0.0151 (11) | −0.0044 (15) | 0.0031 (10) | −0.0034 (14) |
O2 | 0.0169 (14) | 0.027 (2) | 0.0207 (14) | −0.0012 (13) | 0.0070 (12) | −0.0027 (13) |
C1 | 0.0154 (18) | 0.016 (2) | 0.0154 (17) | −0.0033 (18) | 0.0081 (15) | −0.0001 (17) |
C2 | 0.0083 (16) | 0.008 (2) | 0.0179 (17) | 0.0027 (16) | −0.0026 (13) | 0.0032 (17) |
C3 | 0.021 (2) | 0.014 (2) | 0.0160 (18) | −0.0060 (18) | 0.0067 (15) | −0.0023 (16) |
C4 | 0.0242 (18) | 0.018 (2) | 0.0292 (19) | −0.004 (3) | 0.0173 (15) | −0.006 (3) |
C5 | 0.0136 (17) | 0.016 (3) | 0.034 (2) | 0.0014 (18) | 0.0047 (16) | 0.0002 (19) |
C6 | 0.0165 (17) | 0.016 (3) | 0.0228 (17) | −0.003 (2) | 0.0023 (14) | 0.0024 (19) |
C7 | 0.023 (2) | 0.015 (2) | 0.0152 (18) | −0.0028 (19) | 0.0061 (16) | 0.0040 (17) |
C8 | 0.0176 (19) | 0.015 (3) | 0.0155 (17) | −0.0006 (18) | 0.0036 (14) | 0.0011 (17) |
C9 | 0.0189 (17) | 0.016 (3) | 0.0131 (15) | −0.0011 (18) | 0.0025 (13) | 0.0027 (18) |
C10 | 0.0197 (18) | 0.014 (3) | 0.0113 (15) | 0.0016 (17) | 0.0058 (14) | 0.0018 (15) |
C11 | 0.0208 (19) | 0.015 (3) | 0.0135 (16) | 0.0001 (17) | 0.0037 (14) | 0.0000 (15) |
C12 | 0.0200 (18) | 0.015 (3) | 0.0124 (15) | 0.0016 (17) | 0.0062 (14) | −0.0020 (15) |
C13 | 0.0179 (18) | 0.014 (3) | 0.0159 (17) | 0.0019 (16) | 0.0068 (14) | 0.0034 (16) |
C14 | 0.024 (2) | 0.019 (2) | 0.0122 (16) | −0.001 (2) | 0.0024 (15) | −0.0014 (18) |
C15 | 0.022 (2) | 0.020 (3) | 0.0116 (16) | 0.002 (2) | 0.0071 (15) | 0.0001 (18) |
C16 | 0.0181 (17) | 0.025 (3) | 0.0261 (18) | 0.000 (2) | 0.0101 (14) | −0.004 (2) |
Br—C2 | 1.907 (4) | C8—H8A | 0.9500 |
O1—C7 | 1.224 (5) | C9—C10 | 1.464 (5) |
O2—C13 | 1.361 (5) | C9—H9A | 0.9500 |
O2—C16 | 1.433 (5) | C10—C11 | 1.401 (6) |
C1—C2 | 1.396 (5) | C10—C15 | 1.403 (6) |
C1—C6 | 1.408 (6) | C11—C12 | 1.396 (6) |
C1—C7 | 1.512 (5) | C11—H11A | 0.9500 |
C2—C3 | 1.380 (6) | C12—C13 | 1.387 (6) |
C3—C4 | 1.384 (7) | C12—H12A | 0.9500 |
C3—H3A | 0.9500 | C13—C14 | 1.410 (6) |
C4—C5 | 1.390 (6) | C14—C15 | 1.387 (6) |
C4—H4A | 0.9500 | C14—H14A | 0.9500 |
C5—C6 | 1.379 (6) | C15—H15A | 0.9500 |
C5—H5A | 0.9500 | C16—H16A | 0.9800 |
C6—H6A | 0.9500 | C16—H16B | 0.9800 |
C7—C8 | 1.471 (6) | C16—H16C | 0.9800 |
C8—C9 | 1.341 (6) | ||
C13—O2—C16 | 116.7 (3) | C8—C9—H9A | 116.4 |
C2—C1—C6 | 117.3 (4) | C10—C9—H9A | 116.4 |
C2—C1—C7 | 125.7 (4) | C11—C10—C15 | 117.6 (4) |
C6—C1—C7 | 117.1 (4) | C11—C10—C9 | 118.5 (4) |
C3—C2—C1 | 121.9 (4) | C15—C10—C9 | 123.9 (4) |
C3—C2—Br | 116.4 (3) | C12—C11—C10 | 122.2 (4) |
C1—C2—Br | 121.7 (3) | C12—C11—H11A | 118.9 |
C2—C3—C4 | 119.7 (4) | C10—C11—H11A | 118.9 |
C2—C3—H3A | 120.2 | C13—C12—C11 | 118.9 (4) |
C4—C3—H3A | 120.2 | C13—C12—H12A | 120.6 |
C3—C4—C5 | 120.1 (4) | C11—C12—H12A | 120.6 |
C3—C4—H4A | 120.0 | O2—C13—C12 | 124.5 (4) |
C5—C4—H4A | 120.0 | O2—C13—C14 | 115.1 (4) |
C6—C5—C4 | 119.9 (4) | C12—C13—C14 | 120.4 (4) |
C6—C5—H5A | 120.1 | C15—C14—C13 | 119.5 (4) |
C4—C5—H5A | 120.1 | C15—C14—H14A | 120.2 |
C5—C6—C1 | 121.3 (4) | C13—C14—H14A | 120.2 |
C5—C6—H6A | 119.4 | C14—C15—C10 | 121.3 (4) |
C1—C6—H6A | 119.4 | C14—C15—H15A | 119.3 |
O1—C7—C8 | 122.6 (4) | C10—C15—H15A | 119.3 |
O1—C7—C1 | 118.7 (4) | O2—C16—H16A | 109.5 |
C8—C7—C1 | 118.6 (4) | O2—C16—H16B | 109.5 |
C9—C8—C7 | 120.5 (4) | H16A—C16—H16B | 109.5 |
C9—C8—H8A | 119.7 | O2—C16—H16C | 109.5 |
C7—C8—H8A | 119.7 | H16A—C16—H16C | 109.5 |
C8—C9—C10 | 127.2 (4) | H16B—C16—H16C | 109.5 |
C6—C1—C2—C3 | 0.1 (7) | C1—C7—C8—C9 | 164.4 (4) |
C7—C1—C2—C3 | −179.0 (4) | C7—C8—C9—C10 | −178.4 (4) |
C6—C1—C2—Br | 177.7 (4) | C8—C9—C10—C11 | −170.9 (4) |
C7—C1—C2—Br | −1.3 (7) | C8—C9—C10—C15 | 9.4 (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—C12 | 177.9 (4) |
C2—C3—C4—C5 | 0.7 (8) | C10—C11—C12—C13 | 1.9 (6) |
C3—C4—C5—C6 | 0.2 (9) | C16—O2—C13—C12 | 0.2 (7) |
C4—C5—C6—C1 | −1.1 (8) | C16—O2—C13—C14 | 179.6 (5) |
C2—C1—C6—C5 | 0.9 (7) | C11—C12—C13—O2 | 179.4 (4) |
C7—C1—C6—C5 | 180.0 (4) | C11—C12—C13—C14 | 0.0 (6) |
C2—C1—C7—O1 | 139.4 (5) | O2—C13—C14—C15 | 179.2 (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—C10 | 0.8 (7) |
C6—C1—C7—C8 | 137.8 (5) | C11—C10—C15—C14 | 1.0 (7) |
O1—C7—C8—C9 | −18.2 (7) | C9—C10—C15—C14 | −179.3 (4) |
D—H···A | D—H | H···A | D···A | D—H···A |
C12—H12A···O1i | 0.95 | 2.59 | 3.541 (5) | 174 |
Symmetry code: (i) −x+1, y−1/2, −z. |
Experimental details
Crystal data | |
Chemical formula | C16H13BrO2 |
Mr | 317.17 |
Crystal system, space group | Monoclinic, P21 |
Temperature (K) | 110 |
a, b, c (Å) | 12.7300 (8), 4.0061 (3), 13.0035 (6) |
β (°) | 100.671 (5) |
V (Å3) | 651.68 (7) |
Z | 2 |
Radiation type | Cu Kα |
µ (mm−1) | 4.25 |
Crystal size (mm) | 0.48 × 0.41 × 0.28 |
Data collection | |
Diffractometer | Oxford Diffraction Xcalibur diffractometer with Ruby (Gemini Cu) detector |
Absorption correction | Multi-scan (CrysAlis RED; Oxford Diffraction, 2007) |
Tmin, Tmax | 0.423, 1.000 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 2117, 1641, 1621 |
Rint | 0.018 |
(sin θ/λ)max (Å−1) | 0.624 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.034, 0.091, 1.07 |
No. of reflections | 1641 |
No. of parameters | 173 |
No. of restraints | 1 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.71, −0.65 |
Absolute structure | Flack (1983), 133 Friedel pairs |
Absolute structure parameter | 0.00 (3) |
Computer programs: CrysAlis PRO (Oxford Diffraction, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
C12—H12A···O1i | 0.95 | 2.59 | 3.541 (5) | 174.3 |
Symmetry code: (i) −x+1, y−1/2, −z. |
Acknowledgements
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.
References
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This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
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.