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

Jerry P Jasinski; Ray J Butcher; K Veena; B Narayana; H S Yathirajan

doi:10.1107/S160053681002218X

. 2010 Jun 16;66(Pt 7):o1661. doi: 10.1107/S160053681002218X

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

Jerry P Jasinski ^a,^*, Ray J Butcher ^b, K Veena ^c, B Narayana ^c, H S Yathirajan ^d

PMCID: PMC3006708 PMID: 21587888

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 ▶). 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

C₁₆H₁₃BrO₂
M _r = 317.17
Monoclinic,
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 ▶) 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
Δρ_max = 0.71 e Å⁻³
Δρ_min = −0.65 e Å⁻³
Absolute structure: Flack (1983 ▶), 133 Friedel pairs
Flack parameter: 0.00 (3)

Data collection: CrysAlis PRO (Oxford Diffraction, 2007 ▶); cell refinement: 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.

Supplementary Material

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

e-66-o1661-sup1.cif^{(17.6KB, cif)}

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

e-66-o1661-Isup2.hkl^{(80.8KB, hkl)}

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C12—H12A⋯O1ⁱ	0.95	2.59	3.541 (5)	174

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Symmetry code: (i) Inline graphic .

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%).