2,3-Dibromo-3-(5-bromo-2-methoxy­phen­yl)-1-(2,4-dichloro­phen­yl)propan-1-one

In the title mol­ecule, C₁₆H₁₁Br₃Cl₂O₂, the chain Br atoms are in trans positions [Br—C—C—Br torsion angle is 179.0 (2)°]. The two benzene rings make a dihedral angle of 39.54 (15)°. The crystal packing is determined by van der Waals forces; some weak π–π inter­actions between the benzene rings of neighbouring mol­ecules are also possible [the distance between their centroids is 3.753 (5) Å]. Intermolecular C—H...Br interactions are also present.

Key indicators

• Single-crystal X-ray study
• T = 295 K
• Mean [sigma](C-C) = 0.007 Å
• R factor = 0.037
• wR factor = 0.099
• Data-to-parameter ratio = 14.9

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT341_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ...          7
PLAT431_ALERT_2_C Short Inter HL..A Contact  Br2    ..  Cl12    ..       3.59 Ang.
PLAT480_ALERT_4_C Long H...A H-Bond Reported H32    ..  BR33    ..       3.10 Ang.
PLAT480_ALERT_4_C Long H...A H-Bond Reported H36A   ..  BR3     ..       3.03 Ang.
PLAT480_ALERT_4_C Long H...A H-Bond Reported H36B   ..  BR2     ..       3.00 Ang.

Alert level G
PLAT793_ALERT_1_G Check the Absolute Configuration of C2     = ...          S
PLAT793_ALERT_1_G Check the Absolute Configuration of C3     = ...          R

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   5 ALERT level C = Check and explain
   2 ALERT level G = General alerts; check

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   3 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

For a structurally simple group of compounds, chalcones display an impressive array of biological activities, among which antimalarial (Liu et al., 2003), antiprotozoal (Nielsen et al., 1998), nitric oxide inhibition (Rojas et al., 2002) and anticancer activities have been reported in the literature. Among several organic compounds reported for non-linear optical (NLO) properties, chalcone derivatives are notable materials for their excellent blue light transmittance and good crystallizability (Indira et al., 2002; Sarojini et al., 2006). They provide a necessary configuration to show NLO properties, with two planar rings connected through a conjugated double bond. The substitution of a bromo group on either of the phenyl rings greatly influences the non-centrosymmetric crystal packing. The bromo group can obviously improve the molecular first-order hyperpolarizabilities and can effectively reduce dipole - dipole interactions between the molecules. Chalcone derivatives usually have a lower melting temperature, which can be a drawback when we use these crystals in optical instruments, but chalcone dibromides usually have higher melting points and are thermally stable. A new chalcone dibromide (1), C₁₆H₁₂Br₂Cl₂O₂, was prepared by the bromination of the chalcone, (2E)-1-(2,4-Dichlorophenyl)-3-(2-methoxyphenyl)prop-2-en-1-one. During the bromination process the excess bromine reacted with the dibromide to form 2,3-dibromo-3-(5-bromo-2-methoxyphenyl)-1-(2,4-dichlorophenyl) propan-1-one (1). Due to the space group symmetry, the racemic mixture is present in the crystal structure.

The conformation of 1 (Fig. 1) can be described by the torsion angles between two approximately planar benzene rings with maximum deviations from mean planes of 0.009 (3) Å and 0.019 (3) Å for the rings C11 - C16 (A) and C31 - C36 (B), respectively, and the central C1—C2—C3 bridge (C). The values of these angles: A/B 39.54 (15)°, A/C 56.8 (3)°, and B/C 44.4 (3)° show that the rings are twisted in opposite sense with respect to the central bridge. The bromine Br2 and Br3 atoms are in mutual trans position, the torsion angle Br2—C2—C3—Br3 is 179.0 (2)°. The C—Br distances for C(sp³) and C(sp²) carbon atoms are significantly different: 2.007 (5) Å and 2.018 (5) Å for the former and 1.898 (5) Å for the latter.

In the crystal structure, besides the van der Waals forces (Fig. 2) there are also some C···C short contacts between neighbouring benzene rings: C14···C14(1 - x,-y,1 - z) of 3.429 (3) Å and C34···C36(-x,-y,-z) of 3.349 (3) Å. Only in the latter case, however, there is an overlap between the rings with the short distance of 3.753 (5) Å between their centroids, thus only in this case some π-π interaction is possible. Additionally, some directional weak C—H···Br interactions (Table 1) can be important. Short contact Cl12···Br2(x,1 + y,z) of 3.590 (5) Å is observed within the chains of molecules along [010] direction.

Related literature

For related structures, see: Yathirajan et al. (2007a,b); Butcher et al. (2006a,b,c); Harrison et al. (2005). Various biological activities of chalcones were reported e.g. by Nielsen et al. (1998); Rojas et al. (2002) and Liu et al. (2003). For non-linear optical (NLO) properties of chalcone derivatives, see, for example, Indira et al. (2002) and Sarojini et al. (2006).

S2. Experimental

(2E)-1-(2,4-Dichlorophenyl)-3-(2-methoxyphenyl)prop-2-en-1-one (3.07 g, 0.01 mol) was treated with bromine in acetic acid (30%) until the orange colour of the solution persisted. After stirring for half an hour, the content was poured on to crushed ice. The resulting solid mass was collected by filtration. The compound was dried and recrystallized from ethanol. Crystals suitable for structure determination were obtained from ethyl acetate by slow evaporation (yield 70%; m.p. 385–388 K). Analysis for C₁₆H₁₁Br₃Cl₂O₂ found (calculated): C: 35.12 (35.20), H: 1.99% (2.03%).

S3. Refinement

The hydrogen atoms were placed in the idealized positions (C—H 0.93–0.98 Å) and refined using a riding model approximation, with U_iso(H)=1.2 or 1.3 U_eq(C).

Computing details

Data collection: CrysAlis CCD (Oxford Diffraction, 2006); cell refinement: CrysAlis RED (Oxford Diffraction, 2006); data reduction: CrysAlis RED (Oxford Diffraction, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP (Siemens, 1989); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures

	Fig. 1. The molecular structure of 1 showing the atomic numbering and displacement ellipsoids drawn at the 50% probability level.
	Fig. 2. A portion of the crystal packing as seen approximately along direction [010].

2,3-Dibromo-3-(5-bromo-2-methoxyphenyl)-1-(2,4-dichlorophenyl)propan-1-one

Crystal data

C16H11Br3Cl2O2	F(000) = 1048
Mr = 545.88	Dx = 2.015 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 7661 reflections
a = 15.9189 (8) Å	θ = 4–24°
b = 7.3729 (3) Å	µ = 7.03 mm^−1
c = 15.4895 (7) Å	T = 295 K
β = 98.125 (4)°	Plate, colourless
V = 1799.73 (14) Å^3	0.4 × 0.2 × 0.1 mm
Z = 4

Data collection

Kuma KM-4-CCD four-circle diffractometer	3104 independent reflections
Radiation source: fine-focus sealed tube	2223 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.034
Detector resolution: 8.1929 pixels mm^-1	θmax = 25.0°, θmin = 2.6°
ω scans	h = −18→18
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2006)	k = −8→8
Tmin = 0.12, Tmax = 0.495	l = −18→18
17972 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.037	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.099	H-atom parameters constrained
S = 1.20	w = 1/[σ^2(Fo^2) + (0.05P)^2] where P = (Fo^2 + 2Fc^2)/3
3104 reflections	(Δ/σ)max < 0.001
209 parameters	Δρmax = 0.70 e Å^−3
0 restraints	Δρmin = −0.62 e Å^−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
C1	0.3657 (3)	0.0862 (6)	0.2091 (3)	0.0477 (11)
O1	0.3990 (2)	0.0840 (5)	0.1434 (2)	0.0666 (10)
C11	0.4172 (3)	0.1263 (6)	0.2947 (3)	0.0414 (10)
C12	0.3936 (3)	0.2306 (6)	0.3619 (3)	0.0432 (11)
Cl12	0.29453 (8)	0.33676 (17)	0.35285 (9)	0.0624 (4)
C13	0.4480 (3)	0.2662 (6)	0.4375 (3)	0.0492 (11)
H13	0.4311	0.3387	0.4811	0.059*
C14	0.5279 (3)	0.1913 (6)	0.4466 (3)	0.0524 (12)
Cl14	0.59819 (10)	0.2366 (2)	0.54041 (10)	0.0784 (5)
C15	0.5540 (3)	0.0844 (7)	0.3831 (3)	0.0589 (13)
H15	0.6080	0.0335	0.3908	0.071*
C16	0.4987 (3)	0.0538 (7)	0.3077 (3)	0.0547 (12)
H16	0.5164	−0.0176	0.2642	0.066*
C2	0.2743 (3)	0.0217 (6)	0.2043 (3)	0.0508 (12)
H2	0.2455	0.0871	0.2468	0.061*
Br2	0.28480 (3)	−0.24233 (7)	0.23529 (4)	0.06278 (19)
C3	0.2234 (3)	0.0314 (7)	0.1163 (3)	0.0578 (13)
H3	0.2552	−0.0256	0.0737	0.069*
Br3	0.21543 (4)	0.30078 (7)	0.09355 (4)	0.0685 (2)
C31	0.1356 (3)	−0.0502 (6)	0.1079 (3)	0.0506 (12)
C32	0.0821 (3)	−0.0102 (6)	0.1681 (3)	0.0510 (12)
H32	0.1003	0.0653	0.2151	0.061*
C33	0.0011 (3)	−0.0831 (6)	0.1581 (3)	0.0520 (12)
Br33	−0.07145 (3)	−0.03042 (8)	0.24203 (4)	0.0726 (2)
C34	−0.0275 (3)	−0.1906 (6)	0.0881 (4)	0.0588 (13)
H34	−0.0830	−0.2333	0.0802	0.071*
C35	0.0263 (4)	−0.2350 (6)	0.0297 (4)	0.0634 (14)
H35	0.0078	−0.3117	−0.0168	0.076*
C36	0.1081 (3)	−0.1660 (6)	0.0397 (3)	0.0557 (13)
O36	0.1652 (3)	−0.2010 (6)	−0.0165 (2)	0.0818 (12)
C361	0.1462 (4)	−0.3400 (8)	−0.0815 (4)	0.086 (2)
H36A	0.1380	−0.4535	−0.0535	0.112*
H36B	0.1925	−0.3508	−0.1147	0.112*
H36C	0.0954	−0.3084	−0.1196	0.112*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.038 (3)	0.060 (3)	0.047 (3)	−0.005 (2)	0.009 (2)	−0.005 (2)
O1	0.046 (2)	0.105 (3)	0.049 (2)	−0.0172 (19)	0.0083 (18)	−0.0083 (19)
C11	0.034 (2)	0.047 (2)	0.043 (3)	−0.0069 (19)	0.003 (2)	−0.001 (2)
C12	0.035 (2)	0.048 (2)	0.044 (3)	−0.0035 (19)	−0.002 (2)	0.008 (2)
Cl12	0.0471 (7)	0.0673 (8)	0.0685 (9)	0.0130 (6)	−0.0066 (6)	−0.0155 (6)
C13	0.049 (3)	0.049 (2)	0.047 (3)	−0.004 (2)	−0.003 (2)	−0.002 (2)
C14	0.041 (3)	0.052 (3)	0.057 (3)	−0.012 (2)	−0.016 (2)	0.012 (2)
Cl14	0.0676 (9)	0.0796 (9)	0.0751 (11)	−0.0176 (7)	−0.0345 (8)	0.0084 (7)
C15	0.028 (3)	0.073 (3)	0.072 (4)	0.003 (2)	−0.004 (3)	0.006 (3)
C16	0.039 (3)	0.069 (3)	0.057 (3)	−0.003 (2)	0.009 (3)	−0.005 (2)
C2	0.039 (3)	0.060 (3)	0.051 (3)	−0.008 (2)	0.001 (2)	−0.006 (2)
Br2	0.0519 (3)	0.0546 (3)	0.0794 (4)	−0.0009 (2)	0.0010 (3)	0.0113 (2)
C3	0.047 (3)	0.064 (3)	0.059 (3)	−0.015 (2)	−0.003 (3)	−0.012 (2)
Br3	0.0631 (4)	0.0594 (3)	0.0772 (4)	−0.0182 (2)	−0.0099 (3)	0.0201 (3)
C31	0.041 (3)	0.056 (3)	0.052 (3)	−0.013 (2)	−0.006 (2)	−0.007 (2)
C32	0.042 (3)	0.055 (3)	0.052 (3)	−0.011 (2)	−0.009 (2)	−0.004 (2)
C33	0.042 (3)	0.044 (2)	0.066 (3)	−0.006 (2)	−0.006 (2)	0.008 (2)
Br33	0.0480 (3)	0.0734 (4)	0.0972 (5)	−0.0069 (3)	0.0132 (3)	0.0007 (3)
C34	0.044 (3)	0.051 (3)	0.073 (4)	−0.013 (2)	−0.020 (3)	0.008 (3)
C35	0.067 (4)	0.052 (3)	0.061 (4)	−0.018 (3)	−0.024 (3)	0.001 (2)
C36	0.061 (3)	0.054 (3)	0.049 (3)	−0.010 (2)	−0.003 (3)	−0.007 (2)
O36	0.086 (3)	0.101 (3)	0.058 (2)	−0.029 (2)	0.008 (2)	−0.033 (2)
C361	0.122 (6)	0.071 (4)	0.063 (4)	−0.017 (4)	0.006 (4)	−0.017 (3)

Geometric parameters (Å, º)

C1—O1	1.212 (5)	C3—Br3	2.018 (5)
C1—C11	1.487 (6)	C3—H3	0.9800
C1—C2	1.523 (6)	C31—C36	1.381 (6)
C11—C12	1.387 (6)	C31—C32	1.381 (6)
C11—C16	1.391 (6)	C32—C33	1.385 (6)
C12—C13	1.380 (6)	C32—H32	0.9300
C12—Cl12	1.749 (5)	C33—C34	1.368 (7)
C13—C14	1.377 (7)	C33—Br33	1.898 (5)
C13—H13	0.9300	C34—C35	1.370 (8)
C14—C15	1.369 (7)	C34—H34	0.9300
C14—Cl14	1.736 (5)	C35—C36	1.387 (7)
C15—C16	1.379 (7)	C35—H35	0.9300
C15—H15	0.9300	C36—O36	1.368 (6)
C16—H16	0.9300	O36—C361	1.438 (6)
C2—C3	1.485 (7)	C361—H36A	0.9600
C2—Br2	2.007 (5)	C361—H36B	0.9600
C2—H2	0.9800	C361—H36C	0.9600
C3—C31	1.510 (6)
O1—C1—C11	120.0 (4)	C31—C3—Br3	110.0 (3)
O1—C1—C2	118.9 (4)	C2—C3—H3	109.3
C11—C1—C2	120.6 (4)	C31—C3—H3	109.3
C12—C11—C16	116.7 (4)	Br3—C3—H3	109.3
C12—C11—C1	127.2 (4)	C36—C31—C32	119.3 (4)
C16—C11—C1	116.0 (4)	C36—C31—C3	120.1 (4)
C13—C12—C11	122.6 (4)	C32—C31—C3	120.6 (4)
C13—C12—Cl12	115.6 (3)	C31—C32—C33	119.6 (4)
C11—C12—Cl12	121.7 (4)	C31—C32—H32	120.2
C14—C13—C12	118.0 (4)	C33—C32—H32	120.2
C14—C13—H13	121.0	C34—C33—C32	120.9 (5)
C12—C13—H13	121.0	C34—C33—Br33	119.7 (4)
C15—C14—C13	121.9 (4)	C32—C33—Br33	119.4 (4)
C15—C14—Cl14	119.1 (4)	C33—C34—C35	119.5 (5)
C13—C14—Cl14	119.0 (4)	C33—C34—H34	120.2
C14—C15—C16	118.7 (4)	C35—C34—H34	120.2
C14—C15—H15	120.7	C34—C35—C36	120.2 (5)
C16—C15—H15	120.7	C34—C35—H35	119.9
C15—C16—C11	122.1 (4)	C36—C35—H35	119.9
C15—C16—H16	119.0	O36—C36—C31	115.8 (4)
C11—C16—H16	119.0	O36—C36—C35	123.9 (5)
C3—C2—C1	115.0 (4)	C31—C36—C35	120.3 (5)
C3—C2—Br2	106.4 (3)	C36—O36—C361	119.1 (4)
C1—C2—Br2	104.1 (3)	O36—C361—H36A	109.5
C3—C2—H2	110.3	O36—C361—H36B	109.5
C1—C2—H2	110.3	H36A—C361—H36B	109.5
Br2—C2—H2	110.3	O36—C361—H36C	109.5
C2—C3—C31	115.9 (4)	H36A—C361—H36C	109.5
C2—C3—Br3	102.7 (3)	H36B—C361—H36C	109.5
O1—C1—C11—C12	140.4 (5)	Br2—C2—C3—C31	59.0 (5)
C2—C1—C11—C12	−48.3 (6)	C1—C2—C3—Br3	−66.3 (4)
O1—C1—C11—C16	−38.1 (6)	Br2—C2—C3—Br3	178.98 (19)
C2—C1—C11—C16	133.2 (4)	C2—C3—C31—C36	−132.5 (5)
C16—C11—C12—C13	1.6 (6)	Br3—C3—C31—C36	111.5 (4)
C1—C11—C12—C13	−177.0 (4)	C2—C3—C31—C32	47.4 (6)
C16—C11—C12—Cl12	177.7 (3)	Br3—C3—C31—C32	−68.5 (5)
C1—C11—C12—Cl12	−0.8 (6)	C36—C31—C32—C33	−1.5 (7)
C11—C12—C13—C14	−1.4 (6)	C3—C31—C32—C33	178.5 (4)
Cl12—C12—C13—C14	−177.7 (3)	C31—C32—C33—C34	−1.7 (7)
C12—C13—C14—C15	0.0 (7)	C31—C32—C33—Br33	179.1 (3)
C12—C13—C14—Cl14	179.1 (3)	C32—C33—C34—C35	3.7 (7)
C13—C14—C15—C16	1.0 (7)	Br33—C33—C34—C35	−177.1 (4)
Cl14—C14—C15—C16	−178.0 (4)	C33—C34—C35—C36	−2.4 (7)
C14—C15—C16—C11	−0.7 (7)	C32—C31—C36—O36	−179.1 (4)
C12—C11—C16—C15	−0.5 (7)	C3—C31—C36—O36	0.8 (7)
C1—C11—C16—C15	178.2 (4)	C32—C31—C36—C35	2.8 (7)
O1—C1—C2—C3	−23.5 (6)	C3—C31—C36—C35	−177.2 (5)
C11—C1—C2—C3	165.1 (4)	C34—C35—C36—O36	−178.8 (5)
O1—C1—C2—Br2	92.6 (5)	C34—C35—C36—C31	−0.9 (8)
C11—C1—C2—Br2	−78.8 (4)	C31—C36—O36—C361	171.0 (5)
C1—C2—C3—C31	173.7 (4)	C35—C36—O36—C361	−11.0 (8)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C32—H32···Br33^i	0.93	3.10	3.814 (5)	135
C361—H36A···Br3^ii	0.96	3.03	3.839 (7)	143
C361—H36B···Br2^iii	0.96	3.00	3.881 (6)	153

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