Do C—H⋯O and C—H⋯π inter­actions help to stabilize a non-centrosymmetric structure for racemic 2,3-dibromo-1,3-diphenyl­propan-1-one?

Harrison, W.T.A.; Yathirajan, H.S.; Sarojini, B.K.; Narayana, B.; Anilkumar, H.G.

doi:10.1107/S0108270105036942

organic compounds

STRUCTURAL
CHEMISTRY

ISSN: 2053-2296

Volume 61| Part 12| December 2005| Pages o728-o730

doi:10.1107/S0108270105036942

Do C—H⋯O and C—H⋯π interactions help to stabilize a non-centrosymmetric structure for racemic 2,3-dibromo-1,3-diphenylpropan-1-one?

William T. A. Harrison,^a ^* H. S. Yathirajan,^b B. K. Sarojini,^c B. Narayana ^d and H. G. Anilkumar ^b

^aDepartment of Chemistry, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, Scotland, ^bDepartment of Studies in Chemistry, University of Mysore, Manasagangotri, Mysore 570 006, India, ^cDepartment of Chemistry, P. A. College of Engineering, Nadupadavu, Mangalore 574 153, India, and ^dDepartment of Chemistry, Mangalore University, Mangalagangotri 574 199, India
^*Correspondence e-mail: w.harrison@abdn.ac.uk

(Received 31 October 2005; accepted 9 November 2005; online 30 November 2005)

The racemic title compound, C₁₅H₁₂Br₂O, crystallizes in a non-centrosymmetric structure and displays a significant non-linear optical response to red light. The crystal packing is influenced by C—H⋯O and C—H⋯π interactions. One of the former bonds has a short H⋯O separation of 2.27 Å.

Comment

In order to display non-linear optical (NLO) effects, organic molecular crystals must possess suitable electronic and structural properties. The former effects, including strong donor–acceptor intermolecular interactions and delocalized p-electron systems, are reasonably well understood (Watson et al., 1993 ). The latter effects – especially the ability to crystallize as a non-centrosymmetric structure – are harder to predict and control.

Among the many organic compounds reported for their NLO properties, chalcone derivatives are notable for their excellent blue light transmittance and good crystallizability. It is observed that the substitution of a bromo group on either of the benzene rings greatly influences the non-centrosymmetric crystal packing (Uchida et al., 1998 ; Tam et al., 1989 ; Indira et al., 2002 ). Bromo groups improve the molecular first-order hyperpolarizabilities and can effectively reduce dipole–dipole interactions between the molecules (Zhao et al., 2002 ). However, chalcone derivatives often have low melting temperatures, which can be a drawback with respect to the applications of these crystals in optical instruments. Chalcone dibromides usually have higher melting points and are thermally stable. We report here the synthesis and structure of the title compound, (I) (Fig. 1), which has a second harmonic generation (SHG) efficiency 0.4 times that of urea.

The non-centrosymmetric space group of (I) is consistent with the non-zero SHG signal observed. All the geometric parameters for (I) lie within their expected ranges (Allen et al., 1995 ). A dihedral angle of 22.58 (16)° occurs between the mean planes of the two benzene rings. With respect to the C7—C8 bond, the atom pairs Br1/Br2, C6/C9 and H7/H8 are all trans (Table 1). Each molecule of (I) is chiral (the arbitrarily chosen asymmetric molecule has R and S configurations for atoms C7 and C8, respectively), but space-group symmetry generates a racemic 1:1 mix of enantiomers, as might be expected in terms of the bromination reaction used to prepare (I), i.e. trans addition of the two Br atoms has occurred. However, (I) does not crystallize in a space group with inversion symmetry and a substantial SHG response arises.

The crystal packing of (I) appears to be influenced by weak interactions, including C—H⋯O and C—H⋯π bonds (Table 2). The three C—H⋯O interactions in (I) all link to the same acceptor O atom. One of the resulting H⋯O separations is rather short, at 2.27 Å. It may be assumed that these three H atoms are all `activated' (made more acidic) in terms of the identities of their adjacent atoms (Desiraju & Steiner, 1999 ). These C—H⋯O links result in parallel chains of molecules of (I) propagating in the c direction (Fig. 2). Within a chain, adjacent molecules, related by the c-glide operation, are enantiomers. For any adjacent pair of molecules in a chain, the dihedral angle between their C1-benzene rings is 50.50 (10)°. Fig. 2 shows that all the chains propagate in the same sense, i.e. all the C=O moieties point the same way, and it is tempting to assume that this `lining up' effect plays a role in defining the SHG properties of (I).

Furthermore, two C—H⋯π interactions appear to consolidate the crystal packing in (I) in the b direction. The two H atoms involved in these interactions are both trans to the C—C bond to the rest of the molecule. When viewed along the c direction (Fig. 3), it is observed that a herring-bone-like array of molecules of (I) results, with the C—H⋯π bonds forming infinite ladder-like chains along [010].

If the acceptor benzene ring is considered, then in each case it is notable that a Br atom is located roughly opposite the C—H⋯π interaction (Fig. 3) (H13⋯π1⋯Br2 = 168° and H3⋯π2⋯Br1 = 163°; π1 is the centroid of atoms C1–C6 and π2 is the centroid of atoms C10–C15). While this cannot be considered to be a Br⋯π `bond' of any kind [the Br⋯π separations of 3.661 and 3.884 Å are greater than the van der Waals separation of 3.55 Å for Br (1.85 Å) plus the half-thickness (1.70 Å) of a benzene ring], it is possible that this kind of intermolecular contact influences the SHG response of (I). The crystal packing of (I), viewed approximately down [010], is available as a figure in the supplementary material.

Figure 1
A view of (I)

, showing 50% probability displacement ellipsoids; H atoms are shown as arbitrary spheres.

Figure 2
A view of (I)

, showing how the three C—H⋯O interactions link adjacent molecules into parallel chains propagating in (001). H atoms not involved in the interactions shown have been omitted. [Symmetry codes: (i) x, −y + 1, z − $[{1\over 2}]$ ; (ii) x, −y + 1, z + $[{1\over 2}]$ .]

Figure 3
A detail of (I)

, showing how C—H⋯π interactions involving atoms H3 and H13 provide coherence between herring-bone-like sheets of molecules. Note also how a Br atom is positioned approximately trans to every C—H⋯π bond (see Comment). H atoms not involved in the interactions shown have been omitted. [Symmetry codes: (v) x, y + 1, z; (vi) x, y − 1, z.]

Experimental

Chalcone (1,3-diphenyl-2-propen-1-one) (20.8 g 0.1 mol) was treated with 30% bromine in acetic acid until the orange colour of the solution just persisted. After stirring for 30 min, the contents of the flask were poured onto crushed ice and the resulting crude solid was collected by filtration. The compound was dried and recrystallized as clear blocks of (I) from ethanol in 85% yield (m.p. 396–398 K). Analysis for C₁₅H₁₂Br₂O requires: C 48.95, H 3.29%; found: C 48.91, H 3.26%. The SHG efficiency of (I), normalized to that of urea, was measured by a standard powder technique (Kurtz & Perry, 1968 ) using an Nd:YAG laser.

Crystal data

C₁₅H₁₂Br₂O
M_r = 368.07
Monoclinic, C c
a = 20.6762 (7) Å
b = 7.2443 (2) Å
c = 10.3501 (3) Å
β = 116.575 (2)°
V = 1386.50 (7) Å³
Z = 4
D_x = 1.763 Mg m⁻³
Mo Kα radiation
Cell parameters from 4476 reflections
θ = 2.9–27.5°
μ = 5.83 mm⁻¹
T = 120 (2) K
Block, colourless
0.48 × 0.32 × 0.18 mm

Data collection

Nonius KappaCCD diffractometer
ω and φ scans
Absorption correction: multi-scan(SADABS; Bruker, 1999 )T_min = 0.138, T_max = 0.350
9478 measured reflections
3011 independent reflections
2889 reflections with I > 2σ(I)
R_int = 0.029
θ_max = 27.5°
h = −26 → 26
k = −9 → 9
l = −12 → 13

Refinement

Refinement on F²
R[F² > 2σ(F²)] = 0.026
wR(F²) = 0.058
S = 1.05
3011 reflections
164 parameters
H-atom parameters constrained
w = 1/[σ²(F_o²) + 3.0761P] where P = (F_o² + 2F_c²)/3
(Δ/σ)_max = 0.001
Δρ_max = 1.05 e Å⁻³
Δρ_min = −0.74 e Å⁻³
Extinction correction: SHELXL97
Extinction coefficient: 0.0035 (2)
Absolute structure: Flack (1983 ), 1416 Friedel pairs
Flack parameter: 0.022 (11)

Table 1
Selected torsion angles (°)

C6—C7—C8—C9	169.9 (3)
Br1—C7—C8—Br2	175.33 (16)

Table 2
Intermolecular interactions (Å, °)

π1 is the centroid of the C1–C6 ring and π2 is the centroid of the C10–C15 ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C5—H5⋯O1ⁱ	0.95	2.55	3.469 (4)	162
C8—H8⋯O1ⁱ	1.00	2.27	3.237 (4)	163
C11—H11⋯O1ⁱ	0.95	2.57	3.370 (4)	142
C13—H13⋯π1ⁱⁱⁱ	0.95	2.91	3.629 (4)	133
C3—H3⋯π2^iv	0.95	2.99	3.590 (3)	123
Symmetry codes: (i) $[x, -y+1, z-{\script{1\over 2}}]$ ; (iii) $[x+{\script{1\over 2}}, -y+{\script{3\over 2}}, z+{\script{1\over 2}}]$ ; (iv) $[x-{\script{1\over 2}}, -y+{\script{1\over 2}}, z-{\script{1\over 2}}]$ .

The H atoms were positioned geometrically (C—H = 0.95–1.00 Å) and refined as riding, with U_iso(H) = 1.2U_eq(carrier).

Data collection: COLLECT (Nonius, 1998 ); cell refinement: SCALEPACK (Otwinowski & Minor, 1997 ); data reduction: SCALEPACK, DENZO (Otwinowski & Minor, 1997) and SORTAV (Blessing, 1995 ); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997 ), ATOMS (Shape Software, 2003 ) and PLATON (Spek, 2003 ); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S0108270105036942/fg1880sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S0108270105036942/fg1880Isup2.hkl

Supporting information file. DOI: 10.1107/S0108270105036942/fg1880sup4.pdf

Comment top

In order to display nonlinear optical (NLO) effects, organic molecular crystals must possess suitable electronic and structural properties. The former effects, including strong donor–acceptor intermolecular interactions and delocalized p-electron systems, are reasonably well understood (Watson et al., 1993). The latter effects – especially the ability to crystallize as a non-centrosymmetric structure – are harder to predict and control.

Among the many organic compounds reported for their NLO properties, chalcone (C₁₅H₁₂O) derivatives are notable for their excellent blue light transmittance and good crystallizability. It is observed that the substitution of a bromo group on either of the benzene rings greatly influences the non-centrosymmetric crystal packing (Uchida et al., 1998; Tam et al., 1989; Indira et al., 2002). Bromo groups improve the molecular first-order hyperpolarizabilities and can effectively reduce dipole–dipole interactions between the molecules (Zhao et al., 2002). However, chalcone derivatives often have low melting temperatures, which can be a drawback with respect to the applications of these crystals in optical instruments. Chalcone dibromides usually have higher meting points and are thermally stable. We report here the synthesis and structure of the title compound, (I) (Fig. 1), which has a second harmonic generation (SHG) efficiency 0.4 times that of urea.

The non-centrosymmetric space group of (I) is consistent with the non-zero SHG signal observed. All the gemoetrical parameters for (I) lie within their expected ranges (Allen et al., 1995). A dihedral angle of 22.58 (16)° occurs between the two benzene ring C-atom mean planes. With respect to the C7—C8 bond, the atom pairs Br1 and Br2, C6 and C9, and H7 and H8 are all trans (Table 1). Each molecule of (I) is chiral (the arbitrarly chosen asymmetric molecule has R and S configurations for atoms C7 and C8, respectively), but space-group symmetry generates a racemic 50:50 mix of enantiomers, as might be expected in terms of the bromination reaction that prepared (I), i.e. trans addition of the two Br atoms has occurred. However, (I) does not crystallize in a space group with inversion symmetry and a substantial SHG response arises.

The crystal packing of (I) appears to be influenced by weak interactions including C—H···O and C—H···π bonds (Table 2). The three C—H···O interactions in (I) all link to the same acceptor O atom. One of the resulting H···O separations is rather short, at 2.27 Å. It may be assumed that these three H atoms are all `activated' (made more acidic) in terms of the identities of their adjacent atoms (Desiraju & Steiner, 1999). These C—H···O links result in parallel chains of molecules of (I) propagating in the c direction (Fig. 2). Within a chain, adjacent molecules, related by the c-glide operation are enantiomers. For any adjacent pair of molecules in a chain, the dihedral angle between their C1-benzene rings is 50.50 (10)°. Fig. 2 shows that all the chains propagate in the same sense, i.e. all the C═O moieties point the same way, and it is tempting to assume that this `lining up' effect plays a role in defining the SHG properties of (I).

Secondly, two C—H···π interactions appear to consolidate the crystal packing in (I) in the b direction. The two H atoms involved in these interactins are both trans to the C—C bond to the rest of the molecule. When viewed down the c direction (Fig. 3), it is observed that a herringbone-like array of molecules of (I) results, with the C—H···π bonds forming infinite ladder-like chains along [010].

If the acceptor benzene ring is considered, then in each case it is notable that a Br atom is located roughly opposite the C—H···π interaction (Fig. 3) (H13···π1···Br2 = 168° and H3···π2···Br1 = 163°; π1 = centroid of atoms C1–C6 and π2 = centroid of atoms C10–C15). While this cannot be considered to be a Br···π `bond' of any kind [the Br···π separations of 3.661 and 3.884 Å are greater than the van der Waals separation of 3.55 Å for Br (1.85 Å) + the half-thickness (1.70 Å) of a benzene ring], it is possible that this kind of intermolecular contact influences the SHG response of (I). The crystal packing of (I) viewed approximately down [010] is shown in Fig. 4, which is available in the Supplementary Material.

Experimental top

Chalcone [1-(phenyl)-3-(phenyl)-2-propen-1-one] (20.8 g 0.1 mol) was treated with 30% bromine in acetic acid until the orange colour of the solution just persisted. After stirring for 30 min, the contents of the flask were poured onto crushed ice and the resulting crude solid was collected by filtration. The compound was dried and recrystallized as clear blocks of (I) from ethanol in 85% yield (m.p. 396–398 K). Analysis C₁₅H₁₂Br₂O requires: C 48.95, H 3.29%; found: C 48.91, H 3.26%. The SHG efficiency of (I), normalized to that of urea, was measured by a standard powder technique (Kurtz & Perry, 1968) using an Nd:YAG laser.

Computing details top

Data collection: COLLECT (Nonius, 1998); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: SCALEPACK, DENZO (Otwinowski & Minor, 1997) and SORTAV (Blessing, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997), ATOMS (Shape Software, 2003) and PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97.

Figures top

Fig. 1. A view of (I), showing 50% probability displacement ellipsoids and arbitrary spheres for the H atoms.

Fig. 2. A view of (I), showing how the three C—H···O interactions link adjacent molecules into parallel chains propagating in (001). H atoms not involved in the interactions shown have been omitted. [Symmetry codes: (i) x, 1 − y, z − 1/2; (ii) x, 1 − y, z + 1/2.]

Fig. 3. Detail of (I), showing how C—H···π interactions involving atoms H3 and H13 provide coherence between herringbone-like sheets of molecules. Note also how a Br atom is positioned approximately trans to every C—H···π bond (see text). H atoms not involved in the interactions shown have been omitted. [Symmetry codes: (iv) x, y + 1, z; (v) x, y − 1, z.]

###### Figure 4 is to go to Supplementary Material #### Fig. 4. Unit cell packing in (I), viewed approximately down [010]. ######

2,3-dibromo-1,3-diphenylpropan-1-one top

Crystal data top

C₁₅H₁₂Br₂O	F(000) = 720
M_r = 368.07	D_x = 1.763 Mg m⁻³
Monoclinic, Cc	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: C -2yc	Cell parameters from 4476 reflections
a = 20.6762 (7) Å	θ = 2.9–27.5°
b = 7.2443 (2) Å	µ = 5.83 mm⁻¹
c = 10.3501 (3) Å	T = 120 K
β = 116.575 (2)°	Block, colourless
V = 1386.50 (7) Å³	0.48 × 0.32 × 0.18 mm
Z = 4

Data collection top

Nonius KappaCCD diffractometer	3011 independent reflections
Radiation source: fine-focus sealed tube	2889 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.029
ω and ϕ scans	θ_max = 27.5°, θ_min = 3.0°
Absorption correction: multi-scan (SADABS; Bruker, 1999)	h = −26→26
T_min = 0.138, T_max = 0.350	k = −9→9
9478 measured reflections	l = −12→13

Refinement top

Refinement on F²	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F² > 2σ(F²)] = 0.026	w = 1/[σ²(F_o²) + 3.0761P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.058	(Δ/σ)_max = 0.001
S = 1.05	Δρ_max = 1.05 e Å⁻³
3011 reflections	Δρ_min = −0.74 e Å⁻³
164 parameters	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
2 restraints	Extinction coefficient: 0.0035 (2)
Primary atom site location: structure-invariant direct methods	Absolute structure: Flack (1983), 1416 Friedel pairs
Secondary atom site location: difference Fourier map	Absolute structure parameter: 0.022 (11)

Crystal data top

C₁₅H₁₂Br₂O	V = 1386.50 (7) Å³
M_r = 368.07	Z = 4
Monoclinic, Cc	Mo Kα radiation
a = 20.6762 (7) Å	µ = 5.83 mm⁻¹
b = 7.2443 (2) Å	T = 120 K
c = 10.3501 (3) Å	0.48 × 0.32 × 0.18 mm
β = 116.575 (2)°

Data collection top

Nonius KappaCCD diffractometer	3011 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 1999)	2889 reflections with I > 2σ(I)
T_min = 0.138, T_max = 0.350	R_int = 0.029
9478 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.026	H-atom parameters constrained
wR(F²) = 0.058	Δρ_max = 1.05 e Å⁻³
S = 1.05	Δρ_min = −0.74 e Å⁻³
3011 reflections	Absolute structure: Flack (1983), 1416 Friedel pairs
164 parameters	Absolute structure parameter: 0.022 (11)
2 restraints

Special details top

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) top

	x	y	z	U_iso*/U_eq
C1	0.04577 (19)	0.2245 (5)	0.2084 (4)	0.0229 (7)
H1	0.0433	0.2559	0.2953	0.028*
C2	−0.0125 (2)	0.1409 (5)	0.0969 (4)	0.0298 (8)
H2	−0.0546	0.1115	0.1077	0.036*
C3	−0.0091 (2)	0.0998 (6)	−0.0313 (5)	0.0352 (10)
H3	−0.0490	0.0416	−0.1081	0.042*
C4	0.0517 (2)	0.1433 (5)	−0.0472 (4)	0.0317 (9)
H4	0.0531	0.1193	−0.1362	0.038*
C5	0.1101 (2)	0.2210 (6)	0.0651 (4)	0.0304 (9)
H5	0.1527	0.2468	0.0551	0.036*
C6	0.1074 (2)	0.2624 (5)	0.1938 (4)	0.0251 (7)
C7	0.1722 (2)	0.3415 (5)	0.3225 (4)	0.0249 (8)
H7	0.1571	0.3771	0.3984	0.030*
C8	0.20890 (19)	0.5037 (5)	0.2922 (4)	0.0231 (7)
H8	0.2324	0.4647	0.2306	0.028*
C9	0.26462 (18)	0.5947 (5)	0.4315 (3)	0.0183 (7)
C10	0.32549 (18)	0.7013 (4)	0.4283 (4)	0.0177 (7)
C11	0.32995 (18)	0.7413 (5)	0.3006 (4)	0.0196 (7)
H11	0.2934	0.6986	0.2108	0.023*
C12	0.3877 (2)	0.8432 (5)	0.3043 (4)	0.0267 (8)
H12	0.3907	0.8698	0.2172	0.032*
C13	0.44080 (19)	0.9059 (5)	0.4351 (4)	0.0250 (8)
H13	0.4802	0.9762	0.4377	0.030*
C14	0.43665 (19)	0.8659 (5)	0.5635 (4)	0.0248 (8)
H14	0.4735	0.9075	0.6533	0.030*
C15	0.37951 (18)	0.7667 (5)	0.5597 (4)	0.0200 (7)
H15	0.3764	0.7420	0.6469	0.024*
O1	0.25723 (13)	0.5821 (3)	0.5409 (2)	0.0228 (5)
Br1	0.25056 (2)	0.15595 (6)	0.40367 (4)	0.03696 (13)
Br2	0.135629 (16)	0.70222 (4)	0.19289 (2)	0.02462 (10)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0256 (19)	0.0207 (18)	0.0258 (19)	−0.0026 (14)	0.0146 (16)	−0.0011 (14)
C2	0.025 (2)	0.0261 (19)	0.038 (2)	−0.0064 (15)	0.0142 (17)	0.0027 (16)
C3	0.042 (2)	0.025 (2)	0.030 (2)	−0.0110 (18)	0.0074 (18)	−0.0032 (16)
C4	0.040 (2)	0.028 (2)	0.0212 (19)	−0.0132 (17)	0.0085 (16)	−0.0022 (15)
C5	0.031 (2)	0.038 (2)	0.025 (2)	−0.0117 (17)	0.0148 (17)	−0.0087 (16)
C6	0.0215 (17)	0.0309 (19)	0.0217 (17)	−0.0040 (16)	0.0087 (14)	−0.0026 (15)
C7	0.0287 (19)	0.0246 (19)	0.0223 (18)	−0.0019 (15)	0.0122 (15)	−0.0013 (14)
C8	0.0235 (17)	0.0290 (19)	0.0197 (18)	−0.0041 (14)	0.0122 (14)	−0.0030 (14)
C9	0.0202 (17)	0.0195 (16)	0.0173 (18)	−0.0022 (13)	0.0103 (14)	0.0010 (13)
C10	0.0145 (16)	0.0199 (17)	0.0190 (17)	0.0008 (13)	0.0077 (13)	−0.0009 (13)
C11	0.0175 (16)	0.0220 (16)	0.0191 (17)	−0.0029 (14)	0.0081 (13)	−0.0008 (14)
C12	0.029 (2)	0.0255 (19)	0.030 (2)	−0.0033 (16)	0.0162 (16)	0.0032 (15)
C13	0.0167 (17)	0.0251 (19)	0.033 (2)	−0.0037 (14)	0.0105 (15)	−0.0036 (15)
C14	0.0196 (17)	0.0245 (19)	0.0254 (19)	−0.0034 (15)	0.0056 (14)	−0.0092 (15)
C15	0.0237 (18)	0.0207 (18)	0.0168 (17)	−0.0022 (15)	0.0103 (14)	−0.0024 (14)
O1	0.0277 (13)	0.0280 (13)	0.0179 (12)	−0.0078 (11)	0.0148 (10)	−0.0050 (10)
Br1	0.0402 (3)	0.0285 (2)	0.0265 (2)	0.01339 (19)	0.00092 (17)	−0.00273 (17)
Br2	0.02293 (18)	0.01999 (17)	0.02441 (18)	−0.00064 (15)	0.00476 (13)	0.00198 (15)

Geometric parameters (Å, º) top

C1—C6	1.377 (5)	C8—Br2	2.007 (4)
C1—C2	1.381 (5)	C8—H8	1.0000
C1—H1	0.9500	C9—O1	1.212 (4)
C2—C3	1.392 (6)	C9—C10	1.490 (5)
C2—H2	0.9500	C10—C11	1.395 (5)
C3—C4	1.376 (6)	C10—C15	1.401 (5)
C3—H3	0.9500	C11—C12	1.390 (5)
C4—C5	1.368 (6)	C11—H11	0.9500
C4—H4	0.9500	C12—C13	1.384 (5)
C5—C6	1.390 (5)	C12—H12	0.9500
C5—H5	0.9500	C13—C14	1.400 (5)
C6—C7	1.516 (5)	C13—H13	0.9500
C7—C8	1.506 (5)	C14—C15	1.368 (5)
C7—Br1	1.980 (4)	C14—H14	0.9500
C7—H7	1.0000	C15—H15	0.9500
C8—C9	1.534 (5)

C6—C1—C2	120.0 (3)	C9—C8—Br2	104.5 (2)
C6—C1—H1	120.0	C7—C8—H8	110.2
C2—C1—H1	120.0	C9—C8—H8	110.2
C1—C2—C3	119.6 (3)	Br2—C8—H8	110.2
C1—C2—H2	120.2	O1—C9—C10	121.4 (3)
C3—C2—H2	120.2	O1—C9—C8	119.3 (3)
C4—C3—C2	120.2 (4)	C10—C9—C8	119.2 (3)
C4—C3—H3	119.9	C11—C10—C15	119.2 (3)
C2—C3—H3	119.9	C11—C10—C9	122.9 (3)
C5—C4—C3	120.0 (4)	C15—C10—C9	117.9 (3)
C5—C4—H4	120.0	C12—C11—C10	120.3 (3)
C3—C4—H4	120.0	C12—C11—H11	119.9
C4—C5—C6	120.3 (4)	C10—C11—H11	119.9
C4—C5—H5	119.8	C13—C12—C11	119.8 (3)
C6—C5—H5	119.8	C13—C12—H12	120.1
C1—C6—C5	119.9 (3)	C11—C12—H12	120.1
C1—C6—C7	118.4 (3)	C12—C13—C14	120.1 (3)
C5—C6—C7	121.7 (3)	C12—C13—H13	119.9
C8—C7—C6	116.2 (3)	C14—C13—H13	119.9
C8—C7—Br1	103.0 (2)	C15—C14—C13	120.0 (3)
C6—C7—Br1	110.5 (3)	C15—C14—H14	120.0
C8—C7—H7	109.0	C13—C14—H14	120.0
C6—C7—H7	109.0	C14—C15—C10	120.5 (3)
Br1—C7—H7	109.0	C14—C15—H15	119.7
C7—C8—C9	112.1 (3)	C10—C15—H15	119.7
C7—C8—Br2	109.3 (2)

C6—C1—C2—C3	−1.7 (6)	C7—C8—C9—O1	−26.4 (4)
C1—C2—C3—C4	−0.4 (6)	Br2—C8—C9—O1	91.9 (3)
C2—C3—C4—C5	2.4 (6)	C7—C8—C9—C10	155.4 (3)
C3—C4—C5—C6	−2.3 (6)	Br2—C8—C9—C10	−86.3 (3)
C2—C1—C6—C5	1.8 (6)	O1—C9—C10—C11	−170.5 (3)
C2—C1—C6—C7	−175.6 (3)	C8—C9—C10—C11	7.7 (5)
C4—C5—C6—C1	0.2 (6)	O1—C9—C10—C15	8.2 (5)
C4—C5—C6—C7	177.5 (4)	C8—C9—C10—C15	−173.6 (3)
C1—C6—C7—C8	−133.7 (4)	C15—C10—C11—C12	0.6 (5)
C5—C6—C7—C8	48.9 (5)	C9—C10—C11—C12	179.3 (3)
C1—C6—C7—Br1	109.4 (3)	C10—C11—C12—C13	−0.2 (6)
C5—C6—C7—Br1	−68.0 (4)	C11—C12—C13—C14	0.4 (6)
C6—C7—C8—C9	169.9 (3)	C12—C13—C14—C15	−0.9 (6)
Br1—C7—C8—C9	−69.2 (3)	C13—C14—C15—C10	1.2 (5)
C6—C7—C8—Br2	54.4 (3)	C11—C10—C15—C14	−1.1 (5)
Br1—C7—C8—Br2	175.33 (16)	C9—C10—C15—C14	−179.9 (3)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C5—H5···O1ⁱ	0.95	2.55	3.469 (4)	162
C8—H8···O1ⁱ	1.00	2.27	3.237 (4)	163
C11—H11···O1ⁱ	0.95	2.57	3.370 (4)	142
C13—H13···π1ⁱⁱ	0.95	2.91	3.629 (4)	133
C3—H3···π2ⁱⁱⁱ	0.95	2.99	3.590 (3)	123

Symmetry codes: (i) x, −y+1, z−1/2; (ii) x+1/2, −y+3/2, z+1/2; (iii) x−1/2, −y+1/2, z−1/2.

Experimental details

Crystal data
Chemical formula	C₁₅H₁₂Br₂O
M_r	368.07
Crystal system, space group	Monoclinic, Cc
Temperature (K)	120
a, b, c (Å)	20.6762 (7), 7.2443 (2), 10.3501 (3)
β (°)	116.575 (2)
V (Å³)	1386.50 (7)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	5.83
Crystal size (mm)	0.48 × 0.32 × 0.18

Data collection
Diffractometer	Nonius KappaCCD diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 1999)
T_min, T_max	0.138, 0.350
No. of measured, independent and observed [I > 2σ(I)] reflections	9478, 3011, 2889
R_int	0.029
(sin θ/λ)_max (Å⁻¹)	0.649

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.026, 0.058, 1.05
No. of reflections	3011
No. of parameters	164
No. of restraints	2
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	1.05, −0.74
Absolute structure	Flack (1983), 1416 Friedel pairs
Absolute structure parameter	0.022 (11)

Computer programs: COLLECT (Nonius, 1998), SCALEPACK (Otwinowski & Minor, 1997), SCALEPACK, DENZO (Otwinowski & Minor, 1997) and SORTAV (Blessing, 1995), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEP-3 (Farrugia, 1997), ATOMS (Shape Software, 2003) and PLATON (Spek, 2003), SHELXL97.

Selected torsion angles (º) top

C6—C7—C8—C9

169.9 (3)

Br1—C7—C8—Br2

175.33 (16)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C5—H5···O1ⁱ	0.95	2.55	3.469 (4)	162
C8—H8···O1ⁱ	1.00	2.27	3.237 (4)	163
C11—H11···O1ⁱ	0.95	2.57	3.370 (4)	142
C13—H13···π1ⁱⁱ	0.95	2.91	3.629 (4)	133
C3—H3···π2ⁱⁱⁱ	0.95	2.99	3.590 (3)	123

Symmetry codes: (i) x, −y+1, z−1/2; (ii) x+1/2, −y+3/2, z+1/2; (iii) x−1/2, −y+1/2, z−1/2.

Acknowledgements

The authors thank the EPSRC National Crystallography Service (University of Southampton, England) for the data collection. HGA thanks the University of Mysore for provision of facilities.

References

Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1995). International Tables for Crystallography, Vol. C, pp. 685–706. Dordrecht: Kluwer Academic Publishers. Google Scholar
Blessing, R. H. (1995). Acta Cryst. A51, 33–38. CrossRef CAS Web of Science IUCr Journals Google Scholar
Bruker (1999). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Desiraju, G. R. & Steiner, T. (1999). The Weak Hydrogen Bond in Structural Chemistry and Biology, p. 50. Oxford University Press. Google Scholar
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565. CrossRef IUCr Journals Google Scholar
Flack, H. D. (1983). Acta Cryst. A39, 876–881. CrossRef CAS Web of Science IUCr Journals Google Scholar
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Shape Software (2003). ATOMS. Shape Software, 525 Hidden Valley Road, Kingsport, Tennessee, USA. Google Scholar
Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany. Google Scholar
Spek, A. L. (2003). J. Appl. Cryst. 36, 7–13. Web of Science CrossRef CAS IUCr Journals Google Scholar
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Volume 61| Part 12| December 2005| Pages o728-o730

doi:10.1107/S0108270105036942

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organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Do C—H⋯O and C—H⋯π inter­actions help to stabilize a non-centrosymmetric structure for racemic 2,3-di­bromo-1,3-di­phenyl­propan-1-one?

Comment

Experimental

Crystal data

Data collection

Refinement

Supporting information

Acknowledgements

References

organic compounds

Do C—H⋯O and C—H⋯π interactions help to stabilize a non-centrosymmetric structure for racemic 2,3-dibromo-1,3-diphenylpropan-1-one?