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The structure of 4,4'-di­bromo­benzo­phenone, C13H8Br2O, was determined at two different temperatures (293 and 103 K). A phase transition was not detected in this temperature range. Its crystal structure was found to be isostructural with that of the di­iodo analogue, but not with the structure of the di­chloro derivative.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270199013839/sk1339sup1.cif
Contains datablocks global, I, II

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270199013839/sk1339Isup2.hkl
Contains datablock I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270199013839/sk1339IIsup3.hkl
Contains datablock II

CCDC references: 142758; 142759

Comment top

Molecules of 4,4'-halogenated-benzophenones and their precursor benzophenone, in accord with the hybridization of the atoms involved, should be planar. However, the steric hindrances introduced by the hydrogen atoms (overcrowding effect) have caused puckering of these molecules. The halogenated molecules exhibit C2 symmetry with a crystallographic twofold axes through a carbonyl bond whereas benzophenone reveals an approximate C2 molecular symmetry. The puckering of the benzophenone skeleton can be illustrated by the dihedral angle between two phenyl rings. In these compounds their values range from 48.9 to 55.8° (4,4'-difluorobenzophenone 48.9°, Manginn & Davey, 1994; 4,4'-dichlorobenzophenone, room temperature phase 50.5°, Granger & Coillot, 1985; 4,4'-dichlorobenzophenone, low temperature phase 49.3°, Zúñiga & Criado, 1995; 4,4'-diiodobenzophenone 50.1°, van der Velden & Noordik, 1979, and benzophenone 55.8°, Fleischer et al., 1968). The existence of the phase transition of 4,4'-dichlorobenzophenone (Zúñiga & Criado, 1995) and the temperature dependent Raman spectra of 4,4'-dibromobenzophenone (Volovšek et al., 1995), motivated us to investigate the X-ray structure of 4,4'-dibromobenzophenone, (I), in the temperature range 100 K to 293 K. In order to provide more information, the unit cell and the possible phase transition were examined at 293 K, 223 K, 163 K and 103 K. For the unit cell determinations 25 reflections at high θ angle were used and additional ten reflections were examined on possible intensity changes. The correlation of the unit-cell dimensions with temperature revealed that Δa/a 5Δb/b 5Δc/c. An assumption that this effect might be related with the changes of dihedral angle between phenyl rings was not justified by the crystal structure determination at two different temperatures [50.10 (12)° at 293 K and 49.60 (15)° at 103 K]. Thus, our data have not revealed the change of the space group (Ccc2). The ORTEPII (Johnson, 1976) plot (Fig. 1) and crystal packing (Fig. 2) of 4,4'-dibromobenzophenone show the structure solved from low temperature data. The crystal packing (Fig. 2) is determined by van der Waals interactions. This type of packing is isostructural with that of the diiodo analogue (van der Velden & Noordik, 1979) but not with the packing of difluoro (Manginn & Davey, 1994) and dichloro (Granger & Coilot, 1985; Zúñiga & Criado, 1995) analogues. The carbonyl bonds of the dibromo and diiodo analogues are oriented along the polar twofold axes running along the c axes (in the space group Ccc2, Fig. 2). As the consequence of the space group symmetry a uniform orientation of the parallel polar groups (carbonyl) is maintained.

Experimental top

The title compound, commercially available (ICN Pharmaceuticals Inc., Plainview, NY) was recrystallized from pure benzene solution at room temperature. Structure determination was performed with two data sets measured at 293 K (Data set I) and at 103 K (Data set II) using the same sample.

Refinement top

The absorption correction was done using Meulenaer-Tompa analytical method (Meulenaer & Tompa, 1965) incorporated in PLATON computer program (Spek, 1998). All hydrogen atoms were located from difference Fourier map and refined without constraints.

Computing details top

Data collection: CAD-4 EXPRESS (Enraf-Nonius, 1992) for (I); CAD-4 EXPRESS (Enraf Nonius, 1992) for (II). For both compounds, cell refinement: CAD-4 EXPRESS and CELDIM routine; data reduction: HELENA (Spek, 1997); program(s) used to solve structure: SIR97 (Altomare et al., 1996); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 1998); software used to prepare material for publication: PLATON.

Figures top
[Figure 1] Fig. 1. The structure of the title compound using Data set II, recorded at 103 K. Displacement ellipsoids are scaled at the 30% level.
[Figure 2] Fig. 2. Crystal packing shows polar regions composed of bromine atoms separated by aromatic systems.
(I) 4,4'-dibromobenzophenone top
Crystal data top
C13H8Br2OF(000) = 656
Mr = 339.99Dx = 1.887 Mg m3
Orthorhombic, Ccc2Cu Kα radiation, λ = 1.54184 Å
Hall symbol: C 2 -2ycCell parameters from 25 reflections
a = 7.3969 (4) Åθ = 43.9–47.7°
b = 26.7030 (9) ŵ = 8.38 mm1
c = 6.0594 (3) ÅT = 293 K
V = 1196.85 (10) Å3Prism, colourless
Z = 40.18 × 0.14 × 0.07 mm
Data collection top
Enraf-Nonius CAD-4
diffractometer
581 reflections with I > 2σ(I)
Radiation source: fine-focused sealed tubeRint = 0.000
Graphite monochromatorθmax = 74.1°, θmin = 3.3°
ω/2θ scansh = 09
Absorption correction: analytical
(PLATON; Spek, 1998)
k = 330
Tmin = 0.386, Tmax = 0.591l = 07
744 measured reflections3 standard reflections every 60 min
679 independent reflections intensity decay: 0.8%
Refinement top
Refinement on F2Calculated w = 1/[σ2(Fo2) + (0.0378P)2 + 0.3857P]
where P = (Fo2 + 2Fc2)/3
Least-squares matrix: full(Δ/σ)max = 0.001
R[F2 > 2σ(F2)] = 0.022Δρmax = 0.24 e Å3
wR(F2) = 0.066Δρmin = 0.25 e Å3
S = 1.05Extinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
679 reflectionsExtinction coefficient: 0.00085 (11)
91 parametersAbsolute structure: Flack (1983)
1 restraintAbsolute structure parameter: 0.02 (4)
All H-atom parameters refined
Crystal data top
C13H8Br2OV = 1196.85 (10) Å3
Mr = 339.99Z = 4
Orthorhombic, Ccc2Cu Kα radiation
a = 7.3969 (4) ŵ = 8.38 mm1
b = 26.7030 (9) ÅT = 293 K
c = 6.0594 (3) Å0.18 × 0.14 × 0.07 mm
Data collection top
Enraf-Nonius CAD-4
diffractometer
581 reflections with I > 2σ(I)
Absorption correction: analytical
(PLATON; Spek, 1998)
Rint = 0.000
Tmin = 0.386, Tmax = 0.5913 standard reflections every 60 min
744 measured reflections intensity decay: 0.8%
679 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.022All H-atom parameters refined
wR(F2) = 0.066Δρmax = 0.24 e Å3
S = 1.05Δρmin = 0.25 e Å3
679 reflectionsAbsolute structure: Flack (1983)
91 parametersAbsolute structure parameter: 0.02 (4)
1 restraint
Special details top

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All e.s.d.'s are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

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
xyzUiso*/Ueq
Br0.27572 (7)0.04457 (1)0.60433 (10)0.0835 (2)
O0.250000.250001.2615 (7)0.0706 (18)
C10.250000.250001.0600 (8)0.0447 (16)
C20.2476 (4)0.20123 (14)0.9414 (6)0.0404 (10)
C30.3244 (4)0.19552 (12)0.7313 (5)0.0380 (9)
C40.3341 (5)0.14898 (12)0.6338 (7)0.0443 (10)
C50.2629 (5)0.10770 (14)0.7433 (7)0.0495 (11)
C60.1862 (6)0.11297 (16)0.9492 (8)0.0563 (12)
C70.1792 (5)0.15910 (17)1.0471 (6)0.0502 (11)
H30.366 (4)0.2235 (12)0.665 (6)0.038 (9)*
H40.382 (6)0.1440 (13)0.489 (7)0.050 (11)*
H60.141 (6)0.0841 (16)1.009 (8)0.069 (13)*
H70.124 (5)0.1630 (15)1.192 (6)0.047 (11)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br0.1008 (4)0.0463 (3)0.1034 (4)0.0032 (2)0.0013 (6)0.0070 (3)
O0.104 (4)0.078 (3)0.0298 (18)0.022 (3)0.00000.0000
C10.044 (2)0.055 (3)0.035 (3)0.0102 (19)0.00000.0000
C20.0340 (15)0.054 (2)0.0331 (17)0.0063 (13)0.0017 (13)0.0052 (13)
C30.0389 (15)0.0455 (16)0.0295 (15)0.0015 (13)0.0013 (14)0.0060 (13)
C40.0467 (17)0.0488 (15)0.0374 (18)0.0036 (12)0.0034 (17)0.0009 (18)
C50.0503 (19)0.0423 (17)0.056 (2)0.0051 (14)0.0059 (18)0.0006 (18)
C60.055 (2)0.054 (2)0.060 (2)0.0052 (16)0.007 (2)0.0173 (18)
C70.0407 (18)0.071 (2)0.039 (2)0.0031 (17)0.0074 (14)0.0142 (16)
Geometric parameters (Å, º) top
Br—C51.887 (4)C5—C61.378 (6)
O—C11.221 (6)C6—C71.368 (6)
C1—C21.488 (4)C3—H30.90 (3)
C2—C31.402 (5)C4—H40.96 (4)
C2—C71.390 (6)C6—H60.92 (4)
C3—C41.378 (5)C7—H70.97 (4)
C4—C51.390 (5)
O—C1—C2118.9 (2)C5—C6—C7120.0 (4)
O—C1—C2i118.9 (2)C2—C7—C6121.0 (4)
C2—C1—C2i122.2 (4)C2—C3—H3117 (2)
C1—C2—C3121.9 (3)C4—C3—H3123 (2)
C1—C2—C7119.4 (3)C3—C4—H4123 (2)
C3—C2—C7118.5 (3)C5—C4—H4118 (2)
C2—C3—C4120.6 (3)C5—C6—H6115 (3)
C3—C4—C5119.4 (4)C7—C6—H6125 (3)
Br—C5—C4118.4 (3)C2—C7—H7119 (2)
Br—C5—C6121.1 (3)C6—C7—H7120 (2)
C4—C5—C6120.5 (4)
O—C1—C2—C3151.4 (2)C3—C2—C7—C60.0 (5)
O—C1—C2—C723.9 (3)C2—C3—C4—C51.6 (5)
C2i—C1—C2—C328.6 (4)C3—C4—C5—Br179.3 (3)
C2i—C1—C2—C7156.1 (3)C3—C4—C5—C61.2 (6)
C1—C2—C3—C4174.3 (3)Br—C5—C6—C7179.7 (3)
C7—C2—C3—C41.0 (5)C4—C5—C6—C70.2 (6)
C1—C2—C7—C6175.4 (3)C5—C6—C7—C20.4 (6)
Symmetry code: (i) x+1/2, y+1/2, z.
(II) 4,4'-dibromobenzophenone top
Crystal data top
C13H8Br2OF(000) = 656
Mr = 339.99Dx = 1.955 Mg m3
Orthorhombic, Ccc2Cu Kα radiation, λ = 1.54184 Å
Hall symbol: C 2 -2ycCell parameters from 25 reflections
a = 7.2242 (2) Åθ = 44.1–47.8°
b = 26.5957 (9) ŵ = 8.68 mm1
c = 6.0118 (2) ÅT = 103 K
V = 1155.06 (6) Å3Prism, colourless
Z = 40.18 × 0.14 × 0.07 mm
Data collection top
Enraf-Nonius CAD-4
diffractometer
630 reflections with I > 2σ(I)
Radiation source: fine-focused sealed tubeRint = 0.000
Graphite monochromatorθmax = 73.9°, θmin = 3.3°
ω/2θ scansh = 09
Absorption correction: analytical
(PLATON; Spek, 1998)
k = 320
Tmin = 0.349, Tmax = 0.581l = 07
713 measured reflections3 standard reflections every 60 min
649 independent reflections intensity decay: 2.2%
Refinement top
Refinement on F2Calculated w = 1/[σ2(Fo2) + (0.0211P)2 + 0.5575P]
where P = (Fo2 + 2Fc2)/3
Least-squares matrix: full(Δ/σ)max < 0.001
R[F2 > 2σ(F2)] = 0.019Δρmax = 0.62 e Å3
wR(F2) = 0.053Δρmin = 0.33 e Å3
S = 1.16Extinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
649 reflectionsExtinction coefficient: 0.00057 (8)
91 parametersAbsolute structure: Flack (1983)
1 restraintAbsolute structure parameter: 0.00 (4)
All H-atom parameters refined
Crystal data top
C13H8Br2OV = 1155.06 (6) Å3
Mr = 339.99Z = 4
Orthorhombic, Ccc2Cu Kα radiation
a = 7.2242 (2) ŵ = 8.68 mm1
b = 26.5957 (9) ÅT = 103 K
c = 6.0118 (2) Å0.18 × 0.14 × 0.07 mm
Data collection top
Enraf-Nonius CAD-4
diffractometer
630 reflections with I > 2σ(I)
Absorption correction: analytical
(PLATON; Spek, 1998)
Rint = 0.000
Tmin = 0.349, Tmax = 0.5813 standard reflections every 60 min
713 measured reflections intensity decay: 2.2%
649 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.019All H-atom parameters refined
wR(F2) = 0.053Δρmax = 0.62 e Å3
S = 1.16Δρmin = 0.33 e Å3
649 reflectionsAbsolute structure: Flack (1983)
91 parametersAbsolute structure parameter: 0.00 (4)
1 restraint
Special details top

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All e.s.d.'s are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

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
xyzUiso*/Ueq
Br0.27716 (4)0.04333 (1)0.44883 (10)0.0244 (1)
O0.250000.250001.1119 (7)0.0221 (10)
C10.250000.250000.9079 (8)0.0115 (13)
C20.2474 (4)0.20127 (12)0.7862 (5)0.0121 (8)
C30.3249 (4)0.19550 (11)0.5750 (4)0.0118 (8)
C40.3352 (4)0.14839 (10)0.4761 (5)0.0126 (7)
C50.2638 (4)0.10675 (13)0.5886 (6)0.0154 (9)
C60.1842 (5)0.11163 (12)0.7985 (5)0.0176 (8)
C70.1774 (5)0.15871 (14)0.8967 (4)0.0153 (9)
H30.364 (5)0.2224 (12)0.506 (6)0.014 (9)*
H40.380 (7)0.1439 (14)0.329 (7)0.031 (12)*
H60.140 (7)0.0844 (16)0.860 (7)0.035 (12)*
H70.129 (6)0.1615 (16)1.042 (6)0.019 (11)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br0.0281 (2)0.0137 (2)0.0313 (2)0.0011 (1)0.0001 (3)0.0032 (2)
O0.0300 (17)0.028 (2)0.0082 (16)0.0067 (14)0.00000.0000
C10.0105 (18)0.015 (2)0.009 (3)0.0034 (14)0.00000.0000
C20.0079 (11)0.0167 (15)0.0117 (14)0.0021 (11)0.0023 (10)0.0018 (13)
C30.0084 (12)0.0153 (12)0.0117 (15)0.0015 (11)0.0007 (11)0.0031 (11)
C40.0116 (11)0.0156 (11)0.0107 (16)0.0020 (9)0.0013 (12)0.0000 (15)
C50.0126 (13)0.0133 (15)0.0202 (19)0.0010 (10)0.0036 (11)0.0013 (14)
C60.0141 (12)0.0184 (14)0.0202 (15)0.0001 (12)0.0006 (13)0.0055 (13)
C70.0133 (14)0.0217 (16)0.0108 (16)0.0022 (13)0.0017 (10)0.0045 (11)
Geometric parameters (Å, º) top
Br—C51.887 (4)C5—C61.393 (5)
O—C11.226 (6)C6—C71.385 (5)
C1—C21.488 (4)C3—H30.87 (3)
C2—C31.396 (4)C4—H40.95 (4)
C2—C71.407 (5)C6—H60.87 (4)
C3—C41.389 (4)C7—H70.94 (4)
C4—C51.396 (4)
O—C1—C2119.4 (2)C5—C6—C7119.0 (3)
O—C1—C2i119.4 (2)C2—C7—C6120.9 (3)
C2—C1—C2i121.1 (4)C2—C3—H3118 (2)
C1—C2—C3122.5 (3)C4—C3—H3121 (2)
C1—C2—C7118.2 (3)C3—C4—H4122 (2)
C3—C2—C7119.0 (3)C5—C4—H4119 (2)
C2—C3—C4120.7 (3)C5—C6—H6117 (3)
C3—C4—C5119.2 (3)C7—C6—H6124 (3)
Br—C5—C4118.3 (2)C2—C7—H7120 (3)
Br—C5—C6120.5 (3)C6—C7—H7119 (3)
C4—C5—C6121.2 (3)
O—C1—C2—C3151.5 (2)C3—C2—C7—C60.2 (5)
O—C1—C2—C723.3 (3)C2—C3—C4—C51.2 (4)
C2i—C1—C2—C328.5 (3)C3—C4—C5—Br179.3 (2)
C2i—C1—C2—C7156.7 (3)C3—C4—C5—C60.6 (5)
C1—C2—C3—C4173.9 (3)Br—C5—C6—C7179.7 (3)
C7—C2—C3—C40.8 (4)C4—C5—C6—C70.4 (5)
C1—C2—C7—C6175.1 (3)C5—C6—C7—C20.8 (5)
Symmetry code: (i) x+1/2, y+1/2, z.

Experimental details

(I)(II)
Crystal data
Chemical formulaC13H8Br2OC13H8Br2O
Mr339.99339.99
Crystal system, space groupOrthorhombic, Ccc2Orthorhombic, Ccc2
Temperature (K)293103
a, b, c (Å)7.3969 (4), 26.7030 (9), 6.0594 (3)7.2242 (2), 26.5957 (9), 6.0118 (2)
V3)1196.85 (10)1155.06 (6)
Z44
Radiation typeCu KαCu Kα
µ (mm1)8.388.68
Crystal size (mm)0.18 × 0.14 × 0.070.18 × 0.14 × 0.07
Data collection
DiffractometerEnraf-Nonius CAD-4
diffractometer
Enraf-Nonius CAD-4
diffractometer
Absorption correctionAnalytical
(PLATON; Spek, 1998)
Analytical
(PLATON; Spek, 1998)
Tmin, Tmax0.386, 0.5910.349, 0.581
No. of measured, independent and
observed [I > 2σ(I)] reflections
744, 679, 581 713, 649, 630
Rint0.0000.000
(sin θ/λ)max1)0.6240.623
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.022, 0.066, 1.05 0.019, 0.053, 1.16
No. of reflections679649
No. of parameters9191
No. of restraints11
H-atom treatmentAll H-atom parameters refinedAll H-atom parameters refined
Δρmax, Δρmin (e Å3)0.24, 0.250.62, 0.33
Absolute structureFlack (1983)Flack (1983)
Absolute structure parameter0.02 (4)0.00 (4)

Computer programs: CAD-4 EXPRESS (Enraf-Nonius, 1992), CAD-4 EXPRESS (Enraf Nonius, 1992), CAD-4 EXPRESS and CELDIM routine, HELENA (Spek, 1997), SIR97 (Altomare et al., 1996), SHELXL97 (Sheldrick, 1997), PLATON (Spek, 1998), PLATON.

 

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