organic compounds
2-Bromo-5-fluorobenzaldehyde
aDepartment of Chemistry, Vassar College, Poughkeepsie, NY 12604, USA
*Correspondence e-mail: jotanski@vassar.edu
In the title compound, C7H4BrFO, the benzaldehyde O atom is found to be trans to the 2-bromo substituent. In the crystal, short Br⋯F interactions between the bromine and fluorine substituents are observed at distances of 3.1878 (14), 3.3641 (13) and 3.3675 (14) Å. Offset face-to-face π-stacking interactions are also observed for both of the independent molecules in the running parallel to the crystallographic b axis, characterized by centroid–centroid distances of 3.8699 (2) and 3.8699 (2) Å.
Related literature
For information on the synthesis of 2-bromo-5-fluorobenzaldehyde, see: Dubost et al. (2011). For vibrational spectroscopic analysis and ab initio structure calculations on 2-bromo-5-fluorobenzaldehyde, see: Hiremath & Sundius (2009). For the use of 2-bromo-5-fluorobenzaldehyde in organic synthesis of biologically active compounds, see: Chen et al. (2013). For additional information on halogenated aromatic in crystal structures, see: Byrn et al. (1993); Moorthy et al. (2003). For information on halogen–halogen interactions in crystal structures, see: Pedireddi et al. (1994).
Experimental
Crystal data
|
Data collection: APEX2 (Bruker, 2007); cell SAINT (Bruker, 2007); data reduction: SAINT; 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, OLEX2 (Dolomanov et al., 2009) and Mercury (Macrae et al., 2006).
Supporting information
10.1107/S1600536813018783/jj2171sup1.cif
contains datablocks I, New_Global_Publ_Block. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536813018783/jj2171Isup2.hkl
Supporting information file. DOI: 10.1107/S1600536813018783/jj2171Isup3.cml
2-bromo-5-fluorobenzaldehyde was purchased from Aldrich Chemical Company, USA, and was recrystallized from chloroform.
All non-hydrogen atoms were refined anisotropically. Hydrogen atoms on carbon were included in calculated positions and refined using a riding model at C–H = 0.95 Å and Uiso(H) = 1.2 × Ueq(C) of the aryl C-atoms. The extinction parameter (EXTI) refined to zero and was removed from the refinement.
Data collection: APEX2 (Bruker, 2007); cell
SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 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), OLEX2 (Dolomanov et al., 2009) and Mercury (Macrae et al., 2006).C7H4BrFO | F(000) = 784 |
Mr = 203.01 | Dx = 2.019 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 9913 reflections |
a = 15.3593 (6) Å | θ = 2.6–30.5° |
b = 3.8699 (2) Å | µ = 6.09 mm−1 |
c = 23.4189 (9) Å | T = 125 K |
β = 106.330 (1)° | Plate, colourless |
V = 1335.84 (10) Å3 | 0.36 × 0.16 × 0.03 mm |
Z = 8 |
Bruker APEXII CCD diffractometer | 4080 independent reflections |
Radiation source: fine-focus sealed tube | 3468 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.033 |
ϕ and ω scans | θmax = 30.5°, θmin = 1.8° |
Absorption correction: multi-scan (SADABS; Bruker, 2007) | h = −21→21 |
Tmin = 0.218, Tmax = 0.838 | k = −5→5 |
20203 measured reflections | l = −33→33 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.027 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.068 | H-atom parameters constrained |
S = 1.03 | w = 1/[σ2(Fo2) + (0.0289P)2 + 1.4137P] where P = (Fo2 + 2Fc2)/3 |
4080 reflections | (Δ/σ)max = 0.001 |
181 parameters | Δρmax = 1.83 e Å−3 |
0 restraints | Δρmin = −0.82 e Å−3 |
C7H4BrFO | V = 1335.84 (10) Å3 |
Mr = 203.01 | Z = 8 |
Monoclinic, P21/c | Mo Kα radiation |
a = 15.3593 (6) Å | µ = 6.09 mm−1 |
b = 3.8699 (2) Å | T = 125 K |
c = 23.4189 (9) Å | 0.36 × 0.16 × 0.03 mm |
β = 106.330 (1)° |
Bruker APEXII CCD diffractometer | 4080 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2007) | 3468 reflections with I > 2σ(I) |
Tmin = 0.218, Tmax = 0.838 | Rint = 0.033 |
20203 measured reflections |
R[F2 > 2σ(F2)] = 0.027 | 0 restraints |
wR(F2) = 0.068 | H-atom parameters constrained |
S = 1.03 | Δρmax = 1.83 e Å−3 |
4080 reflections | Δρmin = −0.82 e Å−3 |
181 parameters |
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 | ||
Br1 | 0.080111 (13) | 0.22202 (5) | 0.216581 (8) | 0.01891 (6) | |
Br2 | 0.462736 (14) | 0.76345 (5) | 0.083534 (10) | 0.02508 (6) | |
F1 | 0.25127 (9) | 0.6309 (4) | 0.02624 (6) | 0.0291 (3) | |
F2 | 0.85470 (8) | 1.1648 (4) | 0.15460 (6) | 0.0280 (3) | |
O1 | −0.05661 (10) | 0.8333 (4) | 0.05688 (7) | 0.0262 (3) | |
O2 | 0.60148 (11) | 1.3284 (5) | 0.24807 (7) | 0.0319 (4) | |
C1 | −0.01416 (13) | 0.6545 (5) | 0.09806 (9) | 0.0192 (4) | |
H1A | −0.0436 | 0.5795 | 0.1265 | 0.023* | |
C2 | 0.08121 (12) | 0.5479 (5) | 0.10601 (8) | 0.0154 (3) | |
C3 | 0.13221 (13) | 0.3679 (5) | 0.15590 (8) | 0.0156 (3) | |
C4 | 0.22246 (13) | 0.2828 (5) | 0.16300 (9) | 0.0194 (4) | |
H4A | 0.2564 | 0.1646 | 0.1977 | 0.023* | |
C5 | 0.26256 (14) | 0.3727 (5) | 0.11871 (9) | 0.0219 (4) | |
H5A | 0.3241 | 0.3164 | 0.1225 | 0.026* | |
C6 | 0.21117 (14) | 0.5449 (5) | 0.06927 (9) | 0.0206 (4) | |
C7 | 0.12254 (13) | 0.6377 (5) | 0.06165 (8) | 0.0181 (4) | |
H7A | 0.0898 | 0.7601 | 0.0271 | 0.022* | |
C8 | 0.57143 (14) | 1.1450 (6) | 0.20481 (9) | 0.0226 (4) | |
H8A | 0.5118 | 1.0545 | 0.1978 | 0.027* | |
C9 | 0.62435 (13) | 1.0572 (5) | 0.16259 (8) | 0.0166 (3) | |
C10 | 0.58708 (13) | 0.8909 (5) | 0.10820 (9) | 0.0176 (3) | |
C11 | 0.63924 (15) | 0.8169 (5) | 0.06990 (9) | 0.0217 (4) | |
H11A | 0.6125 | 0.7055 | 0.0330 | 0.026* | |
C12 | 0.73049 (14) | 0.9061 (5) | 0.08565 (9) | 0.0218 (4) | |
H12A | 0.7673 | 0.8545 | 0.0602 | 0.026* | |
C13 | 0.76605 (13) | 1.0719 (5) | 0.13929 (9) | 0.0191 (4) | |
C14 | 0.71611 (13) | 1.1487 (5) | 0.17800 (8) | 0.0181 (3) | |
H14A | 0.7435 | 1.2621 | 0.2146 | 0.022* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Br1 | 0.02187 (10) | 0.01889 (9) | 0.01725 (9) | −0.00061 (7) | 0.00756 (7) | 0.00286 (7) |
Br2 | 0.01723 (10) | 0.02099 (11) | 0.03344 (12) | −0.00366 (7) | 0.00124 (8) | −0.00262 (8) |
F1 | 0.0273 (7) | 0.0388 (7) | 0.0277 (6) | −0.0023 (6) | 0.0182 (5) | 0.0033 (6) |
F2 | 0.0148 (6) | 0.0395 (7) | 0.0314 (7) | −0.0053 (5) | 0.0095 (5) | 0.0010 (6) |
O1 | 0.0215 (7) | 0.0328 (8) | 0.0237 (7) | 0.0061 (6) | 0.0051 (6) | 0.0075 (6) |
O2 | 0.0253 (8) | 0.0419 (9) | 0.0317 (9) | −0.0034 (7) | 0.0130 (7) | −0.0137 (7) |
C1 | 0.0164 (8) | 0.0208 (9) | 0.0212 (9) | −0.0006 (7) | 0.0064 (7) | 0.0012 (7) |
C2 | 0.0140 (8) | 0.0145 (8) | 0.0174 (8) | −0.0019 (6) | 0.0038 (7) | −0.0007 (6) |
C3 | 0.0175 (8) | 0.0134 (8) | 0.0168 (8) | −0.0017 (6) | 0.0062 (7) | −0.0009 (6) |
C4 | 0.0171 (9) | 0.0176 (9) | 0.0224 (9) | 0.0011 (7) | 0.0039 (7) | 0.0010 (7) |
C5 | 0.0160 (9) | 0.0207 (9) | 0.0298 (10) | 0.0002 (7) | 0.0080 (8) | −0.0013 (8) |
C6 | 0.0222 (10) | 0.0216 (9) | 0.0219 (9) | −0.0034 (7) | 0.0126 (8) | −0.0017 (7) |
C7 | 0.0196 (9) | 0.0179 (8) | 0.0164 (8) | −0.0032 (7) | 0.0044 (7) | −0.0011 (7) |
C8 | 0.0164 (9) | 0.0259 (10) | 0.0267 (10) | −0.0005 (8) | 0.0081 (8) | −0.0012 (8) |
C9 | 0.0152 (8) | 0.0151 (8) | 0.0206 (9) | 0.0006 (6) | 0.0066 (7) | 0.0014 (7) |
C10 | 0.0145 (8) | 0.0144 (8) | 0.0221 (9) | 0.0000 (6) | 0.0023 (7) | 0.0016 (7) |
C11 | 0.0260 (10) | 0.0190 (9) | 0.0190 (9) | 0.0016 (8) | 0.0047 (8) | 0.0007 (7) |
C12 | 0.0250 (10) | 0.0224 (9) | 0.0212 (9) | 0.0026 (8) | 0.0115 (8) | 0.0024 (7) |
C13 | 0.0143 (9) | 0.0214 (9) | 0.0221 (9) | −0.0001 (7) | 0.0061 (7) | 0.0038 (7) |
C14 | 0.0158 (8) | 0.0187 (8) | 0.0196 (9) | −0.0017 (7) | 0.0048 (7) | 0.0007 (7) |
Br1—C3 | 1.9021 (18) | C5—C6 | 1.376 (3) |
Br2—C10 | 1.8985 (19) | C5—H5A | 0.9500 |
Br2—F1 | 3.1878 (14) | C6—C7 | 1.370 (3) |
F1—C6 | 1.362 (2) | C7—H7A | 0.9500 |
F2—C13 | 1.355 (2) | C8—C9 | 1.485 (3) |
F2—Br1i | 3.3641 (13) | C8—H8A | 0.9500 |
F2—Br1ii | 3.3675 (14) | C9—C10 | 1.398 (3) |
O1—C1 | 1.217 (3) | C9—C14 | 1.399 (3) |
O2—C8 | 1.217 (3) | C10—C11 | 1.390 (3) |
C1—C2 | 1.482 (3) | C11—C12 | 1.389 (3) |
C1—H1A | 0.9500 | C11—H11A | 0.9500 |
C2—C3 | 1.396 (3) | C12—C13 | 1.379 (3) |
C2—C7 | 1.405 (3) | C12—H12A | 0.9500 |
C3—C4 | 1.389 (3) | C13—C14 | 1.374 (3) |
C4—C5 | 1.391 (3) | C14—H14A | 0.9500 |
C4—H4A | 0.9500 | ||
C10—Br2—F1 | 171.36 (6) | C6—C7—H7A | 120.7 |
C6—F1—Br2 | 110.32 (11) | C2—C7—H7A | 120.7 |
C13—F2—Br1i | 165.26 (12) | O2—C8—C9 | 122.51 (19) |
C13—F2—Br1ii | 97.22 (10) | O2—C8—H8A | 118.7 |
Br1i—F2—Br1ii | 68.67 (3) | C9—C8—H8A | 118.7 |
O1—C1—C2 | 123.25 (18) | C10—C9—C14 | 118.44 (17) |
O1—C1—H1A | 118.4 | C10—C9—C8 | 123.47 (17) |
C2—C1—H1A | 118.4 | C14—C9—C8 | 118.09 (17) |
C3—C2—C7 | 118.59 (17) | C11—C10—C9 | 121.34 (18) |
C3—C2—C1 | 123.09 (16) | C11—C10—Br2 | 117.59 (15) |
C7—C2—C1 | 118.31 (17) | C9—C10—Br2 | 121.06 (14) |
C4—C3—C2 | 121.66 (17) | C12—C11—C10 | 119.94 (19) |
C4—C3—Br1 | 117.11 (14) | C12—C11—H11A | 120.0 |
C2—C3—Br1 | 121.23 (14) | C10—C11—H11A | 120.0 |
C3—C4—C5 | 119.19 (18) | C13—C12—C11 | 117.98 (18) |
C3—C4—H4A | 120.4 | C13—C12—H12A | 121.0 |
C5—C4—H4A | 120.4 | C11—C12—H12A | 121.0 |
C6—C5—C4 | 118.62 (18) | F2—C13—C14 | 118.27 (18) |
C6—C5—H5A | 120.7 | F2—C13—C12 | 118.38 (17) |
C4—C5—H5A | 120.7 | C14—C13—C12 | 123.35 (18) |
F1—C6—C7 | 118.63 (18) | C13—C14—C9 | 118.94 (18) |
F1—C6—C5 | 117.97 (18) | C13—C14—H14A | 120.5 |
C7—C6—C5 | 123.39 (18) | C9—C14—H14A | 120.5 |
C6—C7—C2 | 118.54 (18) | ||
O1—C1—C2—C3 | 174.3 (2) | O2—C8—C9—C14 | 9.3 (3) |
O1—C1—C2—C7 | −4.5 (3) | C14—C9—C10—C11 | −0.1 (3) |
C7—C2—C3—C4 | 1.3 (3) | C8—C9—C10—C11 | 179.40 (19) |
C1—C2—C3—C4 | −177.61 (18) | C14—C9—C10—Br2 | −179.19 (14) |
C7—C2—C3—Br1 | −177.71 (14) | C8—C9—C10—Br2 | 0.3 (3) |
C1—C2—C3—Br1 | 3.4 (3) | C9—C10—C11—C12 | 0.5 (3) |
C2—C3—C4—C5 | −1.4 (3) | Br2—C10—C11—C12 | 179.70 (15) |
Br1—C3—C4—C5 | 177.64 (15) | C10—C11—C12—C13 | −0.9 (3) |
C3—C4—C5—C6 | 0.3 (3) | Br1i—F2—C13—C14 | 74.6 (5) |
Br2—F1—C6—C7 | 148.75 (15) | Br1ii—F2—C13—C14 | 58.25 (18) |
Br2—F1—C6—C5 | −30.4 (2) | Br1i—F2—C13—C12 | −105.5 (4) |
C4—C5—C6—F1 | −179.91 (18) | Br1ii—F2—C13—C12 | −121.91 (16) |
C4—C5—C6—C7 | 1.0 (3) | C11—C12—C13—F2 | −178.98 (18) |
F1—C6—C7—C2 | 179.81 (17) | C11—C12—C13—C14 | 0.8 (3) |
C5—C6—C7—C2 | −1.1 (3) | F2—C13—C14—C9 | 179.45 (17) |
C3—C2—C7—C6 | 0.0 (3) | C12—C13—C14—C9 | −0.4 (3) |
C1—C2—C7—C6 | 178.90 (18) | C10—C9—C14—C13 | 0.0 (3) |
O2—C8—C9—C10 | −170.2 (2) | C8—C9—C14—C13 | −179.52 (18) |
Symmetry codes: (i) x+1, y+1, z; (ii) −x+1, y+1/2, −z+1/2. |
Experimental details
Crystal data | |
Chemical formula | C7H4BrFO |
Mr | 203.01 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 125 |
a, b, c (Å) | 15.3593 (6), 3.8699 (2), 23.4189 (9) |
β (°) | 106.330 (1) |
V (Å3) | 1335.84 (10) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 6.09 |
Crystal size (mm) | 0.36 × 0.16 × 0.03 |
Data collection | |
Diffractometer | Bruker APEXII CCD diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 2007) |
Tmin, Tmax | 0.218, 0.838 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 20203, 4080, 3468 |
Rint | 0.033 |
(sin θ/λ)max (Å−1) | 0.715 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.027, 0.068, 1.03 |
No. of reflections | 4080 |
No. of parameters | 181 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 1.83, −0.82 |
Computer programs: APEX2 (Bruker, 2007), SAINT (Bruker, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008), OLEX2 (Dolomanov et al., 2009) and Mercury (Macrae et al., 2006).
Acknowledgements
This work was supported by Vassar College. X-ray facilities were provided by the US National Science Foundation (grant No. 0521237 to JMT).
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.
Ab initio electronic structure calculations have predicted that the lower energy conformer of 2-bromo-5-fluorobenzaldehyde is the one in which the benzaldehyde oxygen is trans to the 2-bromo substituent (Hiremath & Sundius, 2009). The crystal structure of 2-bromo-5-fluorobenzaldehyde reported here is consistent with this finding. The compound may be synthesized by selective ortho-bromination of the appropriate benzaldoxime (Dubost et al., 2011). The substance has found laboratory application in the synthesis of quinazolinones which are known to show antitumor activity (Chen et al., 2013). Crystal structures of halogenated aromatic aldehydes have been previously reported (Moorthy et al., 2003), and they are also known in clathrates (Byrn et al.,1993).
The titular compound crystallizes with two molecules of 2-bromo-5-fluorobenzaldehyde in the asymmetric unit (Fig. 1). The benzaldehyde oxygen is trans to the 2-bromo substituent, with O1—C1—C2—C3 and O2—C8—C9—C10 torsional angles of 174.3 (2)° and 170.2 (2)°, respectively. Several short intermolecuar halogen-halogen interactions can be seen in the structure between fluorine and bromine atoms. Within the asymmetric unit, the F1···Br2 distance of 3.1878 (14) Å is significantly shorter than the sum of the van der Waals radii of bromine and fluorine, 3.40 Å (Pedireddi et al., 1994). Somewhat longer, the F2···Br1i distance 3.3641 (13) and F2···Br1ii distance 3.3675 (14) Å are about the same as the sum of the van der Waals radii of fluorine and bromine (Fig 2.)
The aromatic compound packs in the solid state with an offset face-to-face π-stacking motif parallel to the crystallographic b-axis (Fig 2.). Each independent molecule in the asymmetric unit π-stacks with itself. This π-stacking motif is characterized by a centroid-to-centroid distance of 3.8699 (2) Å, centroid-to-plance distance of 3.371 (2) Å, and ring-offset of 1.901 (3) Å for molecule 1 and centroid-to-centroid distance of 3.8699 (2) Å, centroid-to-plance distance of 3.431 (2) Å, and ring-offset of 1.790 (3) Å for molecule 2.