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ISSN: 2056-9890

2,5-Di­bromo­terephthalic acid dihydrate

aDepartment of Applied Chemistry, College of Science, Nanjing University of Technology, Nanjing 210009, People's Republic of China
*Correspondence e-mail: zhuhj@njut.edu.cn

(Received 16 May 2008; accepted 24 August 2008; online 30 August 2008)

The asymmetric unit of the title compound, C8H4Br2O4·2H2O, contains one half-mol­ecule of 2,5-dibromo­terephthalic acid (DBTA) and one water mol­ecule. The DBTA mol­ecule is centrosymmetric. In the crystal structure, inter­molecular O—H⋯O hydrogen bonds link the mol­ecules, forming a three-dimensional framework.

Related literature

For general background, see: Yao & Tour (1999[Yao, Y. X. & Tour, J. M. (1999). Macromolecules, 32, 2455-2461.]). For a related structure, see: Singh & Bedi (1957[Singh, T. & Bedi, S. N. (1957). J. Indian Chem. Soc. 34, 321-323.]).

[Scheme 1]

Experimental

Crystal data
  • C8H4Br2O4·2H2O

  • Mr = 359.94

  • Monoclinic, P 21 /c

  • a = 10.670 (2) Å

  • b = 7.413 (1) Å

  • c = 7.074 (1) Å

  • β = 92.74 (3)°

  • V = 558.89 (15) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 7.26 mm−1

  • T = 293 (2) K

  • 0.10 × 0.10 × 0.08 mm

Data collection
  • Enraf–Nonius CAD-4 diffractometer

  • Absorption correction: ψ scan (North et al., 1968[North, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351-359.]) Tmin = 0.530, Tmax = 0.594 (expected range = 0.499–0.559)

  • 1003 measured reflections

  • 1003 independent reflections

  • 763 reflections with I > 2σ(I)

  • 3 standard reflections every 200 reflections intensity decay: none

Refinement
  • R[F2 > 2σ(F2)] = 0.048

  • wR(F2) = 0.117

  • S = 1.05

  • 1003 reflections

  • 67 parameters

  • 21 restraints

  • H-atom parameters constrained

  • Δρmax = 0.55 e Å−3

  • Δρmin = −0.70 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
OW—HWA⋯O1i 0.85 2.11 2.903 (9) 155
OW—HWB⋯O1ii 0.85 2.22 2.944 (9) 142
O2—H2A⋯OW 0.82 1.75 2.566 (8) 177
Symmetry codes: (i) -x, -y, -z+1; (ii) [-x, y-{\script{1\over 2}}, -z+{\script{3\over 2}}].

Data collection: CAD-4 Software (Enraf–Nonius, 1985[Enraf-Nonius (1985). CAD-4 Software. Enraf-Nonius, Delft, The Netherlands.]); cell refinement: CAD-4 Software; data reduction: XCAD4 (Harms & Wocadlo, 1995[Harms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany.]); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); software used to prepare material for publication: SHELXTL.

Supporting information


Comment top

2,5-Dibromoterephthalic acid (DBTA) is an important intermediate in the preparation of flame-retardant polymers (Yao et al., 1999). We report herein the crystal structure of the title compound (I).

The asymmetric unit of I (Fig. 1), contains one half of a molecule of 2,5-dibromoterephthalic acid (DBTA), which is related to the other half by a center of symmetry, and one water molecule. Three neighbouring DBTA molecules are linked through one water molecule by intermolecular O—H···O hydrogen bonds, to form a three dimensional framework.

Related literature top

For general background, see: Yao & Tour (1999). For a related structure, see: Singh & Bedi (1957).

Experimental top

The title compound was prepared according to the method described by Singh & Bedi (1957). Crystals of (I) suitable for X-ray analysis were obtained by dissolving DBTA (2.0 g) in water (80 ml) and evaporating slowly at room temperature for about 15 d.

Refinement top

Anisotropic parameters of the C atoms in the phenyl ring were restrained to have equal components and approximately isotropic behavior. H atoms were positioned geometrically, with O—H = 0.82 (for OH) and 0.85 (for H2O) and C—H = 0.93 and 0.96 Å for aromatic and methyl H, respectively, and constrained to ride on their parent atoms, with Uiso(H) = xUeq(C/O), where x = 1.2 for aromatic H and x = 1.5 for other H.

Computing details top

Data collection: CAD-4 Software (Enraf–Nonius, 1985); cell refinement: CAD-4 Software (Enraf–Nonius, 1985); data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXS97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I), showing the atom labelling scheme. Anisotropic displacement parameters are shown at the 50% probability level.
2,5-Dibromoterephthalic acid dihydrate top
Crystal data top
C8H4Br2O4·2H2OF(000) = 348
Mr = 359.94Dx = 2.139 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
a = 10.670 (2) ÅCell parameters from 25 reflections
b = 7.413 (1) Åθ = 10–13°
c = 7.074 (1) ŵ = 7.26 mm1
β = 92.74 (3)°T = 293 K
V = 558.89 (15) Å3Block, colorless
Z = 20.10 × 0.10 × 0.08 mm
Data collection top
Enraf–Nonius CAD-4
diffractometer
763 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.000
Graphite monochromatorθmax = 25.2°, θmin = 1.9°
ω/2θ scansh = 1212
Absorption correction: ψ scan
(North et al., 1968)
k = 08
Tmin = 0.530, Tmax = 0.594l = 08
1003 measured reflections3 standard reflections every 200 reflections
1003 independent reflections intensity decay: none
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.048Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.117H-atom parameters constrained
S = 1.05 w = 1/[σ2(Fo2) + (0.06P)2 + 1.5P]
where P = (Fo2 + 2Fc2)/3
1003 reflections(Δ/σ)max < 0.001
67 parametersΔρmax = 0.55 e Å3
21 restraintsΔρmin = 0.70 e Å3
Crystal data top
C8H4Br2O4·2H2OV = 558.89 (15) Å3
Mr = 359.94Z = 2
Monoclinic, P21/cMo Kα radiation
a = 10.670 (2) ŵ = 7.26 mm1
b = 7.413 (1) ÅT = 293 K
c = 7.074 (1) Å0.10 × 0.10 × 0.08 mm
β = 92.74 (3)°
Data collection top
Enraf–Nonius CAD-4
diffractometer
763 reflections with I > 2σ(I)
Absorption correction: ψ scan
(North et al., 1968)
Rint = 0.000
Tmin = 0.530, Tmax = 0.5943 standard reflections every 200 reflections
1003 measured reflections intensity decay: none
1003 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.04821 restraints
wR(F2) = 0.117H-atom parameters constrained
S = 1.05Δρmax = 0.55 e Å3
1003 reflectionsΔρmin = 0.70 e Å3
67 parameters
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
xyzUiso*/Ueq
Br0.31754 (7)0.35260 (9)0.52687 (10)0.0366 (3)
OW0.0069 (5)0.2828 (11)0.7105 (11)0.093 (3)
HWA0.06080.20280.67800.111*
HWB0.02990.37860.76510.111*
O10.1532 (5)0.0220 (6)0.5124 (8)0.0495 (14)
O20.2259 (5)0.2252 (7)0.6570 (9)0.0554 (15)
H2A0.15150.24020.67670.083*
C10.5431 (6)0.1725 (10)0.4729 (9)0.034
H1A0.57250.28850.45180.040*
C20.4182 (6)0.1457 (8)0.5085 (9)0.0276 (13)
C30.3736 (6)0.0245 (8)0.5317 (8)0.0255 (13)
C40.2396 (6)0.0748 (9)0.5662 (9)0.0314 (15)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br0.0487 (4)0.0111 (4)0.0496 (5)0.0050 (3)0.0007 (3)0.0002 (3)
OW0.030 (3)0.111 (6)0.139 (7)0.008 (3)0.013 (3)0.073 (5)
O10.045 (3)0.016 (3)0.087 (4)0.004 (2)0.002 (3)0.015 (3)
O20.051 (3)0.028 (3)0.087 (4)0.006 (3)0.004 (3)0.029 (3)
C10.0340.0340.0340.0000.0020.000
C20.043 (3)0.009 (3)0.030 (3)0.002 (3)0.009 (3)0.000 (3)
C30.038 (3)0.013 (3)0.025 (3)0.002 (3)0.003 (2)0.004 (3)
C40.035 (3)0.022 (3)0.038 (4)0.003 (3)0.004 (3)0.005 (3)
Geometric parameters (Å, º) top
Br—C21.880 (6)C1—C21.383 (8)
OW—HWA0.8500C1—C3i1.413 (9)
OW—HWB0.8500C1—H1A0.9300
O1—C41.215 (8)C2—C31.361 (8)
O2—C41.299 (8)C3—C1i1.413 (9)
O2—H2A0.8200C3—C41.508 (9)
HWA—OW—HWB120.0C1—C2—Br117.0 (5)
C4—O2—H2A109.5C2—C3—C1i119.5 (6)
C2—C1—C3i120.4 (6)C2—C3—C4126.0 (6)
C2—C1—H1A119.8C1i—C3—C4114.5 (5)
C3i—C1—H1A119.8O1—C4—O2124.1 (6)
C3—C2—C1120.1 (6)O1—C4—C3121.0 (6)
C3—C2—Br122.9 (5)O2—C4—C3115.0 (6)
C3i—C1—C2—C32.7 (10)Br—C2—C3—C42.8 (9)
C3i—C1—C2—Br176.2 (5)C2—C3—C4—O126.1 (10)
C1—C2—C3—C1i2.7 (10)C1i—C3—C4—O1154.9 (6)
Br—C2—C3—C1i176.2 (5)C2—C3—C4—O2153.4 (7)
C1—C2—C3—C4178.3 (6)C1i—C3—C4—O225.6 (8)
Symmetry code: (i) x+1, y, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
OW—HWA···O1ii0.852.112.903 (9)155
OW—HWB···O1iii0.852.222.944 (9)142
O2—H2A···OW0.821.752.566 (8)177
Symmetry codes: (ii) x, y, z+1; (iii) x, y1/2, z+3/2.

Experimental details

Crystal data
Chemical formulaC8H4Br2O4·2H2O
Mr359.94
Crystal system, space groupMonoclinic, P21/c
Temperature (K)293
a, b, c (Å)10.670 (2), 7.413 (1), 7.074 (1)
β (°) 92.74 (3)
V3)558.89 (15)
Z2
Radiation typeMo Kα
µ (mm1)7.26
Crystal size (mm)0.10 × 0.10 × 0.08
Data collection
DiffractometerEnraf–Nonius CAD-4
diffractometer
Absorption correctionψ scan
(North et al., 1968)
Tmin, Tmax0.530, 0.594
No. of measured, independent and
observed [I > 2σ(I)] reflections
1003, 1003, 763
Rint0.000
(sin θ/λ)max1)0.599
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.048, 0.117, 1.05
No. of reflections1003
No. of parameters67
No. of restraints21
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.55, 0.70

Computer programs: CAD-4 Software (Enraf–Nonius, 1985), XCAD4 (Harms & Wocadlo, 1995), SHELXS97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Selected geometric parameters (Å, º) top
Br—C21.880 (6)O2—C41.299 (8)
O1—C41.215 (8)
C3—C2—Br122.9 (5)O1—C4—C3121.0 (6)
C1—C2—Br117.0 (5)O2—C4—C3115.0 (6)
O1—C4—O2124.1 (6)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
OW—HWA···O1i0.85002.11002.903 (9)155.00
OW—HWB···O1ii0.85002.22002.944 (9)142.00
O2—H2A···OW0.82001.75002.566 (8)177.00
Symmetry codes: (i) x, y, z+1; (ii) x, y1/2, z+3/2.
 

Acknowledgements

The authors thank the Center of Testing and Analysis, Nanjing University, for support.

References

First citationEnraf–Nonius (1985). CAD-4 Software. Enraf–Nonius, Delft, The Netherlands.  Google Scholar
First citationHarms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany.  Google Scholar
First citationNorth, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351–359.  CrossRef IUCr Journals Web of Science Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSingh, T. & Bedi, S. N. (1957). J. Indian Chem. Soc. 34, 321–323.  CAS Google Scholar
First citationYao, Y. X. & Tour, J. M. (1999). Macromolecules, 32, 2455–2461.  Web of Science CrossRef CAS Google Scholar

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.

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COMMUNICATIONS
ISSN: 2056-9890
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