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

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ISSN: 2056-9890

A polymorph of terephthalaldehyde

aSchool of Chemical and Materials Engineering, Huangshi Institute of Technology, Huangshi 435003, People's Republic of China
*Correspondence e-mail: chwangzg@yahoo.com.cn

(Received 15 July 2008; accepted 17 July 2008; online 23 July 2008)

A new ortho­rhom­bic polymorph of terephthalaldehyde, C8H6O2, with a melting point of 372 K, has been obtained by recrystallization from ethanol. At room temperature, the crystals transform into the well known monoclinic form, with a melting point of 389 K. The crystal structure of the monoclinic form involves C—H⋯O hydrogen bonds, but no such bonds are observed in the orthorhombic form. The molecule is planar.

Related literature

For the structure of the monoclinic polymorph, see: Britton (1998[Britton, D. (1998). J. Chem. Crystallogr. 28, 601-604.]).

[Scheme 1]

Experimental

Crystal data
  • C8H6O2

  • Mr = 134.13

  • Orthorhombic, P c a 21

  • a = 12.8811 (5) Å

  • b = 3.8933 (3) Å

  • c = 13.3202 (9) Å

  • V = 668.01 (7) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.10 mm−1

  • T = 295 (2) K

  • 0.20 × 0.10 × 0.10 mm

Data collection
  • Bruker SMART 4K CCD area-detector diffractometer

  • Absorption correction: none

  • 3959 measured reflections

  • 653 independent reflections

  • 563 reflections with I > 2σ(I)

  • Rint = 0.030

Refinement
  • R[F2 > 2σ(F2)] = 0.042

  • wR(F2) = 0.112

  • S = 1.04

  • 653 reflections

  • 91 parameters

  • 1 restraint

  • H-atom parameters constrained

  • Δρmax = 0.16 e Å−3

  • Δρmin = −0.10 e Å−3

Data collection: SMART (Bruker, 2001[Bruker (2001). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2001[Bruker (2001). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; 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

Terephthalaldehyde, (I), is a simple aromatic compound used in organic synthesis. It is known as a white substance, slightly soluble in water, with a melting point of 389 K. To the best of our knowledge, the only packing information of (I) in the solid state comes from the work of Britton (Britton, 1998), who investigated the intermolecular C—H···O arrangement in the structure of terephthalaldehyde and the crystals suitable for diffraction were obtained by recrystallization from an acetone/ethyl ether mixture.

A new polymorphic form of (I) has been obtained serendipitously during cocrystallization of pyridine and terephthalaldehyde from ethanol (Fig. 1). Flat needles which precipitated first from the solution had a melting point of 372 K and were identified as a new polymorphic form of (I) by X-ray crystallography. At room temperature, the crystals transform into the well known monoclinic form, with a melting point of 389 K. The crystal structure of the monoclinic form involves C—H···O hydrogen bonds but no such bonds are observed in the orthorhombic form (Fig. 2).

Related literature top

For a related structure, see: Britton (1998).

Experimental top

The title compound was purchased from Aldrich.

Refinement top

All H atoms were initially located in a difference Fourier map and then included with constrained bond lengths and isotropic displacement parameters: C—H=0.93Å and Uiso(H)=1.2Ueq(C) for H atoms.

Computing details top

Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT (Bruker, 2001); 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).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I) with 50% probability displacement ellipsoids (arbitrary spheres for H atoms).
[Figure 2] Fig. 2. The packing of the molecules, viewed down the b axis.
terephthalaldehyde top
Crystal data top
C8H6O2F(000) = 280
Mr = 134.13Dx = 1.334 Mg m3
Orthorhombic, Pca21Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2acCell parameters from 1070 reflections
a = 12.8811 (5) Åθ = 3.1–23.5°
b = 3.8933 (3) ŵ = 0.10 mm1
c = 13.3202 (9) ÅT = 295 K
V = 668.01 (7) Å3Block, colorless
Z = 40.20 × 0.10 × 0.10 mm
Data collection top
Bruker SMART 4K CCD area-detector
diffractometer
563 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.030
Graphite monochromatorθmax = 25.5°, θmin = 3.1°
ϕ and ω scansh = 1512
3959 measured reflectionsk = 44
653 independent reflectionsl = 1615
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)] = 0.042Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.112H-atom parameters constrained
S = 1.04 w = 1/[σ2(Fo2) + (0.0755P)2 + 0.0133P]
where P = (Fo2 + 2Fc2)/3
653 reflections(Δ/σ)max = 0.014
91 parametersΔρmax = 0.16 e Å3
1 restraintΔρmin = 0.10 e Å3
Crystal data top
C8H6O2V = 668.01 (7) Å3
Mr = 134.13Z = 4
Orthorhombic, Pca21Mo Kα radiation
a = 12.8811 (5) ŵ = 0.10 mm1
b = 3.8933 (3) ÅT = 295 K
c = 13.3202 (9) Å0.20 × 0.10 × 0.10 mm
Data collection top
Bruker SMART 4K CCD area-detector
diffractometer
563 reflections with I > 2σ(I)
3959 measured reflectionsRint = 0.030
653 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0421 restraint
wR(F2) = 0.112H-atom parameters constrained
S = 1.04Δρmax = 0.16 e Å3
653 reflectionsΔρmin = 0.10 e Å3
91 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
C10.8164 (2)0.3463 (7)0.2145 (2)0.0509 (7)
C20.9236 (2)0.3850 (7)0.2147 (3)0.0545 (7)
H20.95660.48470.15990.065*
C30.9315 (2)0.1279 (7)0.3776 (2)0.0515 (7)
C40.8239 (2)0.0894 (7)0.3770 (3)0.0547 (7)
H40.79070.01060.43160.066*
C50.7668 (2)0.1993 (6)0.2955 (3)0.0543 (7)
H50.69500.17440.29530.065*
C60.9805 (2)0.2776 (7)0.2951 (3)0.0547 (6)
H61.05230.30400.29490.066*
C70.7563 (4)0.4635 (8)0.1269 (4)0.0707 (10)
H70.79340.55470.07330.085*
C80.9916 (3)0.0084 (8)0.4657 (4)0.0627 (9)
H80.95500.08740.51900.075*
O10.6637 (2)0.4514 (7)0.1187 (3)0.0930 (10)
O21.0834 (2)0.0266 (7)0.4731 (4)0.0876 (9)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0535 (16)0.0494 (14)0.0498 (17)0.0041 (11)0.0057 (14)0.0068 (13)
C20.0564 (18)0.0551 (15)0.0520 (17)0.0022 (13)0.0123 (15)0.0015 (15)
C30.0547 (16)0.0509 (14)0.0490 (17)0.0008 (12)0.0064 (15)0.0078 (13)
C40.0593 (19)0.0573 (14)0.0476 (17)0.0067 (14)0.0140 (16)0.0002 (14)
C50.0463 (13)0.0570 (14)0.0595 (15)0.0016 (12)0.0102 (17)0.0083 (14)
C60.0448 (13)0.0582 (14)0.0610 (15)0.0003 (12)0.0043 (18)0.0008 (14)
C70.071 (2)0.077 (2)0.063 (3)0.0121 (16)0.006 (2)0.0016 (18)
C80.067 (2)0.0704 (19)0.0508 (19)0.0030 (13)0.009 (2)0.0003 (14)
O10.075 (2)0.129 (2)0.075 (2)0.0162 (14)0.0158 (19)0.0026 (18)
O20.0617 (17)0.125 (2)0.0761 (19)0.0064 (12)0.0077 (16)0.0074 (15)
Geometric parameters (Å, º) top
C1—C51.378 (4)C4—C51.379 (5)
C1—C21.389 (4)C4—H40.9300
C1—C71.473 (6)C5—H50.9300
C2—C61.363 (5)C6—H60.9300
C2—H20.9300C7—O11.199 (5)
C3—C41.393 (4)C7—H70.9300
C3—C61.395 (4)C8—O21.188 (4)
C3—C81.482 (6)C8—H80.9300
C5—C1—C2120.2 (3)C1—C5—C4119.9 (3)
C5—C1—C7120.4 (3)C1—C5—H5120.1
C2—C1—C7119.4 (3)C4—C5—H5120.1
C6—C2—C1120.2 (3)C2—C6—C3120.2 (2)
C6—C2—H2119.9C2—C6—H6119.9
C1—C2—H2119.9C3—C6—H6119.9
C4—C3—C6119.4 (3)O1—C7—C1125.6 (5)
C4—C3—C8119.4 (3)O1—C7—H7117.2
C6—C3—C8121.2 (3)C1—C7—H7117.2
C5—C4—C3120.1 (3)O2—C8—C3124.5 (4)
C5—C4—H4120.0O2—C8—H8117.7
C3—C4—H4120.0C3—C8—H8117.7
C5—C1—C2—C60.1 (4)C1—C2—C6—C30.0 (4)
C7—C1—C2—C6179.9 (3)C4—C3—C6—C20.0 (4)
C6—C3—C4—C50.2 (4)C8—C3—C6—C2179.9 (3)
C8—C3—C4—C5180.0 (3)C5—C1—C7—O11.8 (5)
C2—C1—C5—C40.2 (4)C2—C1—C7—O1178.2 (3)
C7—C1—C5—C4179.7 (3)C4—C3—C8—O2179.2 (3)
C3—C4—C5—C10.2 (4)C6—C3—C8—O20.6 (5)

Experimental details

Crystal data
Chemical formulaC8H6O2
Mr134.13
Crystal system, space groupOrthorhombic, Pca21
Temperature (K)295
a, b, c (Å)12.8811 (5), 3.8933 (3), 13.3202 (9)
V3)668.01 (7)
Z4
Radiation typeMo Kα
µ (mm1)0.10
Crystal size (mm)0.20 × 0.10 × 0.10
Data collection
DiffractometerBruker SMART 4K CCD area-detector
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
3959, 653, 563
Rint0.030
(sin θ/λ)max1)0.606
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.042, 0.112, 1.04
No. of reflections653
No. of parameters91
No. of restraints1
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.16, 0.10

Computer programs: SMART (Bruker, 2001), SAINT (Bruker, 2001), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

 

Acknowledgements

This study was financially supported by a Key Project (No. Z2006zd02) of Huangshi Institute of Technology. The authors thank Dr Xiang-Gao Meng for the crystallographic data collection.

References

First citationBritton, D. (1998). J. Chem. Crystallogr. 28, 601–604.  Web of Science CSD CrossRef CAS
First citationBruker (2001). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals

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.

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
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