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Redetermination of 1,4-di­meth­oxy­benzene

aDepartment of Chemistry, Washington and Jefferson College, 60 South Lincoln Street, Washington, PA 15301, USA, and bDepartment of Chemistry, University of Utah, Salt Lake City, UT 84112, USA
*Correspondence e-mail: riuliucci@washjeff.edu

(Received 9 December 2008; accepted 30 December 2008; online 8 January 2009)

The structure of the centrosymmetric title compound, C8H10O2, originally determined by Goodwin et al. [Acta Cryst.(1950), 3, 279–284], has been redetermined to modern standards of precision to aid in its use as a model compound for 13C chemical-shift tensor measurements in single-crystal NMR studies. In the crystal structure, a C—H⋯O inter­action helps to establish the packing.

Related literature

For previous structural studies of the title compound, see: Goodwin et al. (1950[Goodwin, T. H., Przybylska, M. & Robertson, J. M. (1950). Acta Cryst. 3, 279-284.]); Carter et al. (1988[Carter, C. M., Facelli, J. C., Alderman, D. W., Grant, D. M., Dalley, N. K. & Wilson, B. E. (1988). J. Chem. Soc. Faraday Trans. 1, 84, 3673-3690.]).

[Scheme 1]

Experimental

Crystal data
  • C8H10O2

  • Mr = 138.16

  • Orthorhombic, P b c a

  • a = 7.1757 (3) Å

  • b = 6.2769 (2) Å

  • c = 16.5573 (7) Å

  • V = 745.76 (5) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.09 mm−1

  • T = 150 (1) K

  • 0.33 × 0.30 × 0.23 mm

Data collection
  • Nonius KappaCCD diffractometer

  • Absorption correction: multi-scan (DENZO–SMN; Otwinowski & Minor, 1997[Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307-326. New York: Academic Press.]) Tmin = 0.972, Tmax = 0.980

  • 1510 measured reflections

  • 847 independent reflections

  • 732 reflections with I > 2σ(I)

  • Rint = 0.013

Refinement
  • R[F2 > 2σ(F2)] = 0.037

  • wR(F2) = 0.101

  • S = 1.09

  • 847 reflections

  • 66 parameters

  • All H-atom parameters refined

  • Δρmax = 0.19 e Å−3

  • Δρmin = −0.16 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C4—H4A⋯O1i 1.019 (16) 2.552 (15) 3.4381 (15) 145.1 (10)
Symmetry code: (i) [-x, y+{\script{1\over 2}}, -z+{\script{1\over 2}}].

Data collection: COLLECT (Hooft, 1998[Hooft, R. W. W. (1998). COLLECT. Nonius BV, Delft, The Netherlands.]); cell refinement: DENZO–SMN (Otwinowski & Minor, 1997[Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307-326. New York: Academic Press.]); data reduction: DENZO–SMN; program(s) used to solve structure: SIR97 (Altomare et al., 1999[Altomare, A., Burla, M. C., Camalli, M., Cascarano, G. L., Giacovazzo, C., Guagliardi, A., Moliterni, A. G. G., Polidori, G. & Spagna, R. (1999). J. Appl. Cryst. 32, 115-119.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: WinGX (Farrugia, 1999[Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837-838.]) and ORTEP-3 (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]); software used to prepare material for publication: publCIF (Westrip, 2009[Westrip, S. P. (2009). publCIF. In preparation.]).

Supporting information


Comment top

Large single-crystals of organic compounds can be challenging to grow. Substituted methoxybenzenes are one exception and single-crystals on the order of centimeters can be obtained. The ease of crystal growth has enabled substituted methoxybenzenes to be studied by single-crystal NMR experiments. Pioneering work on the development of the two-dimensional single-crystal chemical-shift chemical-shift correlation NMR experiments utilized large crystals of 1,4-dimethoxybenzene (Carter et al., 1988). In 1950 Goodwin et al. obtained the first X-ray diffraction structure for 1,4-dimethoxybenzene. This structure (R-factor = 0.12) is shown in Fig. 1 and reported an unusual H–C–C angle of 75.7°, which prompted the acquisition of a second structure (Carter et al., 1988). More typical H–C–C angles were observed with this new refinement and this structure (R-factor = 0.067) was used to assign tensor orientations in the single-crystal NMR analysis. Inadvertently, the second structure was never submitted to the Cambridge Crystallographic database. Here, the acquisition of a third structure is reported to correct this oversight. The new structure (R-factor = 0.038) is shown in Fig. 2. The unit-cell and space group of the previous studies are confirmed.

Acquisition of this third, more accurate, structure is beneficial to NMR studies because the 13C chemical shift tensor data of 1,4-dimethoxybenzene continue to serve as a standard to evaluate new chemical-shift tensor measurement methods as well as to assess electronic structure methods for computing magnetic properties of molecules.

Related literature top

For previous structural studies of the title compound, see: Goodwin et al. (1950); Carter et al. (1988).

Refinement top

The H atoms were located in difference maps and their positions and Uiso values were freely refined.

Computing details top

Data collection: COLLECT (Hooft, 1998); cell refinement: DENZO–SMN (Otwinowski & Minor, 1997); data reduction: DENZO–SMN (Otwinowski & Minor, 1997); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: WinGX (Farrugia, 1999) and ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: publCIF (Westrip, 2009).

Figures top
[Figure 1] Fig. 1. The structure of (I) according to Goodwin et al. (1950).
[Figure 2] Fig. 2. The redetermined structure of (I) from the present study.
1,4-dimethoxybenzene top
Crystal data top
C8H10O2Dx = 1.231 Mg m3
Mr = 138.16Melting point: 329 K
Orthorhombic, PbcaMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2abCell parameters from 13221 reflections
a = 7.1757 (3) Åθ = 1.0–27.5°
b = 6.2769 (2) ŵ = 0.09 mm1
c = 16.5573 (7) ÅT = 150 K
V = 745.76 (5) Å3Prism, colorless
Z = 40.33 × 0.30 × 0.23 mm
F(000) = 296
Data collection top
Nonius KappaCCD
diffractometer
847 independent reflections
Radiation source: fine-focus sealed tube732 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.013
ϕ and ω scansθmax = 27.5°, θmin = 3.8°
Absorption correction: multi-scan
(DENZO–SMN; Otwinowski & Minor, 1997)
h = 99
Tmin = 0.972, Tmax = 0.980k = 88
1510 measured reflectionsl = 2121
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)] = 0.037Hydrogen site location: difference Fourier map
wR(F2) = 0.101All H-atom parameters refined
S = 1.09 w = 1/[σ2(Fo2) + (0.0517P)2 + 0.1487P]
where P = (Fo2 + 2Fc2)/3
847 reflections(Δ/σ)max < 0.001
66 parametersΔρmax = 0.19 e Å3
0 restraintsΔρmin = 0.16 e Å3
none constraints
Crystal data top
C8H10O2V = 745.76 (5) Å3
Mr = 138.16Z = 4
Orthorhombic, PbcaMo Kα radiation
a = 7.1757 (3) ŵ = 0.09 mm1
b = 6.2769 (2) ÅT = 150 K
c = 16.5573 (7) Å0.33 × 0.30 × 0.23 mm
Data collection top
Nonius KappaCCD
diffractometer
847 independent reflections
Absorption correction: multi-scan
(DENZO–SMN; Otwinowski & Minor, 1997)
732 reflections with I > 2σ(I)
Tmin = 0.972, Tmax = 0.980Rint = 0.013
1510 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0370 restraints
wR(F2) = 0.101All H-atom parameters refined
S = 1.09Δρmax = 0.19 e Å3
847 reflectionsΔρmin = 0.16 e Å3
66 parameters
Special details top

Experimental. The program DENZO-SMN (Otwinowski & Minor, 1997) uses a scaling algorithm (Fox & Holmes, 1966) which effectively corrects for absorption effects. High redundancy data were used in the scaling program hence the 'multi-scan' code word was used. No transmission coefficients are available from the program (only scale factors for each frame). The scale factors in the experimental table are calculated from the 'size' command in the SHELXL97 input file.

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 > 2σ(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
O10.01305 (11)0.15781 (13)0.15601 (4)0.0315 (3)
C20.09537 (13)0.10269 (16)0.06126 (6)0.0257 (3)
C30.09472 (14)0.18955 (17)0.01604 (6)0.0264 (3)
C10.00160 (12)0.08587 (17)0.07767 (6)0.0243 (3)
C40.0849 (2)0.3490 (2)0.17534 (8)0.0410 (3)
H20.1619 (17)0.175 (2)0.1048 (8)0.033 (3)*
H30.1604 (18)0.319 (2)0.0253 (7)0.031 (3)*
H4A0.061 (2)0.375 (2)0.2352 (10)0.050 (4)*
H4B0.221 (3)0.323 (2)0.1672 (9)0.057 (5)*
H4C0.036 (2)0.470 (3)0.1413 (11)0.056 (4)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0387 (5)0.0328 (5)0.0231 (4)0.0040 (3)0.0018 (3)0.0031 (3)
C20.0249 (5)0.0268 (5)0.0255 (5)0.0015 (4)0.0017 (4)0.0043 (4)
C30.0259 (5)0.0244 (5)0.0288 (6)0.0029 (4)0.0012 (4)0.0014 (4)
C10.0241 (5)0.0267 (5)0.0220 (5)0.0028 (4)0.0012 (3)0.0007 (4)
C40.0534 (8)0.0377 (7)0.0321 (6)0.0092 (6)0.0004 (5)0.0104 (5)
Geometric parameters (Å, º) top
O1—C11.3759 (12)C3—C11.3937 (14)
O1—C41.4269 (14)C3—H30.953 (13)
C2—C11.3883 (15)C4—H4A1.020 (16)
C2—C3i1.3912 (15)C4—H4B0.998 (18)
C2—H20.977 (13)C4—H4C1.010 (18)
C3—C2i1.3912 (15)
C1—O1—C4117.26 (9)O1—C1—C3124.51 (10)
C1—C2—C3i120.83 (9)C2—C1—C3119.68 (10)
C1—C2—H2119.4 (7)O1—C4—H4A105.8 (8)
C3i—C2—H2119.8 (7)O1—C4—H4B108.4 (9)
C2i—C3—C1119.48 (10)H4A—C4—H4B108.8 (12)
C2i—C3—H3118.7 (8)O1—C4—H4C109.7 (9)
C1—C3—H3121.8 (8)H4A—C4—H4C111.2 (12)
O1—C1—C2115.81 (9)H4B—C4—H4C112.6 (12)
C4—O1—C1—C2178.76 (10)C3i—C2—C1—C30.10 (16)
C4—O1—C1—C31.69 (15)C2i—C3—C1—O1179.44 (9)
C3i—C2—C1—O1179.47 (9)C2i—C3—C1—C20.10 (16)
Symmetry code: (i) x, y, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C4—H4A···O1ii1.019 (16)2.552 (15)3.4381 (15)145.1 (10)
Symmetry code: (ii) x, y+1/2, z+1/2.

Experimental details

Crystal data
Chemical formulaC8H10O2
Mr138.16
Crystal system, space groupOrthorhombic, Pbca
Temperature (K)150
a, b, c (Å)7.1757 (3), 6.2769 (2), 16.5573 (7)
V3)745.76 (5)
Z4
Radiation typeMo Kα
µ (mm1)0.09
Crystal size (mm)0.33 × 0.30 × 0.23
Data collection
DiffractometerNonius KappaCCD
diffractometer
Absorption correctionMulti-scan
(DENZO–SMN; Otwinowski & Minor, 1997)
Tmin, Tmax0.972, 0.980
No. of measured, independent and
observed [I > 2σ(I)] reflections
1510, 847, 732
Rint0.013
(sin θ/λ)max1)0.649
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.037, 0.101, 1.09
No. of reflections847
No. of parameters66
H-atom treatmentAll H-atom parameters refined
Δρmax, Δρmin (e Å3)0.19, 0.16

Computer programs: COLLECT (Hooft, 1998), DENZO–SMN (Otwinowski & Minor, 1997), SIR97 (Altomare et al., 1999), SHELXL97 (Sheldrick, 2008), WinGX (Farrugia, 1999) and ORTEP-3 (Farrugia, 1997), publCIF (Westrip, 2009).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C4—H4A···O1i1.019 (16)2.552 (15)3.4381 (15)145.1 (10)
Symmetry code: (i) x, y+1/2, z+1/2.
 

Acknowledgements

This work was supported by NSF grant ECC0304433 and NIH grant 5R01GM08521-44. Financial support for CLH was provided by Presidential Discretionary Funds from Washington and Jefferson College.

References

First citationAltomare, A., Burla, M. C., Camalli, M., Cascarano, G. L., Giacovazzo, C., Guagliardi, A., Moliterni, A. G. G., Polidori, G. & Spagna, R. (1999). J. Appl. Cryst. 32, 115–119.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationCarter, C. M., Facelli, J. C., Alderman, D. W., Grant, D. M., Dalley, N. K. & Wilson, B. E. (1988). J. Chem. Soc. Faraday Trans. 1, 84, 3673–3690.  Google Scholar
First citationFarrugia, L. J. (1997). J. Appl. Cryst. 30, 565.  CrossRef IUCr Journals Google Scholar
First citationFarrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838.  CrossRef CAS IUCr Journals Google Scholar
First citationGoodwin, T. H., Przybylska, M. & Robertson, J. M. (1950). Acta Cryst. 3, 279–284.  CSD CrossRef CAS IUCr Journals Web of Science Google Scholar
First citationHooft, R. W. W. (1998). COLLECT. Nonius BV, Delft, The Netherlands.  Google Scholar
First citationOtwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307–326. New York: Academic Press.  Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationWestrip, S. P. (2009). publCIF. In preparation.  Google Scholar

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