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

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890

2,4-Di­meth­oxy­benzaldehyde azine

aDepartment of Chemistry, Rajshahi University of Engineering and Technology, Rajshahi 6204, Bangladesh, bDepartment of Chemistry, Rajshahi University, Rajshahi 6205, Bangladesh, and cDipartimento di Scienze Chimiche, Via Licio Giorgieri 1, 34127 Trieste, Italy
*Correspondence e-mail: ttofazzal@yahoo.com

(Received 9 September 2009; accepted 21 September 2009; online 26 September 2009)

The title mol­ecule, C18H20N2O4, is located on a crystallographic centre of symmetry. The meth­oxy groups are coplanar with the benzene ring [interplanar angles of 14.4 (2) and 3.1 (3)°], indicating a conjugation effect.

Related literature

For the structures of related compounds, see: Narayana et al. (2007[Narayana, B., Yathirajan, H. S., Sarojini, B. K. & Bolte, M. (2007). Private communication (deposition number 653075). CCDC, Union Road, Cambridge, England.]); Liu et al. (2007[Liu, G., Xie, L., Wang, Y. & Wang, J.-D. (2007). Acta Cryst. E63, o2611.]); Takakashi et al. (2006[Takakashi, H., Kubo, K., Takechi, H., Matsumoto, T. & Ideta, K. (2006). J. Oleo Sci. 55, 483-486.]). For a statistical study of meth­oxy groups bound to phenyl rings, see: Hummel et al. (1988[Hummel, W., Huml, K. & Burgi, H.-B. (1988). Helv. Chim. Acta, 71, 1291-1302.]).

[Scheme 1]

Experimental

Crystal data
  • C18H20N2O4

  • Mr = 328.36

  • Monoclinic, P 21 /c

  • a = 6.775 (2) Å

  • b = 9.014 (3) Å

  • c = 14.081 (3) Å

  • β = 100.42 (2)°

  • V = 845.7 (4) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 0.09 mm−1

  • T = 293 K

  • 0.45 × 0.30 × 0.12 mm

Data collection
  • Enraf–Nonius DIP1030 image-plate diffractometer

  • Absorption correction: none

  • 3535 measured reflections

  • 1293 independent reflections

  • 719 reflections with I > 2σ(I)

  • Rint = 0.058

  • θmax = 24.1°

Refinement
  • R[F2 > 2σ(F2)] = 0.045

  • wR(F2) = 0.121

  • S = 0.84

  • 1293 reflections

  • 110 parameters

  • H-atom parameters constrained

  • Δρmax = 0.12 e Å−3

  • Δρmin = −0.10 e Å−3

Data collection: XPRESS (MacScience, 2002[MacScience (2002). XPRESS. MacScience Co. Ltd, Yokohama, Japan.]; cell refinement: DENZO (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 and SCALEPACK (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.]); 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: ORTEP-3 for Windows (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]); software used to prepare material for publication: WinGX (Farrugia, 1999[Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837-838.]).

Supporting information


Comment top

The molecule of the title compound (Fig. 1) possesses a crystallographically imposed inversion centre at the midpoint of the N—N bond. Thus the conformation about the N1—N1i azine bridge (symmetry code: (i) -x - 1, -y + 1, -z + 1) is trans, with a torsion angle C1—N1—N1'—C1' of 180°. The molecule has coplanar non hydrogen atoms as found in other similar structures (Narayana et al., 2007; Takakashi et al., 2006). The coplanarity of methoxy groups with the benzene ring suggests the presence of a conjugation effect (Hummel et al., 1988). The bond distance N1—N1i of 1.414 (4) Å, is comparable to those measured in the structure of methoxybenzaldehyde azine and N,N'-bis(4-hydroxybenzylidene)-hydrazine, which are 1.418 and 1.415 Å, respectively (Narayana et al., 2007; Liu et al., 2007). The crystal packing does not show any π-π stacking interactions between aromatic rings.

Related literature top

For the structures of related compounds, see: Narayana et al. (2007); Liu et al. (2007); Takakashi et al. (2006). For a statistical study of methoxy groups bound to phenyl rings, see: Hummel et al. (1988).

Experimental top

Hydrazine hydrate (99.99%) (0.13 g, 2.5 mmol) was added to a solution of 2,4-dimethoxybenzaldehyde (0.83 g, 5 mmol) in methanol (10 ml) with constant stirring for 5 min, at room temperature. A light yellow precipitate was formed, which was separated by filtration, washed with methanol and dried at 70°C for 1 h and then preserved in vacuo over anhydrous CaCl2 (0.43 g, 44.79%, m.p. 473 K). The compound was soluble in chloroform, benzene and toluene whereas insoluble in acetonitrile, methanol and ethanol. The compound (0.37 g) was dissolved in chloroform (60 ml) at boiling temperature and allowed to stand at room temperature (20–25°C). Bright large yellow crystals, suitable for X-ray single-crystal analysis, were obtained after 7 days. The crystals were collected, washed with absolute ethanol and dried in vacuo over anhydrous CaCl2.

Refinement top

All H atoms were located geometrically and treated as riding atoms, with C—H = 0.93–0.96 Å, and with Uiso(H) = 1.2Ueq(C) or 1.5Ueq(C) for methyl H atoms.

Computing details top

Data collection: XPRESS (MacScience, 2002; cell refinement: DENZO (Otwinowski & Minor, 1997); data reduction: DENZO and SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top
[Figure 1] Fig. 1. ORTEP drawing (ellipsoids at the 40% probability level) of the title compound with atom labelling scheme. Primed atom at -x - 1, -y + 1, -z + 1.
2,4-Dimethoxybenzaldehyde azine top
Crystal data top
C18H20N2O4F(000) = 348
Mr = 328.36Dx = 1.289 Mg m3
Monoclinic, P21/cMelting point: 475 K
Hall symbol: -P 2ybcMo Kα radiation, λ = 0.71073 Å
a = 6.775 (2) ÅCell parameters from 482 reflections
b = 9.014 (3) Åθ = 3.6–20.7°
c = 14.081 (3) ŵ = 0.09 mm1
β = 100.42 (2)°T = 293 K
V = 845.7 (4) Å3Plate, yellow
Z = 20.45 × 0.30 × 0.12 mm
Data collection top
Enraf–Nonius DIP1030 image-plate
diffractometer
719 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.058
Graphite monochromatorθmax = 24.1°, θmin = 2.9°
ϕ–scans with narrow framesh = 77
3535 measured reflectionsk = 1010
1293 independent reflectionsl = 1616
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.045H-atom parameters constrained
wR(F2) = 0.121 w = 1/[σ2(Fo2) + (0.0678P)2]
where P = (Fo2 + 2Fc2)/3
S = 0.84(Δ/σ)max < 0.001
1293 reflectionsΔρmax = 0.12 e Å3
110 parametersΔρmin = 0.10 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.070 (13)
Crystal data top
C18H20N2O4V = 845.7 (4) Å3
Mr = 328.36Z = 2
Monoclinic, P21/cMo Kα radiation
a = 6.775 (2) ŵ = 0.09 mm1
b = 9.014 (3) ÅT = 293 K
c = 14.081 (3) Å0.45 × 0.30 × 0.12 mm
β = 100.42 (2)°
Data collection top
Enraf–Nonius DIP1030 image-plate
diffractometer
719 reflections with I > 2σ(I)
3535 measured reflectionsRint = 0.058
1293 independent reflectionsθmax = 24.1°
Refinement top
R[F2 > 2σ(F2)] = 0.0450 restraints
wR(F2) = 0.121H-atom parameters constrained
S = 0.84Δρmax = 0.12 e Å3
1293 reflectionsΔρmin = 0.10 e Å3
110 parameters
Special details top

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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
N10.4202 (3)0.4904 (2)0.53948 (13)0.0857 (6)
O10.0297 (2)0.77203 (18)0.52320 (12)0.0960 (6)
O20.4398 (2)0.55904 (18)0.80720 (11)0.0952 (6)
C10.2709 (4)0.5738 (3)0.53259 (16)0.0833 (7)
H10.28000.63760.48000.100*
C20.0880 (3)0.5722 (2)0.60384 (15)0.0745 (6)
C30.0667 (3)0.6732 (2)0.59790 (16)0.0768 (6)
C40.2433 (3)0.6732 (2)0.66487 (16)0.0785 (7)
H40.34310.74250.66060.094*
C50.2699 (3)0.5695 (3)0.73791 (16)0.0787 (6)
C60.1196 (4)0.4673 (3)0.74624 (17)0.0850 (7)
H60.13720.39840.79620.102*
C70.0547 (3)0.4704 (3)0.67925 (18)0.0830 (7)
H70.15460.40170.68450.100*
C80.1918 (4)0.8551 (3)0.49880 (19)0.1041 (9)
H8A0.14290.91850.44490.156*
H8B0.29050.78850.48200.156*
H8C0.25140.91440.55310.156*
C90.5936 (3)0.6675 (3)0.80431 (19)0.1042 (9)
H9A0.70460.64880.85570.156*
H9B0.54100.76480.81180.156*
H9C0.63810.66140.74350.156*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0716 (13)0.0972 (13)0.0854 (14)0.0055 (12)0.0066 (9)0.0007 (11)
O10.0858 (11)0.1004 (12)0.0995 (12)0.0022 (9)0.0106 (9)0.0169 (10)
O20.0820 (11)0.1060 (13)0.0915 (12)0.0027 (9)0.0012 (9)0.0038 (9)
C10.0778 (16)0.0904 (16)0.0803 (15)0.0037 (13)0.0101 (13)0.0021 (12)
C20.0693 (14)0.0799 (14)0.0732 (14)0.0017 (12)0.0099 (12)0.0017 (12)
C30.0782 (15)0.0787 (15)0.0728 (14)0.0082 (13)0.0118 (13)0.0026 (12)
C40.0734 (15)0.0799 (15)0.0818 (15)0.0017 (12)0.0132 (13)0.0029 (13)
C50.0722 (15)0.0864 (15)0.0755 (15)0.0053 (13)0.0084 (13)0.0065 (13)
C60.0806 (16)0.0919 (16)0.0815 (16)0.0009 (13)0.0114 (14)0.0056 (13)
C70.0772 (16)0.0870 (16)0.0841 (16)0.0032 (12)0.0126 (13)0.0010 (13)
C80.1061 (19)0.0956 (17)0.113 (2)0.0067 (16)0.0255 (16)0.0164 (15)
C90.0775 (16)0.115 (2)0.114 (2)0.0073 (15)0.0006 (15)0.0033 (16)
Geometric parameters (Å, º) top
N1—C11.278 (3)C4—H40.9300
N1—N1i1.414 (4)C5—C61.393 (3)
O1—C31.366 (2)C6—C71.372 (3)
O1—C81.422 (3)C6—H60.9300
O2—C51.371 (3)C7—H70.9300
O2—C91.435 (3)C8—H8A0.9600
C1—C21.446 (3)C8—H8B0.9600
C1—H10.9300C8—H8C0.9600
C2—C71.391 (3)C9—H9A0.9600
C2—C31.402 (3)C9—H9B0.9600
C3—C41.383 (3)C9—H9C0.9600
C4—C51.378 (3)
C1—N1—N1i111.8 (2)C7—C6—C5118.7 (2)
C3—O1—C8119.13 (18)C7—C6—H6120.7
C5—O2—C9116.98 (19)C5—C6—H6120.7
N1—C1—C2122.2 (2)C6—C7—C2122.6 (2)
N1—C1—H1118.9C6—C7—H7118.7
C2—C1—H1118.9C2—C7—H7118.7
C7—C2—C3117.0 (2)O1—C8—H8A109.5
C7—C2—C1122.4 (2)O1—C8—H8B109.5
C3—C2—C1120.5 (2)H8A—C8—H8B109.5
O1—C3—C4122.7 (2)O1—C8—H8C109.5
O1—C3—C2115.7 (2)H8A—C8—H8C109.5
C4—C3—C2121.5 (2)H8B—C8—H8C109.5
C5—C4—C3119.3 (2)O2—C9—H9A109.5
C5—C4—H4120.4O2—C9—H9B109.5
C3—C4—H4120.4H9A—C9—H9B109.5
O2—C5—C4123.9 (2)O2—C9—H9C109.5
O2—C5—C6115.3 (2)H9A—C9—H9C109.5
C4—C5—C6120.8 (2)H9B—C9—H9C109.5
N1i—N1—C1—C2178.8 (2)C2—C3—C4—C51.5 (3)
N1—C1—C2—C76.4 (3)C9—O2—C5—C42.6 (3)
N1—C1—C2—C3175.1 (2)C9—O2—C5—C6176.66 (18)
C8—O1—C3—C415.1 (3)C3—C4—C5—O2179.32 (18)
C8—O1—C3—C2166.0 (2)C3—C4—C5—C61.5 (3)
C7—C2—C3—O1179.90 (18)O2—C5—C6—C7179.73 (19)
C1—C2—C3—O11.5 (3)C4—C5—C6—C71.0 (3)
C7—C2—C3—C41.0 (3)C5—C6—C7—C20.5 (3)
C1—C2—C3—C4179.62 (19)C3—C2—C7—C60.5 (3)
O1—C3—C4—C5179.68 (18)C1—C2—C7—C6179.1 (2)
Symmetry code: (i) x1, y+1, z+1.

Experimental details

Crystal data
Chemical formulaC18H20N2O4
Mr328.36
Crystal system, space groupMonoclinic, P21/c
Temperature (K)293
a, b, c (Å)6.775 (2), 9.014 (3), 14.081 (3)
β (°) 100.42 (2)
V3)845.7 (4)
Z2
Radiation typeMo Kα
µ (mm1)0.09
Crystal size (mm)0.45 × 0.30 × 0.12
Data collection
DiffractometerEnraf–Nonius DIP1030 image-plate
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
3535, 1293, 719
Rint0.058
θmax (°)24.1
(sin θ/λ)max1)0.575
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.045, 0.121, 0.84
No. of reflections1293
No. of parameters110
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.12, 0.10

Computer programs: XPRESS (MacScience, 2002, DENZO (Otwinowski & Minor, 1997), DENZO and SCALEPACK (Otwinowski & Minor, 1997), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997), WinGX (Farrugia, 1999).

 

Acknowledgements

MAAAAI is grateful to the Department of Chemistry, Rajshahi University of Engineering and Technology, for a research grant. MTHT thanks the Department of Chemistry, Rajshahi University, for the provision of laboratory facilities.

References

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 citationHummel, W., Huml, K. & Burgi, H.-B. (1988). Helv. Chim. Acta, 71, 1291–1302.  CrossRef CAS Web of Science Google Scholar
First citationLiu, G., Xie, L., Wang, Y. & Wang, J.-D. (2007). Acta Cryst. E63, o2611.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationMacScience (2002). XPRESS. MacScience Co. Ltd, Yokohama, Japan.  Google Scholar
First citationNarayana, B., Yathirajan, H. S., Sarojini, B. K. & Bolte, M. (2007). Private communication (deposition number 653075). CCDC, Union Road, Cambridge, England.  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 citationTakakashi, H., Kubo, K., Takechi, H., Matsumoto, T. & Ideta, K. (2006). J. Oleo Sci. 55, 483–486.  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.

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Follow Acta Cryst. E
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds