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Acta Crystallogr Sect E Struct Rep Online. 2009 February 1; 65(Pt 2): o436.
Published online 2009 January 31. doi:  10.1107/S1600536809003432
PMCID: PMC2968382

4-Bromo-N-(3,4,5-trimethoxy­benzyl­idene)aniline

Abstract

The title compound, C16H16BrNO3, adopts an E configuration with respect to the imine C=N bond. The two benzene rings are twisted with respect to each other at an angle of 38.3 (1)°. In the crystal structure, mol­ecules are connected by weak bifurcated C—H(...)(O, O) hydrogen bonds, forming a helical chain along the b axis.

Related literature

The structure of the isotypic 4-chloro compound was reported by Khalaji et al. (2009 [triangle]). For structures containing a 4-bromo­aniline unit, see: Khalaji et al. (2007 [triangle]); Khalaji & Harrison (2008 [triangle]).

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Object name is e-65-0o436-scheme1.jpg

Experimental

Crystal data

  • C16H16BrNO3
  • M r = 350.21
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-65-0o436-efi1.jpg
  • a = 7.1951 (4) Å
  • b = 8.3722 (5) Å
  • c = 13.2882 (8) Å
  • β = 104.413 (3)°
  • V = 775.27 (8) Å3
  • Z = 2
  • Mo Kα radiation
  • μ = 2.66 mm−1
  • T = 296 (2) K
  • 0.40 × 0.30 × 0.15 mm

Data collection

  • Bruker APEXII CCD diffractometer
  • Absorption correction: multi-scan (SADABS; Bruker, 2006 [triangle]) T min = 0.403, T max = 0.671
  • 18229 measured reflections
  • 3497 independent reflections
  • 3064 reflections with I > 2σ(I)
  • R int = 0.023

Refinement

  • R[F 2 > 2σ(F 2)] = 0.025
  • wR(F 2) = 0.065
  • S = 1.09
  • 3497 reflections
  • 193 parameters
  • 1 restraint
  • H-atom parameters constrained
  • Δρmax = 0.30 e Å−3
  • Δρmin = −0.53 e Å−3
  • Absolute structure: Flack (1983 [triangle]), 1511 Friedel pairs
  • Flack parameter: 0.012 (6)

Data collection: APEX2 (Bruker, 2008 [triangle]); cell refinement: SAINT (Bruker, 2008 [triangle]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: ORTEP-3 (Farrugia, 1997 [triangle]); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2003 [triangle]).

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809003432/wn2308sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809003432/wn2308Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

supplementary crystallographic information

Comment

Recently, we reported two Schiff-base compounds with 4-bromoaniline units that have been structurally characterized (Khalaji et al., 2007; Khalaji & Harrison, 2008). In continuation of these studies, the title compound was prepared and its structure has been determined.

An ORTEP plot, with the atomic numbering scheme is depicted in Fig. 1. The two benzene rings are twisted with respect to each other at an angle of 38.3 (1)°. In the crystal structure, the molecules are connected by weak bifurcated C—H···(O, O) hydrogen bonds, forming a helical chain along the b axis.

The C7═N1 bond length of 1.268 (3) Å conforms to the value for a double bond, and is slightly shorter than the corresponding bond length in N-(2-benzylidenepropylidene)-4-bromoaniline [C23═N23 1.288 (6) Å; Khalaji et al., 2007] and β-phenylcinnamaldehyde-4-bromoaniline [C7═N1 1.277 (4) Å; Khalaji & Harrison, 2008]. The C4—N1 bond length of 1.421 (2) Å conforms to the value for a single bond, and, in turn, is slightly longer than the corresponding bond length in N-(2-benzylidenepropylidene)-4-bromoaniline [C24—N23 1.411 (7) Å] and β-phenylcinnamaldehyde-4-bromoaniline [C6—N1 1.407 (4) Å]. All other bond lengths in the three related Schiff-base compounds are quite similar. For the title compound, the torsion angle, C8—C7—N1—C4, is 179.20 (18)°, indicating a virtually planar E-configuration with respect to the imine C═N bond (Khalaji et al., 2007; Khalaji & Harrison, 2008).

In comparison with the isotypic structure of C16H16ClNO3 (Dehno Khalaji et al., 2009), all interatomic distances and angles (except those involving the halogen atom) are very similar.

Experimental

The title compound was prepared by the reaction of 3,4,5-trimethoxybenzaldehyde (1 mmol, 0.196 g) and 4-bromoaniline (1 mmol, 0.172 g), which were dissolved in methanol (10 ml). The mixture was stirred at room temperature for 30 min. Colourless single crystals suitable for X-ray structure analysis were obtained by recrystallization from a methanol/chloroform (1:1 v/v) solution.

Refinement

H atoms were positioned geometrically (C—H = 0.93 or 0.96 Å) and refined as riding, with Uiso(H) = 1.2Ueq(C) or 1.5Ueq(methyl C), allowing for free rotation of the methyl groups.

Figures

Fig. 1.
The molecular structure of the title compound, with the atom-labelling. Displacement ellipsoids of non-H atoms are drawn at the 50% probability level. Hydrogen atoms are denoted by spheres of arbitrary radius.
Fig. 2.
A partial packing diagram, viewed along the a axis. H atoms not involved in the C—H···O hydrogen bonds have been omitted.

Crystal data

C16H16BrNO3F(000) = 356
Mr = 350.21Dx = 1.500 Mg m3
Monoclinic, P21Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ybCell parameters from 9957 reflections
a = 7.1951 (4) Åθ = 2.9–29.0°
b = 8.3722 (5) ŵ = 2.66 mm1
c = 13.2882 (8) ÅT = 296 K
β = 104.413 (3)°Block, colourless
V = 775.27 (8) Å30.40 × 0.30 × 0.15 mm
Z = 2

Data collection

Bruker APEXII CCD diffractometer3497 independent reflections
Radiation source: fine-focus sealed tube3064 reflections with I > 2σ(I)
graphiteRint = 0.023
ω scansθmax = 28.0°, θmin = 2.9°
Absorption correction: multi-scan (SADABS; Bruker, 2006)h = −9→9
Tmin = 0.403, Tmax = 0.671k = −10→10
18229 measured reflectionsl = −17→17

Refinement

Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.025H-atom parameters constrained
wR(F2) = 0.065w = 1/[σ2(Fo2) + (0.0339P)2 + 0.0173P] where P = (Fo2 + 2Fc2)/3
S = 1.09(Δ/σ)max = 0.002
3497 reflectionsΔρmax = 0.30 e Å3
193 parametersΔρmin = −0.53 e Å3
1 restraintAbsolute structure: Flack (1983), 1511 Friedel pairs
Primary atom site location: structure-invariant direct methodsFlack parameter: 0.012 (6)

Special details

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)

xyzUiso*/Ueq
Br10.99402 (3)0.96811 (5)0.988948 (16)0.06694 (9)
O1−0.26888 (18)0.4772 (2)0.36904 (9)0.0522 (3)
O2−0.46171 (19)0.29368 (19)0.46988 (11)0.0498 (3)
O3−0.3668 (2)0.2687 (2)0.67538 (12)0.0600 (4)
N10.2656 (2)0.6014 (2)0.79047 (14)0.0502 (4)
C10.7715 (3)0.8470 (2)0.92769 (15)0.0450 (4)
C20.6245 (3)0.8386 (3)0.97682 (18)0.0595 (6)
H20.63550.88911.04040.071*
C30.4614 (4)0.7546 (3)0.9308 (2)0.0604 (6)
H30.36340.74580.96480.072*
C40.4402 (3)0.6827 (2)0.83465 (15)0.0436 (4)
C50.5939 (3)0.6886 (3)0.78856 (16)0.0478 (5)
H50.58500.63680.72560.057*
C60.7594 (3)0.7705 (3)0.83532 (17)0.0498 (5)
H60.86180.77360.80430.060*
C70.2013 (3)0.6071 (2)0.69260 (16)0.0427 (4)
H70.27000.66510.65420.051*
C80.0246 (3)0.5272 (2)0.63686 (16)0.0411 (4)
C9−0.0833 (3)0.4364 (2)0.69019 (15)0.0432 (5)
H9−0.04540.42660.76210.052*
C10−0.2484 (3)0.3611 (2)0.63335 (16)0.0430 (4)
C11−0.3059 (3)0.3758 (2)0.52599 (16)0.0411 (4)
C12−0.1991 (2)0.4695 (3)0.47377 (12)0.0403 (3)
C13−0.0336 (3)0.5450 (2)0.53043 (16)0.0417 (4)
H130.03810.60780.49630.050*
C14−0.1666 (4)0.5679 (4)0.3108 (2)0.0785 (8)
H14A−0.16410.67790.33160.118*
H14B−0.22870.55910.23820.118*
H14C−0.03770.52840.32320.118*
C15−0.6378 (3)0.3769 (4)0.4588 (2)0.0673 (7)
H15A−0.65880.39720.52620.101*
H15B−0.74120.31330.41890.101*
H15C−0.63240.47650.42380.101*
C16−0.3111 (5)0.2366 (4)0.7828 (2)0.0761 (8)
H16A−0.18130.19830.80100.114*
H16B−0.39440.15690.79970.114*
H16C−0.31980.33270.82080.114*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
Br10.05738 (13)0.06441 (15)0.06520 (14)−0.01188 (12)−0.01083 (9)−0.00513 (15)
O10.0556 (7)0.0567 (8)0.0431 (6)−0.0113 (9)0.0100 (5)−0.0013 (9)
O20.0463 (7)0.0467 (8)0.0547 (8)−0.0096 (7)0.0092 (6)−0.0106 (7)
O30.0588 (9)0.0704 (10)0.0506 (9)−0.0236 (7)0.0135 (7)0.0033 (7)
N10.0478 (9)0.0533 (10)0.0498 (11)−0.0107 (8)0.0126 (8)−0.0056 (8)
C10.0423 (9)0.0395 (11)0.0456 (11)−0.0019 (8)−0.0036 (8)−0.0007 (8)
C20.0630 (13)0.0664 (15)0.0468 (12)−0.0018 (11)0.0094 (10)−0.0168 (10)
C30.0582 (13)0.0769 (18)0.0500 (14)−0.0086 (11)0.0208 (11)−0.0114 (10)
C40.0425 (9)0.0441 (12)0.0418 (10)−0.0030 (9)0.0060 (8)−0.0009 (8)
C50.0463 (10)0.0538 (14)0.0400 (11)−0.0014 (10)0.0044 (8)−0.0099 (9)
C60.0408 (10)0.0595 (14)0.0466 (12)−0.0002 (9)0.0060 (9)−0.0020 (10)
C70.0376 (9)0.0393 (10)0.0504 (12)−0.0019 (8)0.0095 (8)−0.0013 (8)
C80.0355 (9)0.0337 (9)0.0524 (11)0.0014 (7)0.0076 (8)−0.0044 (7)
C90.0418 (9)0.0433 (13)0.0442 (9)−0.0024 (7)0.0101 (7)−0.0026 (7)
C100.0434 (10)0.0377 (11)0.0497 (11)−0.0038 (8)0.0148 (8)−0.0041 (8)
C110.0378 (9)0.0345 (10)0.0503 (11)−0.0006 (8)0.0097 (8)−0.0080 (8)
C120.0412 (8)0.0356 (8)0.0449 (8)0.0025 (11)0.0122 (6)−0.0028 (11)
C130.0397 (9)0.0371 (10)0.0502 (11)−0.0020 (7)0.0148 (8)−0.0011 (8)
C140.0817 (17)0.102 (2)0.0505 (14)−0.0239 (16)0.0142 (13)0.0169 (14)
C150.0429 (11)0.0708 (17)0.0828 (18)−0.0044 (12)0.0056 (11)−0.0027 (13)
C160.0790 (17)0.086 (2)0.0611 (18)−0.0228 (16)0.0134 (15)0.0180 (13)

Geometric parameters (Å, °)

Br1—C11.8992 (19)C7—C81.464 (3)
O1—C121.358 (2)C7—H70.9300
O1—C141.414 (3)C8—C91.399 (3)
O2—C111.367 (2)C8—C131.379 (3)
O2—C151.421 (3)C9—H90.9300
O3—C161.409 (3)C10—C91.390 (3)
O3—C101.368 (2)C11—C101.388 (3)
C1—C21.376 (3)C12—C131.392 (3)
C1—C61.368 (3)C12—C111.397 (3)
C2—H20.9300C13—H130.9300
C3—C21.375 (3)C14—H14A0.9600
C3—H30.9300C14—H14B0.9600
C4—N11.421 (2)C14—H14C0.9600
C4—C31.386 (3)C15—H15A0.9600
C4—C51.392 (3)C15—H15B0.9600
C5—C61.380 (3)C15—H15C0.9600
C5—H50.9300C16—H16A0.9600
C6—H60.9300C16—H16B0.9600
C7—N11.268 (3)C16—H16C0.9600
O1—C12—C11115.25 (16)C6—C1—Br1119.56 (16)
O1—C12—C13125.52 (17)C6—C1—C2121.14 (18)
O1—C14—H14A109.5C6—C5—C4120.69 (19)
O1—C14—H14B109.5C6—C5—H5119.7
O1—C14—H14C109.5C7—N1—C4117.70 (17)
O2—C11—C10120.65 (17)C8—C7—H7118.3
O2—C11—C12119.28 (17)C8—C9—H9120.7
O2—C15—H15A109.5C8—C13—C12120.43 (18)
O2—C15—H15B109.5C8—C13—H13119.8
O2—C15—H15C109.5C9—C8—C7120.90 (18)
O3—C10—C9124.70 (18)C10—O3—C16118.18 (19)
O3—C10—C11114.39 (17)C10—C9—C8118.58 (18)
O3—C16—H16A109.5C10—C9—H9120.7
O3—C16—H16B109.5C10—C11—C12120.00 (17)
O3—C16—H16C109.5C11—O2—C15113.49 (18)
N1—C7—C8123.41 (18)C11—C10—C9120.91 (17)
N1—C7—H7118.3C12—O1—C14118.41 (17)
C1—C2—H2120.4C13—C8—C9120.83 (17)
C1—C6—C5119.45 (19)C13—C8—C7118.27 (17)
C1—C6—H6120.3C13—C12—C11119.23 (16)
C2—C1—Br1119.30 (15)C12—C13—H13119.8
C2—C3—C4121.2 (2)H14A—C14—H14B109.5
C2—C3—H3119.4H14A—C14—H14C109.5
C3—C2—C1119.1 (2)H14B—C14—H14C109.5
C3—C2—H2120.4H15A—C15—H15B109.5
C3—C4—N1118.17 (18)H15A—C15—H15C109.5
C3—C4—C5118.22 (19)H15B—C15—H15C109.5
C4—C3—H3119.4H16A—C16—H16B109.5
C4—C5—H5119.7H16A—C16—H16C109.5
C5—C4—N1123.56 (17)H16B—C16—H16C109.5
C5—C6—H6120.3
Br1—C1—C2—C3178.2 (2)C6—C1—C2—C3−1.4 (4)
Br1—C1—C6—C5−177.04 (17)C7—C8—C9—C10−179.05 (17)
O1—C12—C11—O23.6 (3)C7—C8—C13—C12179.05 (18)
O1—C12—C11—C10−179.35 (19)C8—C7—N1—C4179.19 (18)
O1—C12—C13—C8−179.36 (19)C9—C10—O3—C16−5.2 (3)
O2—C11—C10—O3−4.2 (3)C9—C8—C13—C12−1.5 (3)
O2—C11—C10—C9175.96 (17)C11—C10—O3—C16174.9 (2)
O3—C10—C9—C8179.93 (18)C11—C12—C13—C80.2 (3)
N1—C4—C3—C2−178.3 (2)C11—C10—C9—C8−0.2 (3)
N1—C4—C5—C6179.6 (2)C12—C11—C10—O3178.83 (19)
N1—C7—C8—C13178.51 (19)C12—C11—C10—C9−1.0 (3)
N1—C7—C8—C9−0.9 (3)C13—C8—C9—C101.5 (3)
C2—C1—C6—C52.6 (3)C13—C12—C11—O2−175.99 (19)
C3—C4—N1—C7144.8 (2)C13—C12—C11—C101.0 (3)
C3—C4—C5—C6−3.0 (3)C14—O1—C12—C11−179.1 (2)
C4—C3—C2—C1−2.0 (4)C14—O1—C12—C130.5 (3)
C4—C5—C6—C1−0.3 (4)C15—O2—C11—C1088.3 (2)
C5—C4—C3—C24.2 (4)C15—O2—C11—C12−94.7 (2)
C5—C4—N1—C7−37.8 (3)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
C7—H7···O1i0.932.633.272 (2)127
C7—H7···O2i0.932.633.553 (3)172

Symmetry codes: (i) −x, y+1/2, −z+1.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: WN2308).

References

  • Bruker (2006). SADABS Bruker AXS Inc., Madison, Wisconsin, USA.
  • Bruker (2008). APEX2 and SAINT Bruker AXS Inc., Madison, Wisconsin, USA.
  • Farrugia, L. J. (1997). J. Appl. Cryst.30, 565.
  • Flack, H. D. (1983). Acta Cryst. A39, 876–881.
  • Khalaji, A. D., Asghari, J., Fejfarová, K. & Dušek, M. (2009). Acta Cryst. E65, o253. [PMC free article] [PubMed]
  • Khalaji, A. D. & Harrison, W. T. A. (2008). Anal. Sci.24, x3–x4.
  • Khalaji, A. D., Slawin, A. M. Z. & Woollins, J. D. (2007). Acta Cryst. E63, o4257.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Spek, A. L. (2003). J. Appl. Cryst.36, 7–13.

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