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Acta Cryst. (2009). E65, o553    [ doi:10.1107/S1600536809004905 ]

(E)-4-Bromo-N-(2,4-dimethoxybenzylidene)aniline

A. D. Khalaji and J. Simpson

Abstract top

The title Schiff base compound, C15H14BrNO2, adopts an E configuration with respect to the C=N bond. The C and O atoms of the two methoxy substituents lie very close to the dimethoxyphenyl ring plane [maximum deviation = 0.17 (1) Å]. The dihedral angle between the two aromatic rings is 43.69 (16)°, while the plane through the central C-C=N-C system is inclined at 10.6 (6)° to the dimethoxyphenyl ring and 34.6 (3)° to the bromophenyl ring. In the crystal structure, each molecule is involved in the formation of two inversion-related dimers through weak C-H...N and C-H...O interactions, respectively. These contacts link the molecules into independent rows parallel to the b axis.

Comment top

As a continuation of our work on the synthesis and structural characterization of Schiff-base compounds (Khalaji et al., 2007; Khalaji & Harrison, 2008; Khalaji & Simpson, 2009), we report here the structure of the title compound, C15H14BrNO2, (I), Fig 1.

The compound adopts an E configuration with respect to the C1=N1 bond. The C4, O1 and C7 O2 methoxy substituents lie close to the plane of the C2···C9 ring (maximum deviation 0.17 (1) Å for C7. Bond lengths in the molecule are normal (Allen, et al., 1987) and similar to those found in related compounds (Khalaji et al., 2007; Khalaji & Harrison, 2008; Khalaji & Simpson 2009). The dihedral angle between the two aromatic rings is 43.69 (16) ° while the plane through the central C2—C2?N1—C10 system is inclined at 10.6 (6)° to the dimethoxyphenyl ring and 34.6 (3)° to the bromobenzene ring.

In the crystal structure, each molecule is involved in the formation of two inversion related dimers with R22(18) and R22(14) ring motifs (Bernstein et al. 1995) through weak C7—H7A···N1 and C4—H4···O2 interactions respectively, Table 1. These contacts link the molecules into independent rows parallel to the b axis, Fig. 2.

Related literature top

For related structures, see: Khalaji et al. (2007); Khalaji & Harrison (2008); Khalaji & Simpson (2009). For reference structural data, see: Allen et al. (1987). For graph-set motifs, see: Bernstein et al. (1995).

Experimental top

To a solution of 2,4-Dimethoxy benzaldehyde (332 mg, 0.2 mmol) in methanol (5 ml), cooled in an ice bath, a solution of 4-bromoaniline (344 mg, 0.2 mmol) in methanol (5 ml) was added slowly dropwise with constant stirring (1 h) at 298 k in the presence of molecular sieves. The mixture was filtered and the solution cooled to 273 K to give the compound in about 85% yield. Pale yellow crystals were grown from methanol.

Refinement top

H-atoms were refined using a riding model with d(C—H) = 0.95 Å, Uiso= 1.2Ueq (C) for aromatic and 0.98 Å, Uiso = 1.5Ueq (C) for CH3 H atoms.

Computing details top

Data collection: APEX2 (Bruker, 2006); cell refinement: APEX2 (Bruker, 2006) and SAINT (Bruker, 2006); data reduction: SAINT (Bruker, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008) and TITAN (Hunter & Simpson, 1999); molecular graphics: SHELXTL (Sheldrick, 2008) and Mercury (Macrae et al., 2006); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008), enCIFer (Allen et al., 2004), PLATON (Spek, 2009) and publCIF (Westrip, 2009).

Figures top
[Figure 1] Fig. 1. The structure of (I) with displacement ellipsoids for the non-hydrogen atoms drawn at the 50% probability level.
[Figure 2] Fig. 2. Crystal packing of (I) viewed down the a axis with hydrogen bonds drawn as dashed lines. H atoms not involved in hydrogen bonding have been omitted.
(E)-4-Bromo-N-(2,4-dimethoxybenzylidene)aniline top
Crystal data top
C15H14BrNO2F(000) = 648
Mr = 320.18Dx = 1.602 Mg m−3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 2351 reflections
a = 4.1323 (6) Åθ = 2.7–23.6°
b = 10.7406 (14) ŵ = 3.09 mm−1
c = 29.911 (4) ÅT = 89 K
β = 90.992 (8)°Rectangular plate, pale yellow
V = 1327.4 (3) Å30.25 × 0.10 × 0.02 mm
Z = 4
Data collection top
Bruker APEXII CCD area-detector
diffractometer		2390 independent reflections
Radiation source: fine-focus sealed tube1664 reflections with I > 2σ(I)
graphiteRint = 0.106
ω scansθmax = 25.3°, θmin = 2.0°
Absorption correction: multi-scan
(SADABS; Bruker, 2006)		h = −3→4
Tmin = 0.570, Tmax = 0.940k = −12→12
13728 measured reflectionsl = −35→35
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)] = 0.056Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.118H-atom parameters constrained
S = 1.21 w = 1/[σ2(Fo2) + (0.0212P)2 + 3P]
where P = (Fo2 + 2Fc2)/3
2390 reflections(Δ/σ)max < 0.001
174 parametersΔρmax = 0.83 e Å−3
0 restraintsΔρmin = −0.82 e Å−3
Crystal data top
C15H14BrNO2V = 1327.4 (3) Å3
Mr = 320.18Z = 4
Monoclinic, P21/cMo Kα radiation
a = 4.1323 (6) ŵ = 3.09 mm−1
b = 10.7406 (14) ÅT = 89 K
c = 29.911 (4) Å0.25 × 0.10 × 0.02 mm
β = 90.992 (8)°
Data collection top
Bruker APEXII CCD area-detector
diffractometer		2390 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2006)		1664 reflections with I > 2σ(I)
Tmin = 0.570, Tmax = 0.940Rint = 0.106
13728 measured reflectionsθmax = 25.3°
Refinement top
R[F2 > 2σ(F2)] = 0.056H-atom parameters constrained
wR(F2) = 0.118Δρmax = 0.83 e Å−3
S = 1.21Δρmin = −0.82 e Å−3
2390 reflectionsAbsolute structure: ?
174 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
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
N10.8952 (10)0.5770 (4)0.37825 (15)0.0157 (10)
C10.7282 (12)0.6745 (5)0.38778 (18)0.0154 (12)
H10.67590.73210.36470.018*
C20.6171 (12)0.6989 (5)0.43302 (17)0.0138 (12)
C30.4148 (12)0.8016 (5)0.44237 (18)0.0133 (12)
O10.3071 (9)0.8689 (3)0.40592 (12)0.0174 (9)
C40.1171 (13)0.9771 (4)0.41475 (18)0.0159 (12)
H4A−0.08260.95250.42960.024*
H4B0.06321.01920.38650.024*
H4C0.24061.03390.43420.024*
C50.3327 (12)0.8293 (5)0.48586 (18)0.0155 (12)
H50.20030.89940.49190.019*
C60.4459 (12)0.7535 (5)0.52094 (17)0.0138 (12)
O20.3510 (9)0.7888 (3)0.56290 (11)0.0167 (9)
C70.4941 (14)0.7232 (5)0.59995 (18)0.0222 (13)
H7A0.42700.63570.59890.033*
H7B0.42280.76070.62800.033*
H7C0.73040.72830.59840.033*
C80.6428 (12)0.6515 (5)0.51264 (17)0.0153 (12)
H80.71840.59990.53640.018*
C90.7263 (12)0.6267 (5)0.46874 (18)0.0160 (12)
H90.86340.55780.46290.019*
C101.0177 (13)0.5654 (6)0.33449 (18)0.0169 (13)
C111.1201 (12)0.6657 (5)0.30882 (18)0.0181 (13)
H111.09970.74810.32000.022*
C121.2516 (13)0.6466 (5)0.26700 (18)0.0179 (12)
H121.32670.71530.25010.022*
C131.2726 (12)0.5278 (5)0.25015 (18)0.0164 (13)
Br11.44896 (13)0.49899 (7)0.192736 (17)0.02466 (19)
C141.1702 (12)0.4254 (5)0.27488 (19)0.0172 (12)
H141.18660.34320.26330.021*
C151.0447 (13)0.4469 (6)0.31650 (18)0.0176 (13)
H150.97380.37790.33360.021*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.018 (2)0.013 (3)0.017 (2)0.000 (2)0.004 (2)−0.0016 (19)
C10.018 (3)0.011 (3)0.017 (3)−0.005 (2)0.002 (2)−0.003 (2)
C20.014 (3)0.009 (3)0.018 (3)−0.001 (2)0.003 (2)−0.002 (2)
C30.008 (3)0.013 (3)0.019 (3)0.000 (2)0.001 (2)−0.003 (2)
O10.020 (2)0.016 (2)0.016 (2)0.0038 (17)0.0036 (16)−0.0012 (16)
C40.022 (3)0.006 (3)0.021 (3)0.001 (2)0.002 (2)0.002 (2)
C50.015 (3)0.008 (3)0.024 (3)−0.003 (2)0.003 (2)−0.003 (2)
C60.016 (3)0.012 (3)0.014 (3)−0.006 (2)0.002 (2)−0.002 (2)
O20.023 (2)0.015 (2)0.012 (2)−0.0021 (17)0.0038 (16)−0.0013 (16)
C70.036 (3)0.015 (3)0.015 (3)−0.001 (3)0.004 (3)0.000 (2)
C80.017 (3)0.016 (3)0.013 (3)−0.002 (2)0.003 (2)0.006 (2)
C90.014 (3)0.012 (3)0.022 (3)−0.003 (2)0.001 (2)−0.003 (2)
C100.017 (3)0.020 (3)0.014 (3)0.003 (2)0.003 (2)−0.005 (2)
C110.018 (3)0.012 (3)0.024 (3)0.002 (2)0.003 (2)−0.002 (2)
C120.018 (3)0.014 (3)0.022 (3)−0.003 (2)0.007 (2)0.002 (2)
C130.014 (3)0.020 (4)0.016 (3)0.002 (2)0.006 (2)−0.005 (2)
Br10.0271 (3)0.0313 (3)0.0159 (3)0.0036 (3)0.0069 (2)−0.0002 (3)
C140.020 (3)0.009 (3)0.022 (3)0.002 (2)0.005 (2)−0.002 (2)
C150.022 (3)0.016 (3)0.014 (3)−0.005 (2)0.000 (3)0.003 (2)
Geometric parameters (Å, °) top
N1—C11.288 (7)C7—H7A0.9800
N1—C101.417 (7)C7—H7B0.9800
C1—C21.460 (7)C7—H7C0.9800
C1—H10.9500C8—C91.389 (7)
C2—C91.389 (7)C8—H80.9500
C2—C31.415 (7)C9—H90.9500
C3—O11.376 (6)C10—C151.387 (8)
C3—C51.383 (7)C10—C111.393 (8)
O1—C41.430 (6)C11—C121.388 (7)
C4—H4A0.9800C11—H110.9500
C4—H4B0.9800C12—C131.375 (7)
C4—H4C0.9800C12—H120.9500
C5—C61.402 (7)C13—C141.396 (7)
C5—H50.9500C13—Br11.902 (5)
C6—O21.375 (6)C14—C151.376 (8)
C6—C81.390 (7)C14—H140.9500
O2—C71.432 (6)C15—H150.9500
C1—N1—C10118.5 (5)O2—C7—H7C109.5
N1—C1—C2122.0 (5)H7A—C7—H7C109.5
N1—C1—H1119.0H7B—C7—H7C109.5
C2—C1—H1119.0C6—C8—C9118.4 (5)
C9—C2—C3117.9 (5)C6—C8—H8120.8
C9—C2—C1120.6 (5)C9—C8—H8120.8
C3—C2—C1121.3 (5)C2—C9—C8122.5 (5)
O1—C3—C5123.4 (5)C2—C9—H9118.7
O1—C3—C2115.9 (4)C8—C9—H9118.7
C5—C3—C2120.6 (5)C15—C10—C11117.9 (5)
C3—O1—C4116.9 (4)C15—C10—N1118.1 (5)
O1—C4—H4A109.5C11—C10—N1123.9 (5)
O1—C4—H4B109.5C12—C11—C10120.6 (5)
H4A—C4—H4B109.5C12—C11—H11119.7
O1—C4—H4C109.5C10—C11—H11119.7
H4A—C4—H4C109.5C13—C12—C11119.7 (5)
H4B—C4—H4C109.5C13—C12—H12120.1
C3—C5—C6119.7 (5)C11—C12—H12120.1
C3—C5—H5120.2C12—C13—C14121.0 (5)
C6—C5—H5120.2C12—C13—Br1120.6 (4)
O2—C6—C8123.9 (5)C14—C13—Br1118.3 (4)
O2—C6—C5115.2 (5)C15—C14—C13118.0 (5)
C8—C6—C5120.9 (5)C15—C14—H14121.0
C6—O2—C7116.8 (4)C13—C14—H14121.0
O2—C7—H7A109.5C14—C15—C10122.6 (5)
O2—C7—H7B109.5C14—C15—H15118.7
H7A—C7—H7B109.5C10—C15—H15118.7
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C7—H7A···N1i0.982.743.667 (7)159
C4—H4C···O2ii0.982.543.398 (6)145
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x+1, −y+2, −z+1.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C7—H7A···N1i0.982.743.667 (7)159
C4—H4C···O2ii0.982.543.398 (6)145
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x+1, −y+2, −z+1.
Acknowledgements top

We thank the University of Otago for purchase of the diffractometer.

references
References top

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