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

Abstract

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.

Related literature

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

Crystal data

• C₁₅H₁₄BrNO₂

• M _r = 320.18

• Monoclinic,

• a = 4.1323 (6) Å

• b = 10.7406 (14) Å

• c = 29.911 (4) Å

• β = 90.992 (8)°

• V = 1327.4 (3) ų

• Z = 4

• Mo Kα radiation

• μ = 3.09 mm⁻¹

• T = 89 K

• 0.25 × 0.10 × 0.02 mm

Data collection

• Bruker APEXII CCD area-detector diffractometer

• Absorption correction: multi-scan (SADABS; Bruker, 2006 ▶) T _min = 0.570, T _max = 0.940

• 13728 measured reflections

• 2390 independent reflections

• 1664 reflections with I > 2σ(I)

• R _int = 0.106

Refinement

• R[F ² > 2σ(F ²)] = 0.056

• wR(F ²) = 0.118

• S = 1.21

• 2390 reflections

• 174 parameters

• H-atom parameters constrained

• Δρ_max = 0.83 e Å⁻³

• Δρ_min = −0.82 e Å⁻³

Data collection: APEX2 (Bruker, 2006 ▶); cell refinement: APEX2 and SAINT (Bruker, 2006 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶) and TITAN2000 (Hunter & Simpson, 1999 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶) and Mercury (Macrae et al., 2006 ▶); software used to prepare material for publication: SHELXL97, enCIFer (Allen et al., 2004 ▶), PLATON (Spek, 2009 ▶) and publCIF (Westrip, 2009 ▶).

Supplementary Material

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C7—H7A⋯N1i	0.98	2.74	3.667 (7)	159
C4—H4C⋯O2ii	0.98	2.54	3.398 (6)	145

Symmetry codes: (i) ; (ii) .

supplementary crystallographic information

Comment

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.

Experimental

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

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

Figures

Fig. 1.

The structure of (I) with displacement ellipsoids for the non-hydrogen atoms drawn at the 50% probability level.

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.

Crystal data

C15H14BrNO2	F(000) = 648
Mr = 320.18	Dx = 1.602 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 2351 reflections
a = 4.1323 (6) Å	θ = 2.7–23.6°
b = 10.7406 (14) Å	µ = 3.09 mm−1
c = 29.911 (4) Å	T = 89 K
β = 90.992 (8)°	Rectangular plate, pale yellow
V = 1327.4 (3) Å3	0.25 × 0.10 × 0.02 mm
Z = 4

Data collection

Bruker APEXII CCD area-detector diffractometer	2390 independent reflections
Radiation source: fine-focus sealed tube	1664 reflections with I > 2σ(I)
graphite	Rint = 0.106
ω scans	θmax = 25.3°, θmin = 2.0°
Absorption correction: multi-scan (SADABS; Bruker, 2006)	h = −3→4
Tmin = 0.570, Tmax = 0.940	k = −12→12
13728 measured reflections	l = −35→35

Refinement

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.056	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.118	H-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 parameters	Δρmax = 0.83 e Å−3
0 restraints	Δρmin = −0.82 e Å−3

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 (Ų)

	x	y	z	Uiso*/Ueq
N1	0.8952 (10)	0.5770 (4)	0.37825 (15)	0.0157 (10)
C1	0.7282 (12)	0.6745 (5)	0.38778 (18)	0.0154 (12)
H1	0.6759	0.7321	0.3647	0.018*
C2	0.6171 (12)	0.6989 (5)	0.43302 (17)	0.0138 (12)
C3	0.4148 (12)	0.8016 (5)	0.44237 (18)	0.0133 (12)
O1	0.3071 (9)	0.8689 (3)	0.40592 (12)	0.0174 (9)
C4	0.1171 (13)	0.9771 (4)	0.41475 (18)	0.0159 (12)
H4A	−0.0826	0.9525	0.4296	0.024*
H4B	0.0632	1.0192	0.3865	0.024*
H4C	0.2406	1.0339	0.4342	0.024*
C5	0.3327 (12)	0.8293 (5)	0.48586 (18)	0.0155 (12)
H5	0.2003	0.8994	0.4919	0.019*
C6	0.4459 (12)	0.7535 (5)	0.52094 (17)	0.0138 (12)
O2	0.3510 (9)	0.7888 (3)	0.56290 (11)	0.0167 (9)
C7	0.4941 (14)	0.7232 (5)	0.59995 (18)	0.0222 (13)
H7A	0.4270	0.6357	0.5989	0.033*
H7B	0.4228	0.7607	0.6280	0.033*
H7C	0.7304	0.7283	0.5984	0.033*
C8	0.6428 (12)	0.6515 (5)	0.51264 (17)	0.0153 (12)
H8	0.7184	0.5999	0.5364	0.018*
C9	0.7263 (12)	0.6267 (5)	0.46874 (18)	0.0160 (12)
H9	0.8634	0.5578	0.4629	0.019*
C10	1.0177 (13)	0.5654 (6)	0.33449 (18)	0.0169 (13)
C11	1.1201 (12)	0.6657 (5)	0.30882 (18)	0.0181 (13)
H11	1.0997	0.7481	0.3200	0.022*
C12	1.2516 (13)	0.6466 (5)	0.26700 (18)	0.0179 (12)
H12	1.3267	0.7153	0.2501	0.022*
C13	1.2726 (12)	0.5278 (5)	0.25015 (18)	0.0164 (13)
Br1	1.44896 (13)	0.49899 (7)	0.192736 (17)	0.02466 (19)
C14	1.1702 (12)	0.4254 (5)	0.27488 (19)	0.0172 (12)
H14	1.1866	0.3432	0.2633	0.021*
C15	1.0447 (13)	0.4469 (6)	0.31650 (18)	0.0176 (13)
H15	0.9738	0.3779	0.3336	0.021*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
N1	0.018 (2)	0.013 (3)	0.017 (2)	0.000 (2)	0.004 (2)	−0.0016 (19)
C1	0.018 (3)	0.011 (3)	0.017 (3)	−0.005 (2)	0.002 (2)	−0.003 (2)
C2	0.014 (3)	0.009 (3)	0.018 (3)	−0.001 (2)	0.003 (2)	−0.002 (2)
C3	0.008 (3)	0.013 (3)	0.019 (3)	0.000 (2)	0.001 (2)	−0.003 (2)
O1	0.020 (2)	0.016 (2)	0.016 (2)	0.0038 (17)	0.0036 (16)	−0.0012 (16)
C4	0.022 (3)	0.006 (3)	0.021 (3)	0.001 (2)	0.002 (2)	0.002 (2)
C5	0.015 (3)	0.008 (3)	0.024 (3)	−0.003 (2)	0.003 (2)	−0.003 (2)
C6	0.016 (3)	0.012 (3)	0.014 (3)	−0.006 (2)	0.002 (2)	−0.002 (2)
O2	0.023 (2)	0.015 (2)	0.012 (2)	−0.0021 (17)	0.0038 (16)	−0.0013 (16)
C7	0.036 (3)	0.015 (3)	0.015 (3)	−0.001 (3)	0.004 (3)	0.000 (2)
C8	0.017 (3)	0.016 (3)	0.013 (3)	−0.002 (2)	0.003 (2)	0.006 (2)
C9	0.014 (3)	0.012 (3)	0.022 (3)	−0.003 (2)	0.001 (2)	−0.003 (2)
C10	0.017 (3)	0.020 (3)	0.014 (3)	0.003 (2)	0.003 (2)	−0.005 (2)
C11	0.018 (3)	0.012 (3)	0.024 (3)	0.002 (2)	0.003 (2)	−0.002 (2)
C12	0.018 (3)	0.014 (3)	0.022 (3)	−0.003 (2)	0.007 (2)	0.002 (2)
C13	0.014 (3)	0.020 (4)	0.016 (3)	0.002 (2)	0.006 (2)	−0.005 (2)
Br1	0.0271 (3)	0.0313 (3)	0.0159 (3)	0.0036 (3)	0.0069 (2)	−0.0002 (3)
C14	0.020 (3)	0.009 (3)	0.022 (3)	0.002 (2)	0.005 (2)	−0.002 (2)
C15	0.022 (3)	0.016 (3)	0.014 (3)	−0.005 (2)	0.000 (3)	0.003 (2)

Geometric parameters (Å, °)

N1—C1	1.288 (7)	C7—H7A	0.9800
N1—C10	1.417 (7)	C7—H7B	0.9800
C1—C2	1.460 (7)	C7—H7C	0.9800
C1—H1	0.9500	C8—C9	1.389 (7)
C2—C9	1.389 (7)	C8—H8	0.9500
C2—C3	1.415 (7)	C9—H9	0.9500
C3—O1	1.376 (6)	C10—C15	1.387 (8)
C3—C5	1.383 (7)	C10—C11	1.393 (8)
O1—C4	1.430 (6)	C11—C12	1.388 (7)
C4—H4A	0.9800	C11—H11	0.9500
C4—H4B	0.9800	C12—C13	1.375 (7)
C4—H4C	0.9800	C12—H12	0.9500
C5—C6	1.402 (7)	C13—C14	1.396 (7)
C5—H5	0.9500	C13—Br1	1.902 (5)
C6—O2	1.375 (6)	C14—C15	1.376 (8)
C6—C8	1.390 (7)	C14—H14	0.9500
O2—C7	1.432 (6)	C15—H15	0.9500
C1—N1—C10	118.5 (5)	O2—C7—H7C	109.5
N1—C1—C2	122.0 (5)	H7A—C7—H7C	109.5
N1—C1—H1	119.0	H7B—C7—H7C	109.5
C2—C1—H1	119.0	C6—C8—C9	118.4 (5)
C9—C2—C3	117.9 (5)	C6—C8—H8	120.8
C9—C2—C1	120.6 (5)	C9—C8—H8	120.8
C3—C2—C1	121.3 (5)	C2—C9—C8	122.5 (5)
O1—C3—C5	123.4 (5)	C2—C9—H9	118.7
O1—C3—C2	115.9 (4)	C8—C9—H9	118.7
C5—C3—C2	120.6 (5)	C15—C10—C11	117.9 (5)
C3—O1—C4	116.9 (4)	C15—C10—N1	118.1 (5)
O1—C4—H4A	109.5	C11—C10—N1	123.9 (5)
O1—C4—H4B	109.5	C12—C11—C10	120.6 (5)
H4A—C4—H4B	109.5	C12—C11—H11	119.7
O1—C4—H4C	109.5	C10—C11—H11	119.7
H4A—C4—H4C	109.5	C13—C12—C11	119.7 (5)
H4B—C4—H4C	109.5	C13—C12—H12	120.1
C3—C5—C6	119.7 (5)	C11—C12—H12	120.1
C3—C5—H5	120.2	C12—C13—C14	121.0 (5)
C6—C5—H5	120.2	C12—C13—Br1	120.6 (4)
O2—C6—C8	123.9 (5)	C14—C13—Br1	118.3 (4)
O2—C6—C5	115.2 (5)	C15—C14—C13	118.0 (5)
C8—C6—C5	120.9 (5)	C15—C14—H14	121.0
C6—O2—C7	116.8 (4)	C13—C14—H14	121.0
O2—C7—H7A	109.5	C14—C15—C10	122.6 (5)
O2—C7—H7B	109.5	C14—C15—H15	118.7
H7A—C7—H7B	109.5	C10—C15—H15	118.7

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
C7—H7A···N1i	0.98	2.74	3.667 (7)	159
C4—H4C···O2ii	0.98	2.54	3.398 (6)	145

Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x+1, −y+2, −z+1.