N-(4-Bromo­benzyl­idene)-4-methoxy­aniline

In the title compound, C₁₄H₁₂BrNO, the torsion angle about the central C=N double bond is 170.4 (3)° and the dihedral angle between the aromatic rings is 9.6 (3)°.

Key indicators

• Single-crystal X-ray study
• T = 292 K
• Mean [sigma](C-C) = 0.009 Å
• R factor = 0.064
• wR factor = 0.121
• Data-to-parameter ratio = 15.1

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low .......       0.96
PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical .          ?
PLAT341_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ...          9
PLAT431_ALERT_2_C Short Inter HL..A Contact  Br1    ..  O1      ..       3.13 Ang.

Alert level G
REFLT03_ALERT_4_G  WARNING: Large fraction of Friedel related reflns may
                     be needed to determine absolute structure
           From the CIF: _diffrn_reflns_theta_max           28.28
           From the CIF: _reflns_number_total               2349
           Count of symmetry unique reflns         1585
           Completeness (_total/calc)            148.20%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured       764
           Fraction of Friedel pairs measured     0.482
           Are heavy atom types Z>Si present        yes
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          1

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   4 ALERT level C = Check and explain
   2 ALERT level G = General alerts; check

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   3 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

Schiff bases such as those derived from salicylaldehyde and aniline are readily synthesized. The Schiff base of N-(4-Bromobenzylidene)-3-nitroaniline had been reported before (Sun et al., 2006). As part of a project to examine the catalytic activity of Schiff bases that in the form of their nickel complexes (Gao et al., 2004), the title p-bromobenzaldehyde derivative, (I), was obtained by reaction with 4-methoxyaniline (Fig. 1). The molecule is not planar as the two aromatic rings are twisted about the double bond in order to relieve steric strain.

Related literature

For related literature, see: Gao et al. (2004); Sun et al. (2006).

S2. Experimental

p-Methoxyaniline (2.24 g, 18.2 mmol) and p-bromobenzaldehyde (3.33 g, 18.0 mmol) were dissolved in ethanol (35 ml) along with 1 ml of formic acid. The solution was refluxed for 8 h. Removal of the solvent followed by recrystallization from a 1:1 v/v ethanol/dichloromethane mixture (35 ml) gave the title compound in about 70% yield. Colourless blocks of (I) were grown from ethanol. Elemental analysis: calculated for C₁₄H₁₂Br₁N₁O₁: C 57.95, H 4.17, N 4.83%; found: C 57.80, H 4.01, N 5.02%.

S3. Refinement

The H atoms were placed in calculated positions (C—H = 0.93 Å) and refined as riding with U_iso(H) = 1.2U_eq(C).

Computing details

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT (Bruker, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1997); software used to prepare material for publication: SHELXTL (Bruker, 1997).

Figures

Fig. 1. Vew of (I), with displacement ellipsoids drawn at the 50% probability level. The H atoms are drawn as spheres of arbitrary radius.

N-(4-Bromobenzylidene)-4-methoxyaniline

Crystal data

C14H12BrNO	F(000) = 584
Mr = 290.15	Dx = 1.543 Mg m^−3
Orthorhombic, Pca21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2ac	Cell parameters from 1585 reflections
a = 6.1510 (8) Å	θ = 2.1–28.3°
b = 7.2726 (9) Å	µ = 3.27 mm^−1
c = 27.914 (4) Å	T = 292 K
V = 1248.7 (3) Å^3	Block, colorless
Z = 4	0.10 × 0.10 × 0.06 mm

Data collection

Bruker SMART CCD diffractometer	2349 independent reflections
Radiation source: fine-focus sealed tube	1512 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.063
ω scans	θmax = 28.3°, θmin = 2.8°
Absorption correction: multi-scan (SADABS; Bruker, 1997)	h = −7→7
Tmin = 0.728, Tmax = 0.822	k = −9→7
8336 measured reflections	l = −26→36

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.064	H-atom parameters constrained
wR(F^2) = 0.121	w = 1/[σ^2(Fo^2) + (0.0415P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.06	(Δ/σ)max = 0.005
2349 reflections	Δρmax = 0.51 e Å^−3
156 parameters	Δρmin = −0.32 e Å^−3
1 restraint	Absolute structure: Flack (1983), 764 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.016 (18)

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
Br1	−0.03907 (11)	0.72700 (9)	0.51664 (4)	0.0716 (3)
C1	0.2243 (10)	0.7455 (7)	0.3597 (2)	0.0396 (15)
C2	0.3529 (11)	0.8085 (8)	0.3978 (3)	0.0467 (16)
H2	0.4926	0.8518	0.3919	0.056*
C3	0.2744 (11)	0.8067 (9)	0.4438 (3)	0.0530 (17)
H3	0.3583	0.8526	0.4688	0.064*
C4	0.0688 (12)	0.7360 (8)	0.4527 (3)	0.0497 (17)
C5	−0.0597 (10)	0.6762 (8)	0.4166 (2)	0.0468 (16)
H5	−0.1985	0.6318	0.4230	0.056*
C6	0.0186 (11)	0.6820 (12)	0.3697 (3)	0.049 (2)
H6	−0.0700	0.6423	0.3447	0.059*
C7	0.3079 (11)	0.7367 (8)	0.3107 (3)	0.0463 (16)
H7	0.2108	0.7099	0.2862	0.056*
C8	0.5757 (9)	0.7501 (6)	0.2515 (2)	0.0350 (14)
C9	0.7727 (8)	0.8355 (7)	0.2403 (2)	0.0356 (14)
H9	0.8507	0.8937	0.2645	0.043*
C10	0.8535 (9)	0.8355 (7)	0.1949 (2)	0.0388 (14)
H10	0.9833	0.8956	0.1880	0.047*
C11	0.7415 (9)	0.7457 (7)	0.1590 (2)	0.0342 (13)
C12	0.5511 (10)	0.6601 (10)	0.1690 (2)	0.0375 (16)
H12	0.4771	0.6001	0.1446	0.045*
C13	0.4639 (9)	0.6596 (7)	0.2147 (2)	0.0381 (14)
H13	0.3331	0.6000	0.2209	0.046*
C14	1.0077 (11)	0.8162 (12)	0.0993 (3)	0.068 (2)
H14A	0.9931	0.9475	0.1005	0.102*
H14B	1.0472	0.7797	0.0674	0.102*
H14C	1.1186	0.7777	0.1213	0.102*
N1	0.5029 (8)	0.7632 (7)	0.3001 (2)	0.0428 (13)
O1	0.8083 (7)	0.7336 (5)	0.11189 (16)	0.0498 (12)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.0775 (5)	0.0926 (6)	0.0447 (4)	−0.0006 (3)	0.0177 (5)	−0.0023 (8)
C1	0.043 (4)	0.036 (4)	0.040 (4)	0.009 (3)	0.000 (3)	0.004 (3)
C2	0.038 (4)	0.050 (4)	0.052 (4)	−0.003 (3)	−0.004 (3)	0.003 (3)
C3	0.059 (5)	0.059 (4)	0.042 (4)	−0.011 (3)	−0.007 (3)	−0.004 (3)
C4	0.070 (5)	0.040 (4)	0.040 (4)	−0.002 (3)	0.012 (3)	−0.002 (3)
C5	0.043 (4)	0.049 (4)	0.049 (4)	−0.006 (3)	0.009 (3)	0.004 (3)
C6	0.041 (4)	0.055 (5)	0.052 (6)	−0.001 (3)	−0.012 (4)	−0.006 (4)
C7	0.048 (4)	0.045 (4)	0.046 (4)	−0.002 (3)	−0.007 (3)	−0.003 (3)
C8	0.038 (3)	0.024 (3)	0.043 (4)	0.003 (2)	−0.002 (3)	0.008 (3)
C9	0.033 (3)	0.035 (3)	0.039 (4)	0.002 (2)	−0.008 (3)	0.000 (3)
C10	0.032 (3)	0.032 (3)	0.052 (4)	−0.005 (2)	0.001 (3)	−0.004 (3)
C11	0.036 (3)	0.035 (3)	0.032 (3)	0.013 (3)	−0.003 (3)	0.005 (3)
C12	0.032 (3)	0.044 (4)	0.037 (4)	−0.005 (3)	−0.001 (3)	−0.006 (3)
C13	0.032 (3)	0.035 (3)	0.047 (4)	−0.008 (2)	0.003 (3)	0.000 (3)
C14	0.055 (5)	0.106 (6)	0.043 (5)	−0.005 (4)	0.004 (3)	0.014 (4)
N1	0.042 (3)	0.047 (3)	0.039 (3)	−0.007 (2)	−0.003 (2)	0.005 (2)
O1	0.048 (3)	0.063 (3)	0.039 (3)	−0.0046 (19)	0.003 (2)	0.004 (2)

Geometric parameters (Å, º)

Br1—C4	1.905 (7)	C8—C13	1.400 (9)
C1—C6	1.376 (9)	C8—N1	1.431 (9)
C1—C2	1.404 (9)	C9—C10	1.363 (7)
C1—C7	1.461 (9)	C9—H9	0.9300
C2—C3	1.370 (9)	C10—C11	1.379 (8)
C2—H2	0.9300	C10—H10	0.9300
C3—C4	1.388 (9)	C11—C12	1.356 (8)
C3—H3	0.9300	C11—O1	1.381 (7)
C4—C5	1.352 (10)	C12—C13	1.383 (9)
C5—C6	1.397 (10)	C12—H12	0.9300
C5—H5	0.9300	C13—H13	0.9300
C6—H6	0.9300	C14—O1	1.411 (8)
C7—N1	1.251 (8)	C14—H14A	0.9600
C7—H7	0.9300	C14—H14B	0.9600
C8—C9	1.397 (7)	C14—H14C	0.9600
C6—C1—C2	118.3 (7)	C10—C9—C8	121.6 (6)
C6—C1—C7	119.9 (6)	C10—C9—H9	119.2
C2—C1—C7	121.7 (6)	C8—C9—H9	119.2
C3—C2—C1	120.6 (7)	C9—C10—C11	119.6 (5)
C3—C2—H2	119.7	C9—C10—H10	120.2
C1—C2—H2	119.7	C11—C10—H10	120.2
C2—C3—C4	119.5 (7)	C12—C11—C10	119.9 (6)
C2—C3—H3	120.2	C12—C11—O1	115.1 (6)
C4—C3—H3	120.2	C10—C11—O1	124.9 (5)
C5—C4—C3	121.2 (7)	C11—C12—C13	121.8 (6)
C5—C4—Br1	118.9 (5)	C11—C12—H12	119.1
C3—C4—Br1	119.9 (6)	C13—C12—H12	119.1
C4—C5—C6	119.2 (6)	C12—C13—C8	119.0 (5)
C4—C5—H5	120.4	C12—C13—H13	120.5
C6—C5—H5	120.4	C8—C13—H13	120.5
C1—C6—C5	121.2 (7)	O1—C14—H14A	109.5
C1—C6—H6	119.4	O1—C14—H14B	109.5
C5—C6—H6	119.4	H14A—C14—H14B	109.5
N1—C7—C1	123.6 (6)	O1—C14—H14C	109.5
N1—C7—H7	118.2	H14A—C14—H14C	109.5
C1—C7—H7	118.2	H14B—C14—H14C	109.5
C9—C8—C13	118.2 (6)	C7—N1—C8	121.0 (6)
C9—C8—N1	116.9 (5)	C11—O1—C14	118.0 (5)
C13—C8—N1	124.9 (5)