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

Aliakbar Dehno Khalaji; Matthias Weil; Kazuma Gotoh; Hiroyuki Ishida

doi:10.1107/S1600536809003432

. 2009 Jan 31;65(Pt 2):o436. doi: 10.1107/S1600536809003432

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

Aliakbar Dehno Khalaji ^a,^‡, Matthias Weil ^b, Kazuma Gotoh ^c, Hiroyuki Ishida ^c,^*

PMCID: PMC2968382 PMID: 21582021

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 ▶). For structures containing a 4-bromoaniline unit, see: Khalaji et al. (2007 ▶); Khalaji & Harrison (2008 ▶).

Experimental

Crystal data

C₁₆H₁₆BrNO₃
M _r = 350.21
Monoclinic,
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 ▶) 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
Δρ_max = 0.30 e Å⁻³
Δρ_min = −0.53 e Å⁻³
Absolute structure: Flack (1983 ▶), 1511 Friedel pairs
Flack parameter: 0.012 (6)

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

Supplementary Material

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

e-65-0o436-sup1.cif^{(18.7KB, cif)}

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

e-65-0o436-Isup2.hkl^{(171.5KB, hkl)}

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—H7⋯O1ⁱ	0.93	2.63	3.272 (2)	127
C7—H7⋯O2ⁱ	0.93	2.63	3.553 (3)	172

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Symmetry code: (i) Inline graphic .

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.