Crystal structure of N-(p-methylbenzylidene)-p-bromoaniline

Article abstract of DOI:10.1134/S0022476617020226

The asymmetric unit of the title compound C₁₄H₁₂BrN (systematic name (E)-N-(4-bromophenyl)-1-(p-tolyl)methanimine) contains one half-molecule: a crystallographic center of inversion is located at the midpoint of the bridging N=C bond. The central HC=N unit makes dihedral angles of 15.7(3)° and 15.2(4)° with bromobenzene and methylbenzene ring systems, respectively. The C and N atoms of the HC=N central unit are disordered over two sites in a 50:50 ratio. The Br atom of the 4-bromoaniline ring and the methyl atom of the 4-methylbenzilidene ring systems are also 50% disordered. In the crystal, molecules are linked by C–H?π interactions forming slabs parallel to the bc plane. The atomic coordinates are not available for the previously reported crystal structure of the title compound: CSD refcode MBZCLE. The reported R factor of 0.103 for the analysis in the space group P2₁/a is much higher than in the present analysis, which gives 0.033 in the space group P2₁/c.

Full text of DOI:10.1134/S0022476617020226

Journal of Structural Chemistry. Vol. 58, No. 2, pp. 370-372, 2017.
Original Russian Text © 2017 L. Jothi, G. Anuradha, G. Vasuki, R. Ramesh Babu, K. Ramamurthi.
CRYSTAL STRUCTURE
OF N-(p-METHYLBENZYLIDENE)-p-BROMOANILINE
1
L. Jothi , G. Anuradha *, G. Vasuki **,
2
2
UDC 541.6:547.021
3
R. Ramesh Babu , and K. Ramamurthi
4
The asymmetric unit of the title compound C14H12BrN (systematic name (E)-N-(4-bromophenyl)-
1-(p-tolyl)methanimine) contains one half-molecule: a crystallographic center of inversion is located at the
midpoint of the bridging N=C bond. The central HC=N unit makes dihedral angles of 15.7(3)° and 15.2(4)°
with bromobenzene and methylbenzene ring systems, respectively. The C and N atoms of the HC=N
central unit are disordered over two sites in a 50:50 ratio. The Br atom of the 4-bromoaniline ring and the
methyl atom of the 4-methylbenzilidene ring systems are also 50% disordered. In the crystal, molecules are
linked by C–H⋯π interactions forming slabs parallel to the bc plane. The atomic coordinates are not
available for the previously reported crystal structure of the title compound: CSD refcode MBZCLE. The
reported R factor of 0.103 for the analysis in the space group P21/a is much higher than in the present
analysis, which gives 0.033 in the space group P21/c.
DOI: 10.1134/S0022476617020226
Keywords: synthesis, crystal structure, benzylidene, aniline, hydrogen bonding.
Schiff base ligands exhibit many pharmaceutical activities, such as antifungal and antibacterial, radical scavenging
effect, enzyme activity inhibition [1-4]. As a continuation of our work on the synthesis and structural characterization of
Schiff base compounds [5-8], herein we report the crystal structure of the title compound.
Experimental. Synthesis and crystallization. The title compound was synthesized from 4-methylbenzaldehyde and
4-bromoaniline by the condensation method. The reaction mixture was refluxed in ethanol for about 8 h and the resulting
solution was slowly evaporated at room temperature. After 15 days, colorless block-like crystals of the title compound,
suitable for the X-ray crystallographic analysis, were obtained.
Scheme 1.
X-ray crystallography. For the crystal structure determination the single crystal of the C14H12BrN compound was
used for data collection on a Bruker Kappa APEX II CCD diffractometer [9] using MoK radiation (λ = 0.71073 Å), and
α
1
2
Department of Physics, NKR Government Arts College for Women, Namakkal, India. Department of Physics,
Kunthavai Naachiar Government Arts College (W) (Autonomous), Thanjavur, India; *sai.anuradha@yahoo.com,
3
**vasuki.arasi@yahoo.com. Crystal Growth and Thin Film Laboratory, School of Physics, Bharathidasan University,
4
Tiruchirappalli, India. Department of Physics and Nanotechnology, Faculty of Engineering and Technology, SRM University,
Kattankulathur, Kanchipuram, India. The text was submitted by the authors in English. Zhurnal Strukturnoi Khimii, Vol. 58,
No. 2, pp. 387-389, February-March, 2017. Original article submitted October 24, 2015; revised December 3, 2015.
370
0022-4766/17/5802-0370 © 2017 by Pleiades Publishing, Ltd.

TABLE 1. Hydrogen Bond Geometry (Å, deg)
D–H⋯A
H⋯A
D⋯A
D–H⋯A
D–H
i
C2–H2⋯Cg1
0.93
0.93
2.82
2.87
3.530(2)
3.600(2)
134
136
ii
C5–H5⋯Cg1
i ii
Cg1 is the centroid of the C1–C6 benzene ring; symmetry codes: x, –y+1/2, z+1/2; x, –y–1/2, z–1/2.
a multiscan absorption correction was applied using SADABS [9]. The lattice parameters were determined by the least
squares technique using SAINT Plus [9]. The structure was solved by direct methods using SHELXS97 [10] and refined
using full-matrix least squares procedures (SHELXL97) [10]. All non-hydrogen atoms were refined anisotropically and all
hydrogen atoms bound to carbon were placed in the calculated positions, and their thermal parameters were refined
isotropically with Uiso(H) = 1.2-1.5 Ueq(C). Molecular plots and packing diagrams were produced using Mercury [11] along
with the other material for publication produced using the WinGX publication routines [12]. Intermolecular C–H⋯π
interactions are given in Table 1.
Crystallographic characteristics of C14H12BrN: FW = 274.16, a = 13.8666(17) Å, b = 7.4071(9) Å, c = 5.9609(8) Å,
3
β = 99.718(5)°, V = 603.47(13) Å , P21/c, Z = 2, dcalc = 1.509 g/cm , μ = 3.337 mm , 2.98° < θ < 25.99°, 1057 I were
3
–1
hkl
measured, out of which 1057 were independent (Rint = 0.0000), 736 I with I > 2σ , 92 refined parameters; GOOF = 1.01;
hkl I
R1 = 0.0325, wR2 = 0.0745 for I > 2σ ; R1 = 0.0593, wR2 = 0.0846 for all I ; the residual electron density (max/min)
I hkl
3
0.146/–0.178 e/Å .
Results and discussion. The title compound adopts an E conformation with respect to the N1=C7 bond. The
asymmetric unit of the title compound (Fig. 1) contains one-half molecule. A crystallographic centre of inversion is located at
Fig. 1. Molecular structure of the title compound with atom labeling.
Displacement ellipsoids are drawn at the 50% probability level.
Fig. 2. A view along the c axis of the crystal packing
of the title compound.The C–H⋯π contacts are
represented by dashed lines and the involved H atoms
as grey balls (Table 1). H atoms not involved in these
interactions have been omitted for clarity.
371

the midpoint of the bridging N1=C7 bond. Both C7 and N1 atoms of this central bond are 50% disordered. The central HC=N
unit makes dihedral angles of 15.7(3)° and 15.2(4)° with the 4-bromobenzene and 4-methylbenzene ring systems,
respectively. The Br1 atom of the 4-bromoaniline ring and the C8 atom of the 4-methylbenzylidene ring are also 50%
disordered. The experimental details are given in Table 1.
In the crystal, molecules are linked by C–H⋯π interactions forming slabs parallel to the bc plane (Table 1 and
Fig. 2). The atomic coordinates are not available for the previously reported crystal structure of the title compound: CSD [13]
refcode MBZCLE [14]. The reported R factor of 0.103 for the analysis in the space group P21/a, is much higher than in the
present analysis which gives R = 0.033 in the space group P21/c.
The authors thank the Sophisticated Analytical Instrument Facility, IIT-Madras, Chennai-36 for the single crystal
X-ray data collection.
Supplementary material. CCDC-924041 for the compound discussed contains the supplementary crystallographic
data for this paper. These data can be obtained free of charge at http://www.ccdc.cam.ac.uk/const/retrieving.html or from the
Cambridge Crystallographic Data Centre (CCDC), 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44(0)1223-336033 or
e-mail: data_request@ccdc.cam.ac.uk.
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