Abstract
The title Br/Cl-substituted Schiff base, C
15
H
12
BrCl
2
NO
2
, was synthesized
via
condensation of 2,4-dichloroaniline with 3-bromo-4,5-dimethoxybenzaldehyde under mild acidic conditions. Its molecular and crystal structures were determined by single-crystal X-ray diffraction (monoclinic space group
C
2/
c
,
Z
= 8). Structurally, the molecule adopts a twisted conformation, with an angle of approximately 41.6 (4)° between the planes of the 3-bromo-4,5-dimethoxyphenyl and 2,4-dichlorophenyl moieties, a value significantly greater than those reported for related halogen-substituted Schiff bases in the literature, indicating a substantial disruption of the π-conjugated system across the azomethine bridge. The
E
configuration is confirmed, with a C=N bond length of 1.281 (3) Å, consistent with partial double-bond character resulting from the opposing electronic effects of the methoxy donors and the halogen withdrawing groups. In the crystal, intermolecular C—H...Cl and C—H...Br contacts of 2.96 and 3.04 Å, respectively, compared to the van der Waals sums of 2.95 and 3.05 Å, link molecules into supramolecular chains along the
a
axis, demonstrating that the twisted molecular geometry, imposed by halogen substitution, directly governs the three-dimensional crystal packing. Hirshfeld surface analysis confirms that halogen-involving interactions collectively account for 32% of the total surface area (Cl...H/H...Cl = 20% and Br...H/H...Br = 12%), ranking them among the most significant contributors to supramolecular stabilization alongside H...H (27%), C...H/H...C (12.1%) and O...H/H...O (5.2%) contacts. Finally, energy framework calculations indicate that dispersion interactions dominate the stabilization of the crystal structure, thus highlighting the key role of weak van der Waals forces in the supramolecular assembly.