1-Chloro-4-[2-(4-chlorophenyl)ethyl]benzene and its bromo analogue: crystal structure, Hirshfeld surface analysis and computational chemistry

Abstract

The crystal and molecular structures of C14H12Cl2, (I), and C14H12Br2, (II), are described. The asymmetric unit of (I) comprises two independent molecules, A and B, each disposed about a centre of inversion. Each molecule approximates mirror symmetry [the Cb—Cb—Ce—Ce torsion angles = −83.46 (19) and 95.17 (17)° for A, and −83.7 (2) and 94.75 (19)° for B; b = benzene and e = ethylene]. By contrast, the molecule in (II) is twisted, as seen in the dihedral angle of 59.29 (11)° between the benzene rings cf. 0° in (I). The molecular packing of (I) features benzene-C—H...π(benzene) and Cl...Cl contacts that lead to an open three-dimensional (3D) architecture that enables twofold 3D–3D interpenetration. The presence of benzene-C—H...π(benzene) and Br...Br contacts in the crystal of (II) consolidate the 3D architecture. The analysis of the calculated Hirshfeld surfaces confirm the influence of the benzene-C—H...π(benzene) and X...X contacts on the molecular packing and show that, to a first approximation, H...H, C...H/H...C and C...X/X...C contacts dominate the packing, each contributing about 30% to the overall surface in each of (I) and (II). The analysis also clearly differentiates between the A and B molecules of (I).