3,3′-[1,2-Phenylenebis(methylene)]bis(1-propylbenzimidazolium) dibromide hemihydrate

The asymmetric unit of the title compound, C28H32N42+·2Br ·0.5H2O, contains one 3,3′-[1,2-phenylenebis(methylene)]bis(1-propylbenzimidazolium) cation, two bromide anions and one half-molecule of water. In the crystal, the whole 3,3′-[1,2-phenylenebis(methylene)]bis(1-propylbenzimidazolium) cation and one of the bromide anions are each disordered over two positions with site-occupancy ratios of 0.751 (6):0.249 (6) and 0.680 (8):0.320 (8). For the major component of the disordered cation, the central benzene ring forms dihedral angles of 83.6 (5) and 88.2 (4)° with its adjacent imidazole rings, while these angles for the minor component are 89.2 (15) and 84.9 (13)°. In the crystal, the cations and anions are linked by C—H...Br hydrogen bonds into dimers and then stacked along the c axis. The crystal packing is further stabilized by C—H...π and π–π interactions [shortest centroid–centroid distance = 3.646 (4) ].