Structure of the mercury(II) mixed-halide (Br/Cl) complex of 2,2'-(5-tert-butyl-1,3-phenyl-ene)bis-(1-pentyl-1H-benzo[d]imidazole).

The mercury(II) complex of 2,2'-(5-tert-butyl-1,3-phenyl-ene)bis-(1-pentyl-1H-benz-imidazole), namely catena-poly[[dihalogenido-mercury(II)]-μ-2,2'-(5-tert-butyl-1,3-phenyl-ene)bis-(1-pentyl-1H-benzimidazole)-κ(2)N(3):N(3')], [HgBr(1.52)Cl(0.48)(C(34)H(42)N(4))], 2, has a polymeric structure bridging via the N atoms from the benzimidazole moieties of the ligand. The compound crystallizes in the ortho-rhom-bic space group Pca2(1) and is a racemic twin [BASF = 0.402†(9)]. The geometry around the Hg(II) atom is distorted tetra-hedral, with the Hg(II) atom coordinated to two N atoms, one Br atom, and a fourth coordination site is occupied by a mixed halide (Br/Cl). For the two ligands in the asymmetric unit, there is disorder with one of the two tert-butyl groups and benzimidazole moieties showing twofold disorder, with occupancy factors of 0.57†(2):0.43†(2) for the tert-butyl group and 0.73†(3):0.27†(3) for the benzimidazole group. In addition, there is threefold disorder for two of the four n-pentyl groups, with occupancy factors of 0.669†(4):0.177†(4):0.154†(4) and 0.662†(4):0.224†(4):0.154†(4), respectively. The mol-ecules form a one-dimensional helical polymer propagating in the b-axis direction. The helices are held together by intra-strand C-H⋯Br and C-H⋯Cl inter-actions. Each strand is further linked by inter-strand C-H⋯Br and C-H⋯Cl inter-actions. In addition, there are weak C-H⋯N inter-strand inter-actions which further stabilize the structural arrangement.