The synthesis of a novel benzimidazole derivative with a long-chain-ester substituent, namely methyl 8-[4-(1H-benzimidazol-2-yl)phenoxy]octanoate, (3), is reported. Ester (3) shows evidence of aggregation in solution and weak gelation ability with toluene. The octan-1-ol solvate, methyl 8-[4-(1H-benzimidazol-2-yl)phenoxy]octanoate octan-1-ol monosolvate, CHNO·CHO, (4), exhibits a four-molecule hydrogen-bonded motif in the solid state, with N-H...O hydrogen bonds between benzimidazole molecules and O-H...N hydrogen bonds between the octan-1-ol solvent molecules and the benzimidazole unit. The alkyl chains of the ester and the octan-1-ol molecules are in unfolded conformations. The phenylene ring is canted by 10.27 (6)° from the plane of the benzimidazole ring system. H...C contacts make up 20.7% of the Hirshfeld surface coverage. Weak C-H...π interactions involving the benzimidazole alkyl chain and three aromatic rings are observed.

The structures of three lead(II) coordination polymers are reported. One exhibits a two-dimensional structure, whereas the other two are one-dimensional. All three exhibit bidentate bridging acetate and monodentate benzene-1,2-di­amine ligands. The extended structures reveal extensive hydrogen-bonding networks involving the di­amine and acetate ligands.

Hydrogen-bonding interactions play an important role in the rational design of crystal systems with desirable architectures. The crystal structures of benzene-1,2-diaminium sulfate sesquihydrate, C6H20N2 2+·SO4 2−·1.5H2O, (1), benzene-1,3-diaminium tetrachloridozincate(II), (C6H20N2)[ZnCl4], (3), and 3-aminoanilinium perchlorate, C6H9N2 +·ClO4 −, (4), are reported. Hydrated salt (1) is a polymorph (space group C2/c) of a previously reported [Anderson et al. (2011). Cryst. Growth Des. 11, 4904–4919] crystalline modification of salt (2) (space group P21/c). The contents of the asymmetric unit of (2) are twice that of (1). In each, the extended structures exhibit hydrogen bonds, resulting in chains of ions and hydrogen-bonded rings with an R 4 4(8) motif involving water molecules. Hirshfeld surface analysis shows that a significant difference between the two is the degree of C...C interaction. Salt (3) exhibits an extended structure having hydrogen-bonded rings and parallel benzene rings, with a centroid-to-centroid separation of 3.860 (2) Å. Salt (4) displays a three-dimensional superstructure that results from linked planes of ions joined by an extensive hydrogen-bonding network involving N—H...O, N—H...N and C—H...π interactions. The cation–anion and N—H...N interaction energies in (4), determined using density functional theory (DFT), show significantly stronger aminium–perchlorate than amine–perchlorate interactions.

The structures of two zinc complexes containing bidentate benzene-1,2-di­amine ligands are reported. (Benzene-1,2-di­amine-κ2 N,N′)di­chloro­idozinc displays a distorted tetra­hedral geometry. The 1:1 co-crystal salt trans-di­aqua­bis­(4,5-di­methyl­benzene-1,2-di­amine- κ2 N,N′)zinc chloride 4,5-di­methyl­benzene-1,2-di­amine exhibits a tetra­gonally distorted octa­hedral zinc coordination sphere.