Charge-assisted hydrogen bonding in three diaminobenzene salts.

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, C6H20N22+·SO42-·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 R44(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.

Synthesis and characterization of a novel long-alkyl-chain ester-substituted benzimidazole gelator and its octan-1-ol solvate.

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, C22H26N2O3·C8H18O, (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.

Structural characterization of two benzene-1,2-di-amine complexes of zinc chloride: a mol-ecular compound and a co-crystal salt.

The structures of two zinc complexes containing bidentate benzene-1,2-di-amine ligands are reported. (Benzene-1,2-di-amine-κ(2) N,N')di-chloro-idozinc, [ZnCl2(C6H8N2)], (I), displays a distorted tetra-hedral coordination sphere for the metal cation. The di-amine ligand and the Zn atom reside on a crystallographic mirror plane. In the 1:1 co-crystal salt trans-di-aqua-bis-(4,5-di-methyl-benzene-1,2-di-amine-κ(2) N,N')zinc chloride-4,5-di-methyl-benzene-1,2-di-amine (1/1), [Zn(C8H12N2)2(H2O)2]Cl2·2C8H12N2, (II), the zinc(II) complex cation exhibits a tetra-gonally distorted octa-hedral coordination sphere. The Zn atom sits on a crystallographically imposed inversion center and the di-amine ligands are tilted 30.63 (6)° with respect to the ZnN4 plane. Both complexes exhibit extensive hydrogen bonding. In (I), a stacked-sheet extended structure parallel to (101) is observed. In (II), the co-crystallized di-amine is hydrogen-bonded to the complex cation via O-H⋯N and N-H⋯N linkages. These units are in turn linked into planes along (200) by O-H⋯Cl and N-H⋯Cl hydrogen bonds.

Crystal structures of three lead(II) acetate-bridged di-amino-benzene coordination polymers.

Poly[tris-(acetato-κ(2) O,O')(µ2-acetato-κ(3) O,O':O)tetra-kis-(µ3-acetato-κ(4) O,O':O:O')bis-(benzene-1,2-di-amine-κN)tetra-lead(II)], [Pb4(CH3COO)8(C6H8N2)2] n , (I), poly[(acetato-κ(2) O,O')(µ3-acetato-κ(4) O,O':O:O')(4-chloro-benzene-1,2-diamine-κN)lead(II)], [Pb(CH3COO)2(C6H7ClN2)] n , (II), and poly[(κ(2) O,O')(µ3-acetato-κ(4) O,O':O:O')(3,4-di-amino-benzo-nitrile-κN)lead(II)], [Pb(CH3COO)2(C7H7N3)] n , (III), have polymeric structures in which monomeric units are joined by bridging acetate ligands. All of the Pb(II) ions exhibit hemidirected coordination. The repeating unit in (I) is composed of four Pb(II) ions having O6, O6N, O7 and O6N coordination spheres, respectively, where N represents a monodentate benzene-1,2-di-amine ligand and O acetate O atoms. Chains along [010] are joined by bridging acetate ligands to form planes parallel to (10-1). (II) and (III) are isotypic and have one Pb(II) ion in the asymmetric unit that has an O6N coordination sphere. Pb2O2 units result from a symmetry-imposed inversion center. Polymeric chains parallel to [100] exhibit hydrogen bonding between the amine and acetate ligands. In (III), additional hydrogen bonds between cyano groups and non-coordinating amines join the chains by forming R 2 (2)(14) rings.