Conformational differences and intermolecular C-H...N interactions in three polymorphs of a bis(pyridinyl)-substituted benzimidazole

Inter-molecular inter-actions in a phenol-substituted benzimidazole

Hydrogen bonding plays an important role in the design of solid-state structures and gels with desirable properties. 1-(4-Hydroxybenzyl)-2-(4-hydroxyphenyl)-5,6-dimethyl-1H-benzimidazole was isolated as the acetone disolvate, C22H20N2O2·2C3H6O. O-H⋯N hydrogen bonding between benz-imidazole mol-ecules results in chains parallel to [010]. One of the acetone solvate mol-ecules participates in O-H⋯O hydrogen bonding with the benzimidazole derivative. C-H⋯π inter-actions are observed in the extended structure. Hirshfeld surface analysis was used to explore the inter-molecular inter-actions and density functional theory was used to estimate the strength of the hydrogen bonds.

Structural characterization of two solvates of a luminescent copper(II) bis-(pyridine)-substituted benzimidazole complex

Copper(II) complexes of benzimidazole are known to exhibit biological activity that makes them of inter-est for chemotherapeutic and other pharmaceutical uses. The complex bis-(acetato-κO){5,6-dimethyl-2-(pyridin-2-yl)-1-[(pyridin-2-yl)meth-yl]-1H-benzimidazole-κ2N2,N3}copper(II), has been prepared. The absorption spectrum has features attributed to intra-ligand and ligand-field transitions and the complex exhibits ligand-centered room-temperature luminescence in solution. The aceto-nitrile monosolvate, [Cu(C2H3O2)2(C20H18N4)]·C2H3N (1), and the ethanol hemisolvate, [Cu(C2H3O2)2(C20H18N4)]·0.5C2H6O (2), have been structurally characterized. Compound 2 has two copper(II) complexes in the asymmetric unit. In both 1 and 2, distorted square-planar N2O2 coordination geometries are observed and the Cu-N(Im) bond distance is slightly shorter than the Cu-N(py) bond distance. Inter-molecular π-π inter-actions are found in 1 and 2. A weak C-H⋯π inter-action is observed in 1.

A luminescent bis(pyridyl)-substituted benzimidazole platinum(II) complex exhibiting an intermolecular anagostic interaction

The photophysical properties of transition metal complexes of the 5,6-dimethyl-2-(pyridin-2-yl)-1-(pyridin-2-ylmethyl)-1H-benzimidazole ligand are of interest. Dichlorido[5,6-dimethyl-2-(pyridin-2-yl)-1-(pyridin-2-ylmethyl)-1H-benzimidazole-κ2 N 2,N 3]platinum(II), [PtCl2(C20H18N4)], is luminescent in the solid state at room temperature. The compound displays a distorted square-planar coordination geometry. The Pt—N(imidazole) bond length is shorter than the Pt—N(pyridine) bond length. The extended structure reveals that symmetry-related molecules display weak C—H...N, C—H...Cl, and C—H...Pt hydrogen-bonding interactions that are clearly discernable in the Hirshfeld surface and fingerprint plots. The intermolecular C—H...Pt and C—H...N interactions have been explored using density functional theory. The result of an analysis of the distance dependence of C—H...Pt yields a value consistent with that observed in the solid-state structure. The energy of interaction for the C—H...Pt interaction is found to be about −11 kJ mol−1.

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.