The clash of the synthons: crystal structures of benzimidazole–alcohol–carboxylic acids

Abstract

The crystal structures of a series of compounds containing protonated benzimidazole functions are reported. Hydrogen bonds are always seen in the plane of the benzimidazole but, in opposition to our previous work, stacking interactions between the benzimidazole cations are not invariably observed. In zwitterionic benzimidazole carboxylic acid compounds, a gauche conformation is often adopted which allows a Coulombic attraction between carboxylate and benzimidazolonium functions.

Molecular bricklaying II. : Anion and chain length effects in bisbenzimidazolonium salts

“…4a) and the tapes stack on top of each other to form sheets so that the N atoms of the cyanide ligands lie above the C2 atoms of the benzimidazoles and at a distance of 3.20 A ˚(Fig 4b). This is the favoured position for anion binding to the benzimidazoles as we showed in a previous paper, 34 and is also seen in the salt of 8. Neighbouring sheets in the crystal are related by a twofold screw axis which allows the projecting phenyl groups of one sheet to fit into the gaps between phenyls of the next sheet.…”

Coordination Chemistry of the Chiral, Facially Coordinating Tridentate Ligand 1,2‐Bis(benzimidazol‐2‐yl)ethanol with 3d Transition Metals

“…The non‐coordinated benzimidazole of ligand 4 is protonated, and shows a stacking interaction with a coordinated benzimidazole of the complex generated by the twofold screw axis along a . We have previously established the strong tendency of benzimidazole cations to give stacking interactions[16b], but this is the first time we have observed a stack between a protonated and a coordinated benzimidazole. The chains along the a ‐axis are linked by hydrogen bonding along the c ‐axis.…”

“…The crystal packing of the divalent complexes is dominated by two factors: hydrogen bonding between the alcohol hydrogens and the counterions and π–π stacking between the coordinated benzimidazoles. This latter interaction generally requires the electron rich phenyl moiety to overlap, as far as possible, with the electron poor imidazole unit . The structure of the complexes confers on the trans complexes the form of a capital X if looking along the O–M–O axis, the arms being formed by the benzimidazoles.…”

Assembly of ZnIIand CdIIcoordination polymers with different dimensionalities based on the semi-flexible 3-(1H-benzimidazol-2-yl)propanoic acid ligand

“…3-(1H-Benzimidazol-2-yl)propanoic acid (H 2 BIP) was prepared by a literature method (Delval et al, 2008). Other reagents and solvents used in the reactions were purchased from Aladdin-Chemical and used without purification.…”