Unusual hexamers and infinite water chains trapped in the complexes of 2-(4-pyridyl)benzimidazole

Unusual hexamers and water chains have been observed in the complexes of (HPyBIm)+(Hterephate)−(PyBIm) · 4H2O (1) and [Ag2(PyBIm)2(μ2-SO4)] · 4H2O (2), respectively (PyBIm = 2-(4-pyridyl)benzimidazole). In 1, a chair-shaped hexamer (not water hexamer) formed by the water molecules and carboxylate groups as well as one-dimensional water chain are being observed. While in 2, a water hexamer-shaped as parallelogram is obtained; more interestingly, the parallelogram-shaped water hexamers are further aggregated into tape like infinite water chain via hydrogen-bonding interactions.

Graphical abstractTwo unusual hexamers trapped in the complexes of 2-(4-pyridyl)benzimidazole are being observed. A chair-shaped hexamer (not water hexamer) formed by the water molecules and carboxylate groups is found in complex 1. While in 2, a parallelogrammic configuration based on six water molecules is obtained; which is further aggregated into one-dimensional water chain via hydrogen-bonding interactions. The structural parameters imply the functional groups of the organic ligands play important roles in stabilizing water clusters with different size and shapes.Figure optionsDownload full-size imageDownload as PowerPoint slide