A discrete water hexamer with a new planar tetrameric water moiety trapped in the crystal host of [Ag(azelate)(4,4′-bipyridine)]·(H2O)3

The ultrasonic reaction of Ag2O, bipy and H2aze gave rise to a novel Ag(I) mixed-ligand coordination polymer, namely [Ag(aze)(bipy)]·(H2O)3 (1) (bipy = 4,4′-bipyridine, H2aze = azelaic acid). In 1, Ag(I) ions are linked by bipy and aze ligands to form a single two-dimensional (2D) undulated net with a (6,3) topology, incorporating Ag6(bipy)4(aze)2 windows of 22.58 × 11.06 Å based on Ag⋯Ag distances. A pair of identical 2D single nets are interconnected via π⋯π stacking and unsupported Ag⋯Ag interactions to generate a 2D double-layered net. A discrete water hexamer composed of a new planar tetrameric water ring and two pendent water molecules is perpendicularly located in each hydrophilic cavity of the 2D bilayer and acts as a ‘glue’ to assemble adjacent 2D double-layered nets into a three-dimensional (3D) structure.

► The first silver(I) coordination polymer containing azelate ligand was synthesized and structurally characterized.
► The 2D double-layered net is observed in the coordination polymer.
► A discrete water hexamer is perpendicularly located in each hydrophilic cavity of the 2D bilayer.
► Thermal and IR behaviors of the coordination polymer were also discussed.