Anion-directed assembly of three cationic silver(I) coordination polymers with bis(imidazolyl)-based linker: Structural characterization and anion exchange study

Three cationic silver(I) coordination polymers, namely [Ag2(μ-bib)3](SO3CF3)2·(CH3CN)n (1), [Ag(μ-bib)](NO3)·(H2O)n (2), and [Ag(μ-bib)]BF4n (3), have been prepared using flexible bis(imidazolyl)butane (bib) ligand and silver salts of different anions. All compounds are characterized by FT-IR, PXRD, elemental analysis, and single-crystal X-ray diffraction. Compound 1, containing triflate (SO3CF3−) anions, exhibits a two dimensional 63-hcb network with an amazing ABCDEF packing mode of the single hexagonal layers. Compound 2, containing nitrate ions, forms a simple one dimensional wavy chain, while compound 3 with BF4− anions, shows a double helix DNA-shaped structure stabilized by Ag⋯Ag interactions between the two strands. The anions in the structures 1–3 are non-coordinating and participate in weak H-bonding, while imidazolyl rings are involved in π⋯π stacking interactions. Anion exchange experiments in aqueous solution, monitored by FT-IR and PXRD analyses, reveal interesting structural transformations.