Sandwich-like frameworks encapsulating 1D T5(1) water tapes and discrete octameric water clusters with boat-shaped hexamer

Two sandwich-like frameworks with Ag(I) and mixed flexible ligands, {[Ag2(H2O)2(bpp)2](oba)·4H2O}n (1) and {[Ag2(bpp)2](heda)·8H2O}n (2) (bpp = 1,3-bis(4-pyridyl)propane, H2oba = 4, 4′-oxybis(benzoic acid), H2heda = trans-3-hexenedioic acid), have been synthesized and characterized. In 1, the bpp ligands bridge the Ag(I) ions into 1D sinusoidal chains of [Ag(bpp)]nn+, which are further linked into the cation layer of [Ag2(H2O)2(bpp)2]n2n+ by Ag⋯π and Ag⋯Ag interactions. The noncoordinated oba2 − serves as template driving surrounding water molecules to aggregate into the anionic layer of [(oba)·4H2O]n2n−. In 2, the similar [Ag2(bpp)2]n2n+ cationic layer is based on Ag⋯π interactions. The heda2 − and surrounding water molecules construct another 2D layer of [(heda)·8H2O]n2n−. Hydrogen bonds make the cationic and anionic layers into sandwich-like frameworks. Interestingly, 1D T5(1) water tapes with cyclic vertex-sharing pentamer cluster units and discrete water octamers with a boat-shaped hexamer were observed in 1 and 2, respectively. The novel water tape and discrete water octamer with a boat-shaped hexamer are different from water clusters described in previous reports. The luminescent behaviors and thermogravimetric analysis of 1 and 2 have been also discussed.