Various Silver Phosphinate Inorganic Architectures in Three-Dimensional Frameworks with Argentophilic Interactions

Abstract

Three silver compounds with the formulas: [Ag2(HL1)] (1), [Ag10(L2)2(H2O)1.25] (2), and [Ag5(L3)]·1.5H2O (3) were obtained by self-assembly of silver nitrate with 4,4′-phosphinicobis-dibenzoic acid (H3L1), 4,4′-phosphinicobis-diisophthalic acid (H5L2), and 2,2′-phosphinicobis-diisophthalic acid (H5L3) under hydrothermal conditions. The structures of these compounds were confirmed by various characterization methods. Both 1 and 2 crystallize in P21/n space group and present three-dimensional (3D) frameworks, which contain a sliver phosphinate inorganic chain or sheet formed by Ag–Ag interactions. Meanwhile, compound 3 is in C2/c space group and also displays a 3D silver-organic architecture. The open-framework contains narrow channels along the c-axis with an opening of 0.26 nm × 0.32 nm. The intriguing feature of the structure is emergence of a 3D inorganic skeleton in 3, which struts the whole framework. The 3D inorganic skeleton is generated from a silver phosphinite chain connected by strong Ag–Ag interactions. At room temperature, the compounds exhibit blue photoluminescence.