Three 3D silver-bis(triazole) metal-organic frameworks stabilized by high-connected Wells-Dawson polyoxometallates

Three silver-bis(triazole) three-dimensional (3D) metal-organic frameworks (MOFs) with Wells-Dawson type polyoxometalates (POMs) as high-connected inorganic ligands have been isolated: [Ag7(bte)4(H2O)(HP2W(VI)16W(V)2O62)]·2H2O (1), [Ag7(btp)5(HP2W(VI)16W(V)2O62)]·H2O (2) and [Ag4(btb)3.5(P2W18O62)](H2btb)·2H2O (3) (bte = 1,2-bis(1,2,4-triazol-1-yl)ethane, btp = 1,3-bis(1,2,4-triazol-1-y1)propane, btb = 1,4-bis(1,2,4-triazol-1-y1)butane). Compound 1 contains a 3D metal-organic subunit, which is constructed from 1D Ag/bte chains and 2D layers based on hexanuclear [Ag6(bte)2](6+) circuits. The [P2W18O62](8-) (P2W18) anions act as 10-dentate inorganic ligands incorporated into the channels of the 3D framework. In compound 2, the metal-organic subunits are a 2D layer constructed from the [Ag5(btp)2](5+) circuits and flexible Ag/btp helical chains. The P2W18 anions also act as 10-dentate inorganic ligands linking adjacent 2D layers to construct a 3D framework. Both 1 and 2 contain Ag-Ag bonds, which further stabilize the structures. Compared with 1 and 2, the metal-organic subunit of 3 is a 3D cage-like host architecture. Without the assistance of Ag-Ag bonds, two sets of these 3D MOFs interpenetrate each other to generate a 2-fold interpenetrating structure for stability, which are united by the 5-dentate P2W18 anions to construct an integrated 3D structure. The roles of coordination modes of silver centers and POMs, as well as the effects of organic ligand lengths on the metal-organic subunit and final structures, have been reported. In addition, the electrochemical properties, photochemical catalysis and antibacterial properties of title compounds have also been investigated.