The first 3D host–guest structure based on a three-fold interpenetrated Ag-pz coordination polymer network and Keggin-type aluminum tungstates with photo/electro-catalytic properties

Abstract

A new 3D POM-based coordination polymer network, [{Ag₅(pz)₇}{AlW₁₂O₄₀}]·4H₂O (1) (pz = pyrazine), has been synthesized under hydrothermal conditions and characterized by elemental analysis, IR, UV-vis, XRD, TG, and single-crystal X-ray diffraction. In compound 1, 3-coordinated Ag3 and 4-coordinated Ag2 are alternately joined together to form a large decagon ring by sharing pz or “V”-like Ag4-pz bridges. Each large ring is connected with six adjacent rings via the edge-sharing modes resulting in an infinite 2-D layer. It is worth noting that the “Y”-shaped Ag1-pz segment is suspended on the ring through sharing pz with the Ag2-pz tetrahedron, which is an important linkage unit extending the 2-D layers to a three-fold interpenetrating Ag-pz network with (10³·12³) (10³)(10)₂(12²·14) topology. The Keggin {AlW₁₂} as inorganic ‘guest’ units are encapsulated into the channel of the Ag-pz framework to form a complex POMOF 3D network. In addition, compound 1 exhibits better electrocatalytic properties to reduce hydrogen peroxide and good photocatalytic activity for the degradation of rhodamine B (RhB), methyl orange (MO), methylene blue (MB) and azophloxine (AP).