Synthesis, structure and fluorescence of a 2-D network tetra-ZnII-substituted sandwich-type Keggin tungstoarsenate: {[Zn(dap)2(H2O)]2[Zn(dap)2]2[Zn4(Hdap)2(B-α-AsW9O34)2]}⋠4H2O

A new 2-D network tetra-ZnII-substituted sandwich-type Keggin tungstoarsenate {[Zn(dap)2(H2O)]2[Zn(dap)2]2[Zn4(Hdap)2(B-α-AsW9O34)2]}·4H2O (1) (dap = 1,2-diaminopropane) has been synthesized by combining the conventional aqueous solution method and the hydrothermal method and structurally characterized by elemental analyses, X-ray powder diffraction (XRPD), IR spectrum, thermogravimetric analysis (TGA) and single-crystal X-ray diffraction. Structural analysis shows that 1 displays an interesting 2-D (4,4)-topological network constructed by tetra-ZnII-substituted sandwich-type Keggin tungstoarsenate units and [Zn(dap)2)2+] linkers. To our knowledge, 1 represents the first 2-D network Zn-substituted sandwich-type tungstoarsenate. The fluorescent properties of 1 have also been investigated.