Hydrothermal synthesis and structural characterization of a new inorganic-organic hybrid compound with photocatalytic activity based on Keggin-type polyanion and cadmium-1, 2, 4-triazolate units

A new inorganic-organic hybrid compound constructed from Keggin-type polyoxometalate and cadmium-organic units, namely, [Cd(Htrz)(3)](2)[SiW12O40]center dot 2H(2)O (1), [Htrz = 1-H-1,2,4-triazole], has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction, IR, TG, and UV-vis absorption spectra. In compound 1, each [SiW12O40](4-) cluster is modified by six [Cd(Htrz)(3)](2+) metal-organic fragments, meanwhile, each [Cd(Htrz)(3)](2+) also connects with three [SiW12O40](4-) to built up a binodal (3,6)- connected 2D planar network with the (4(3))(2)(4(6).6(6).8(3))-kgd topology. Interestingly, [SiW12O40](4-) cluster exhibits a rare coordination mode acting as a hexadentate ligand, in which all of the six terminal oxygen atoms in the equatorial plane are synchronously participated in coordination. The diffuse reflectivity spectrum shows it can be regarded as a wide gap semiconductor. Moreover, the photocatalytic performance shows good photocatalytic activity for the degradation of Rhodamine B. (C) 2012'Elsevier B.V. All rights reserved.