Synthesis of polyoxometalate based copper-amino-triazole inorganic-organic hybrid materials and related chemistry

We have described in this article a copper(II) compound [Cu(C9H7N4O)2]n (1) and two polyoxometalate (POM)-based inorganic-organic hybrid materials [(C2H6N5)2(C9H9N4O)2][Cu(H2O)2(C9H8N4O)2(PW12O40)2] (2) and [Cu(C9H8N4O)6][HPW12O40] (3). Compound 1 is coordination polymer based on the coordination complex [Cu(C9H7N4O)2], where the ligand C9H7N4O is 4-(salicylideneamino)-1,2,4-triazole (Hsaltrz). Compounds 2 and 3 additionally include the phospho-tungstate type polyoxometalate (POM). Compound 2 is unique in the sense that it is isolated with the 1,4-diamino-4H-1,2,4-triazolium cation [C2H6N5]2+, which is formed in-situ from Hsaltrz during the synthesis of compound 2. Notably, the in-situ formed molecule, 1,4-diamino-4H-1,2,4-triazolium cation, is known to be a high-energy performing molecule. The title compounds have been characterized by routine spectral analysis including their unambiguous characterization by single crystal X-ray crystallography. Density functional theory (DFT) calculations were performed on these three compounds using the Gaussian 09W program to understand the system better.