Synthesis, Structure And Properties Of Zr-containing Derivatives Based On Keggin-type Polyoxometalates

In this paper, we chose conventional experimental methods and utilize connection of Keggin-type polyoxometalates and transition metal to successfully constructing a novel acetic acid functional of zirconium-containing sandwich-type POM compound. And it was characterized by elemental and thermogravimetric analysis, X-ray crystallography, solution ¹⁸³WNMR, FTIR, and UV spectroscopy, and cyclic voltammetry (CV).1. Compound 1 is a [α-PW₁₀O₃₇]^8–-based organic-inorganic hybrid compound. K₄H₆[Zr₄(OH)₆(CH₃COO)₂(α-PW₁₀O₃₇)₂]·23H₂O (1). Compound 1 is constructed from two dilacunary [α-PW₁₀O₃₇]^8– subunits linked by a Zr₄(OH)₆(CH₃COO)₂ central cluster, leading to a sandwich-type structure. The [α-PW₁₀O₃₇]^8–building block and Zr₄(OH)₆(CH₃COO)₂ tetranuclear cyclic cluster are rare in POM chemistry.2. All the studies, thermogravimetric analysis, X-ray crystallography, solution 183WNMR, FTIR, and UV spectroscopy, indicate that compound 1 is stable both in the solid state and in solution. The bond valence sum (BVS) values of 1 indicate that all these bridged oxygen atoms are monoprotonated, suggesting that compound 1 may has catalytic applications.3. The cyclic voltammograms indicate good electrocatalytic activity in the reduction of nitrite. On addition of NO^2–, all the reduction peak currents increase, and the corresponding oxidation peak currents decrease dramatically, which indicates that both of the reduced species show electrocatalytic activities toward the reduction of nitrite.For compound 1, the loose synthetic restriction, stabilization in solution, and large numbers of protonated bridged oxygen atoms are advantages for prospective catalytic applications. Therefore, In our next study, we will try to explore the catalytic applications of these complexes.