Ligand‐Directed Approach in Polyoxometalate Synthesis: Formation of a New Divacant Lacunary Polyoxomolybdate [γ‐PMo₁₀O₃₆]⁷⁻

Abstract

Polyoxometalates (POMs) have received increasing attention over the last decades for extending their application and properties that originate from novel structures. For the synthesis of a variety of POM structures, multivacant lacunary POMs are key precursors, which are typically synthesized by empirically controlling the complex equilibrium in aqueous solvents. Unfortunately, despite the excellent catalytic and electrochemical properties of “polyoxomolybdates”, only one multivacant lacunary species, i.e., [A‐α‐PMo9O34]9−, has been identified and isolated because multivacant lacunary polyoxomolybdates are typically unstable. Here we report a ligand‐directed approach for the selective formation of an unprecedented lacunary polyoxomolybdate in organic solvents. By structure transformation of a pyridine‐coordinated [A‐α‐PMo9O34]9−, a new γ‐Keggin‐type divacant lacunary polyoxomolybdate [γ‐PMo10O36]7− was obtained, which can be further used as a precursor for synthesizing a POM–organic hybrid.

Study on the incorporation of various elements into the Keggin lacunary-type phosphomolybdate [PMo9O34]9− and subsequent purification of the polyoxometalates by nanofiltration

“…This is mainly due to the fact that phosphomolybdates are less stable than the corresponding tungstates. There are some reports of the lacunary phosphomolybdate structures dating back as far as the 1970s, [33][34][35][36][37][38] however a detailed study of this compound is still missing.…”