Synthesis and Structural Characterization of Multi‐Molybdenum‐Substituted Preyssler‐type Phosphotungstates

We report the synthesis of multi‐Mo‐substituted Preyssler‐type phosphotungstates, [P5W30‐xMoxO110Na(H2O)]14−, with different amounts of incorporated Mo via the hydrothermal reactions of H3PO4, Na2WO4, and Na2MoO4; and characterization by 31P nuclear magnetic resonance (NMR), Fourier‐transform infrared (FT‐IR), elemental analysis, electrospray ionization‐mass spectrometry (ESI‐MS), and cyclic voltammetry. The number of substituted Mo increases by increasing the amount of Na2MoO4 in the reaction mixture, and in the [P5W30‐xMoxO110Na(H2O)]14−, up to penta‐Mo‐substituted species can be produced as mixtures of isomers with different Mo numbers and Mo positions. Single crystal X‐ray structure analysis and density functional theory calculation indicate that the most suitable substitution position is the belt position. The reaction of Na2WO4 and Na2MoO4 with H3PO4 produces multi‐Mo‐substituted Preyssler‐type phosphotungstate, [P5W30‐xMoxO110Na(H2O)]14− (x up to 5).