Grafting of Secondary Diolamides onto [P₂W₁₅V₃O₆₂]⁹⁻ Generates Hybrid Heteropoly Acids

Abstract

The Dawson tungstovanadate [P2 W15 V3 O62 ](9-) can be grafted to secondary diolamides. The electron-withdrawing character of the polyanion increases the acidity of the amide proton, leading to an organo-polyoxometalate, which can be used as a Brønsted organocatalyst. High-field NMR and DFT modeling indicate that the amide proton stays on the nitrogen and that the exalted acidity derives from the interaction between the organic and inorganic parts of the organo-polyoxometalate. The amide-inserted vanadotungstates thus form a new family of (hybrid) heteropolyacids, offering new perspectives for the application of POM-based catalysis in organic synthesis.