Synthesis and catalytic activities of two new extended Preyssler-type tungstophosphates with different cavity centers

Two new extended Preyssler-type polyoxometalates with different cavity centers constructed by Fe(III), 2,2′-biimidazole and Preyssler-type tungstophosphate anions display higher catalytic performances toward the synthesis of cyclohexanone ethylene ketal and can be reused.