Preyssler-type polyoxometalates, smallest POM with internal cavity: Synthesis, structure and function

Polyoxometalates (POM) are metal oxide clusters. There are many classical POM types, such as Lindqvist type, Weakley-type, Strandberg-type, Anderson type, Evans - Showell-type, Keggin type, Wells–Dawson type, etc. Recently, Preyssler-type (PT) POM has caught serious attention due to (a) high thermal stability, (b) having flexible binding mode at different condition, i.e. {NaP5W30O110} can coordinate internally and externally, (c) presence of 30 surface oxygen as external binding sites, (d) stability in long pH range (1–10), (e) Preyssler POM can be a good acid as well as redox catalyst, (f) unique structural symmetry of the ligand field, low computational cost (a combination of molecular symmetry and medium size). Moreover, PT POMs are also smallest POM with internal cavity. This review highlights the unique structure and property of PT POM based materials.