Recent advances in lanthanide-coordinated polyoxometalates: from structural overview to functional materials

• Summary of the peculiar properties of lanthanide-coordinated polyoxometalates. • Review of the main application fields of LnPOM-based materials. • Recent advances in the design and fabrication of LnPOM-based materials. • Future trends of the emerging roles of LnPOM-based functional devices. Lanthanopolyoxometalates (LnPOMs), obtained through the coordination of polyoxometalates (POMs) and lanthanide ions (Ln), have received extraordinary interest of the scientific community over the last decades. The synergistic combination between the peculiar properties of Ln cations and POMs results in coordination compounds with notable and enhanced physico-chemical features. A plethora of different LnPOM architectures have been reported to date using vacant POM structures (Keggin, Lindqvist, Wells-Dawson, Preyssler-type, and others) as building blocks, and are briefly reviewed in this chapter. The remarkable features of LnPOMs have led to a significant effort in the design of novel LnPOM-based materials for applications in a wide range of technological areas, being prepared via immobilization, intercalation or encapsulation approaches using a variety of support systems. The main synthetic routes for the preparation of LnPOM-based materials, namely the use of nanoparticles, surfactants, mesoporous (organo)silica, metal–organic frameworks, thin films, and others are also here revisited. Several functional materials and devices have been recently developed taking advantage of the unique LnPOMs properties for applications in heterogeneous catalysis, medical imaging, magnetism, chromism, optical and chemical sensing. In this chapter, a comprehensive review of the recent advances in the design and fabrication of LnPOM-based materials according to its specific area of application is provided.