The direct C–H bond amination represents one of the most straightforward and efficient strategies for C–N bond construction. However, conventional transition metal catalytic systems suffer from critical drawbacks, such as dependence on stoichiometric bases, high reaction temperatures, stringent inert atmosphere requirements, and poor catalyst recyclability. Herein, we report the development of an integrated heterogeneous polyoxoniobate (PONb) catalyst, Cu/FZU-1, achieved via the precise anchoring of catalytically active Cu sites onto an alkaline Nb-oxo cluster. The Cu/FZU-1 exhibited remarkable catalytic performance and recyclability in the direct amination of C–H bonds under mild conditions, achieving excellent yields up to 94% and an outstanding turnover number (TON) of 78. Its remarkable catalytic performance arises from the synergistic interplay of two key components within the integrated catalyst: Nb-oxo polyoxoanions provide Brønsted basicity and anchoring Cu²⁺ ions at the dangling sites serve as active sites for C–H bond activation. This integrated catalyst not only overcomes the bottleneck of low efficiency in the reaction interface, but also provides a new paradigm for precisely identifying active sites at the atomic level in complex catalytic systems.

The introduction of coinage metals (CMs) into lacunary polyoxometalates (POMs) to construct CM-substituted POMs (CM-POMs) has attracted increasing interest over the past decade. This is because CM-POMs combine the unique structural features of POMs and CMs and have promising applications in photocatalysis, luminescence, magnetic materials, etc. In this review, the structural characteristics, synthesis methods, and applications of CM-POMs are summarized in three categories according to the type of their metal core element: Cu-, Ag-, and Au-substituted POMs. Furthermore, this paper discusses the current challenges regarding investigations into the design and properties of CM-POMs.

Polyoxotantalates (POTas) are an important branch of polyoxometalates (POMs) that remain largely undeveloped compared with other members of the POM family including polyoxovanadates, polyoxotungstates, polyoxomolybdates, and polyoxoniobates. Owing to their promising applications in diverse fields such as photo/electrocatalysis, ion conduction, environmental protection, and magnetism, the development of synthetic strategies for new POTas has attracted continuous interest over the past decades. This review summarizes the current status in the development of POTas, including their synthetic methods, crystal structures, physicochemical properties, and potential applications. Additionally, synthetic challenges and prospects are also discussed. It is hoped that this review will be of reference value for the further development of POTas.