Copper-site-engineered integrated polyoxoniobate catalyst for efficient heterogeneous C–H bond amination

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.