Constructing multiple active Cu(II) sites via intramolecular N/O competitive coordination for efficient hydroboration of terminal alkynes

Copper-based catalysts for hydroboration typically rely on air-sensitive Cu(I) species to achieve high activity, whereas Cu(II)-only systems remain largely ineffective due to their limited intrinsic reactivity. Herein, we present an intramolecular N/O competitive coordination strategy to construct a metal–organic framework (MOF) with multiple active Cu(II) sites (Cu-3,5-PyDC). This framework incorporates three distinct Cu(II) coordination environments: [Cu 2 -O 8 ], [Cu-N 2 O 2 ], and [Cu-N 3 ], which regulate the local electronic microenvironment of Cu(II) and significantly enhance its catalytic functionality. Consequently, Cu-3,5-PyDC is capable of completing the hydroboration of 25 terminal alkyne substrates within 5 min, achieving a turnover frequency up to 3046 h −1 . Combining deuterium experiments with density functional theory (DFT) calculations further reveals the synergistic interaction of multiple Cu(II) sites in the proton-hydrogen transfer pathway, which effectively lowers the reaction energy barrier. This work establishes the effectiveness of intramolecular N/O competitive coordination strategies for precisely constructing multiple active sites within MOFs, providing a rational design approach for the targeted development of multifunctional materials.