Construction of Heterovalent Cu(I)/Cu(II) Dual-Site Catalysts via Terpyridine Ligands: Topological Modulation and Synergistic Catalysis.

Dual-site heterogeneous catalysts hold great promise for the efficient conversion of substances. However, challenges remain in the precise construction of dual-site heterovalent structures and the realization of efficient cocatalysis. This study reports the construction of dinuclear heterovalent metal catalysts via pyridine-based ligands and cuprous iodide clusters, and the investigation of their catalytic activities in the oxidative coupling of benzylamine. By adjusting the ligand geometry, structural tuning from one-dimensional (1D) chains to two-dimensional (2D) cyclic frameworks was achieved to obtain a series of dinuclear heterovalent metal catalysts (DCu-T1 to DCu-T6). Among them, the cyclic DCu-T6 exhibited superior catalytic performance in benzylamine coupling, with a conversion rate of 99%, which significantly surpassed that of the mononuclear control catalyst TPY-Cu (20%). Mechanism studies reveal a synergistic effect between binuclear metal sites of different valence states, which is validated by electron paramagnetic resonance (EPR), in situ infrared (IR) spectroscopy, and theoretical calculations. These results provide a strategy for the construction of high-performance dual-site heterovalent catalysts and clarify the atomic-level catalytic mechanism responsible for their enhanced efficiency.