Through-Space Charge Transfer Complexes Based on Terpyridine Bi-Functionalization for Efficient Solar-Driven H₂O₂...

To achieve precise spatial control of donor-acceptor (D-A) stacking and optimize through-space charge transfer (TSCT) for efficient photocatalysis, we develop a novel terpyridine bi-functionalization strategy, which utilizes the dissymmetrical 6- and 4'-functionalization of 2,2':6',2″-terpyridine (tpy) scaffold with triphenyltriazine (acceptor) and triphenylamine (donor) units. Using this strategy, we designed and synthesized two ligands, L1 and L2, differing by a single phenylene unit in length. Upon coordination with Zn(II), the D and A units in the resulting complexes S1 and S2 are precisely edited at the molecular level, giving rise to distinct stacking geometries: slip-stacked S1 and co-facially S2. S2 significantly enhances TSCT, resulting in improved visible-light absorption, prolonged charge carrier lifetime, superior charge separation efficiency and achieves a photocatalytic efficiency (2063 µmol g^-1 h^-1) for H₂O₂ production that is twice that of S1 without the need for sacrificial agents. This work demonstrates the unique advantages of terpyridine bi-functionalization strategy in constructing photocatalytic materials with tunable TSCT, providing new insights for the design and functional development of supramolecular systems.