A Triphenylamine‐Integrated Cu(I) Cyclic Trinuclear Complex for Solar‐Driven Cross‐Dehydrogenative Coupling

Comprehensive Summary Meeting the growing demand for clean and sustainable energy requires the development of efficient light‐driven catalytic technologies capable of converting solar energy into chemical value. Photocatalysis represents a particularly attractive strategy. However, the rational design of photocatalysts that combine cost‐effectiveness, long‐term stability, and high activity remains a major challenge. Many existing systems suffer from limited visible‐light absorption or inefficient separation of photoinduced charges, which restricts their practical applicability. In this work, we reported an integrated catalytic system (complex 1 ) in which a novel triphenylamine (TPA) group was introduced into a copper‐based cyclic trinuclear complex (CTC). The introduction of the strong electron‐donating TPA unit markedly enhanced visible‐light absorption and promoted efficient charge separation within this collaborative system. These features lead to a stable photocurrent response and reduced electrochemical impedance, indicating improved charge transport and suppressed recombination. As a heterogeneous photocatalyst, complex 1 exhibits exceptional performance in cross‐dehydrogenative coupling (CDC) amination reactions between the phenol derivatives and phenothiazine derivatives. These reactions proceeded under mild reaction conditions, using natural light irradiation without the need for strong base and high temperature. The catalyst 1 showed broad applicability, delivering consistently high yields (up to 97%) across more than twenty different substrates. In addition to its high activity, complex 1 exhibits good recyclability and durability, retaining its catalytic activity and structural integrity over at least five cycles. Mechanistic investigations reveal that, under light irradiation, complex 1 efficiently generates superoxide radical anion. These reactive species play a crucial role in activating the reactants to form key radical intermediates, which subsequently couple to afford the desired amination products. Overall, this work demonstrates that integrating a photoactive organic unit into a copper‐based framework is an effective strategy for creating durable and efficient photocatalysts, highlighting the promise of TPA‐modified copper complexes for sustainable, solar‐driven organic transformations.