The Heteroleptic Cu(I) Photosensitizer‐Containing 3,8‐Disubstituted Phenanthroline: Synthesis, Photophysical Properties and Photocatalytic Hydrogen Evolution from Water.

Four novel heteroleptic Cu(I) photosensitizers with 3,8‐diaryl‐2,9‐diisopropyl‐1,10‐phenanthroline derivatives as electron‐donating bidentate N‐ligands have been designed and synthesized. The metal copper complexes are studied in light‐driven water reduction system. And the substituent effect at the 3,8‐positions of N‐ligands impacting on photosensitive activity and photoelectric chemical properties are explored and discussed. Surprisingly, with the enhancement of electron‐donating capacity of substituent group at 3,8‐sites of 1,10‐phenanthroline, the photosensitive activity of photosensitizer linearly increases, and photocatalytic performance up to 817 turnover numbers (TON) was reached combining with water reduction catalyst (WRC), Fe3(CO)12. The photocatalytic performance of these photosensitizers dramatically increased compared to 2,9‐diispropyl‐1,10‐phenanthroline complex (TON = 89). Moreover, the introduction of methoxy substituent to copper complexes, which could increase the fluorescence lifetimes (τmax = 209 ns) and promote hydrogen evolution. [ABSTRACT FROM AUTHOR]