Repairable photoactive polymer systems via metal-terpyridine-based self-assembly

The development of sustainable polymeric photo-catalytic systems for the conversion of solar energy is an important issue. In this perspective, efficient photo-catalytic systems have been developed by many research groups; however, their long-term stability or sustainability is still challenging and need to be resolved. In order to realize sustainable polymeric photoactive systems, we developed terpyridine (tpy)based polymers and their ruthenium complexes, which were reversibly assembled and disassembled through metal ion-ligand interactions. In the presence of metal ions, Ru-based photoactive polymers were assembled on tpy-coated ITO substrates, generating visible-light induced photocurrents. Subsequently, when disassembled by the introduction of tetra-n-butylammonium fluoride, the assembled polymeric complex decomposed, decreasing the photocurrent. However, the photocurrent efficiency of this system was recovered through re-assembly and repeated several times without a significant decrease in its efficiency. In addition, a sustainable photo-catalyst system was achieved by photo-oxidative coupling with benzylamine. The initial active photo-catalytic system became inactive after disassembly; however, its activity was restored through assembly again, and this process was repeated successfully several times. The self-assembly via reversible metal ion-ligand interaction would enable photo-catalytic systems to be self-repairable and sustainable.