Photoinduced Self‐assembly: An Alternative Strategy for the Construction of Coordination Oligomers and Polymers

Abstract

Self‐assembled oligonuclear and polynuclear complexes have numerous functionalities and potential applications. Generally, such compounds have been constructed by thermal substitution reactions with bridging ligands. Herein, we report bottom‐up and photochemical construction of functional coordination oligomers and polymers by photosubstitution‐induced self‐assembly. The photosubstitution reactions of a ruthenium precursor complex with bridging ligands having pyrazole moieties afford mono‐, di‐, tri‐, tetra‐, and pentanuclear ruthenium complexes, Ru1–Ru5, which have one‐dimensional architectures. Intramolecular hydrogen bonding between each bridging ligand is a key to construct the molecular nanowires. All the complexes have been isolated and thoroughly characterized. The photochemically synthesized ruthenium complexes act as synthons for longer metal‐complex‐based nanowires with a length of the order of tens‐of nanometers. The multinuclear complexes are generated by photoinduced self‐assembly in the presence of a base, and they undergo photoinduced disassembly in the presence of acid.