Ring-Shaped Rhenium(I) Multinuclear Complexes: Improved Synthesis and Photoinduced Multielectron Accumulation

We successfully developed selective synthesis of strongly emissive ring-shaped Re­(I) multinuclear complexes (RnP­(x) n+ in Chart ) with much higher yields compared with the previously reported method. This improved method could also be employed to prepare a novel ring-shaped multinuclear complex composed of structurally different Re­(I) units. Each Re unit in RnP­(x) n+ could electrochemically accept one electron, and the multielectron reduced states of RnP­(x) n+ were stable. In the presence of triethanolamine, the ring-shaped tetranuclear and hexanuclear complexes can be photochemically reduced and accumulate 2.9–3.6 and 4.4 electrons in one molecule, respectively.