Synthesis of an electron pooling ligand based on triruthenium clusters and electrochemical reduction of CO₂ by its zinc(II) complex

An electron pooling complexed ligand (PL) was prepared by linking μ₃-oxo Ru₃ clusters with 1,4,7-tris(4-pyridylmethyl)-1, 4,7-triazacyclononane (pic₃tacn). The cyclic voltammogram of the pooling ligand appeared similar to the Ru₃ cluster monomers. Each wave corresponded to three simultaneous 1e^- processes. In the presence of Zn(II) ions, CO₂ was reduced, indicating cooperation between the Ru₃ cluster centers. IR spectroelectrochemistry (IRSEC) indicated that the products of reduction were carbonate and formate and CO.