Electroactive chain-like compounds constructed from trimetallic clusters and 4,4′-bipyridine spacers: One-pot synthesis, characterization and surface binding

This paper reports the synthesis and characterization of a novel series of chain-like compounds where oxo-centered triruthenium cluster moieties are bridged by 4,4′-bipyridine (4,4′-bpy) spacers. A reaction of solvent-coordinated triruthenium "monomer" precursor [Ru ₃O(CH₃CO₂)₆(CO)(CH ₃OH)₂] with a 0.1 equimolar amount of 4,4′-bpy in CH₃OH gave mixture of chain-like compounds containing "dimers" to "tetramers" which were cleanly separated by column chromatography and characterized by spectroscopic and electrochemical methods. Cyclic voltammetry revealed that all chain-like compounds exhibit reversible and stepwise redox processes in solution with very weak intramolecular coupling between the triruthenium components across the 4,4′-bpy bridge. Photo-induced dissociation of CO from the compounds and electrode surface binding were also investigated.