Synthesis, characterization, and electrochemical behavior of mono- and bimetallic ruthenium and rhenium allenylidenes bearing multiconjugated organic spacers

Novel monoallenylidenes of Ru and Re and homobimetallic Ru/Ru and heterobimetallic Ru/Re complexes bridged by multiconjugated aromatic organic spacers such as bianthra-cenylidene and biphenylene were obtained and characterized by conventional spectroscopic techniques and elemental analysis. Electrochemical measurements coupled to spectroelectrochemistry and EPR spectroscopy proved that in the bis(allenylidene) complexes an electronic communication is present between either the two allenylidene bridges or the two metal centers, enticing extended intramolecular electronic mobility.