Synthesis of a new bis(ferrocenyl)ruthenacyclopentatriene compound with a significant inter-metal electronic communication

A new 2,5-bis(ferrocenyl)ruthenacyclopentatriene complex was synthesized by the metallacycle formation reaction of RuBrCp(cod) (Cp=η5-C5H5) and ethynylferrocene. Cyclic voltammetry of the complex showed a reversible one-electron reduction due to the ruthenacycle and a two-step one-electron oxidation of the ferrocenyl moieties. Separation of the redox potentials of the ferrocenyl moieties was 0.24 V, and the electronic spectrum of one-electron oxidized species exhibited an intervalence-transfer band at 1180 nm. These results indicate the existence of significant electronic interactions between two ferrocenyl moieties through the ruthenacyclopentatriene ring.