Ruthenium cluster compounds containing 1,1′-bis(diphenylphosphino)ferrocene (dppf):: an electrochemical analysis and the crystal structure of [Ru3(CO)11]2(μ-dppf)

The electrochemistry of 1,1'-bis(diphenylphosphino)ferrocene (dppt) derivatives of Ru-3(CO)(12) was investigated. Two known compounds [Ru-3(CO)(8)(rho-dppf)(2) (1) and Ru-3(CO)(10)dppf (2)] and a new compound [Ru-3(CO)(11)(mu-dppf)Ru-3(CO)(11) (3)] were prepared. Compound 3 was characterized spectroscopically and an X-ray crystal structure was obtained. The reductive electrochemistry of 1 and 2 showed an irreversible reduction and a follow-up oxidation, similar to Ru-3(CO)(12). The electrochemistry of compound 3 showed two irreversible waves and a follow-up oxidation. A trend in the reduction potential vs. the number of coordinated phosphorus atoms was noted. The oxidative electrochemistry of 1-3 showed a dppf-based chemically reversible wave, and an irreversible wave similar to that of Ru-3(CO)(12). Trends were also noted between the oxidation potential and the number of coordinated phosphorus atoms. (C) 2003 Elsevier B.V. All rights reserved.