Multiply trimethylstannyl substituted ferrocenes synthesis, NMR studies, X-ray structural analysis and electrochemistry

The preparation of the novel compounds 1,3-bis(trimethylstannyl)ferrocene 2, 1,2,4-tris(trimethylstannyl)ferrocene 3, 1,1′,3,3′-tetrakis(trimethylstannyl)ferrocene 5 and 1,1′,2,2′,4,4′-hexakis(trimethylstannyl)ferrocene 6 is described. These ferrocenes as well as (trimethylstannyl)ferrocene 1 and 1,1′-bis(trimethylstannyl)ferrocene 4 have been studied by 1H-, 13C- and 119Sn-NMR spectroscopy. For ferrocenes 5 and 6, the activation energy ΔG# for the hindered rotation of the cyclopentadienyl rings has been determined by variable temperature 1H-, 13C- and 119Sn-NMR spectroscopic studies. The molecular structures of 2, 3, 5 and 6 and the electrochemical properties of 1–6 have been investigated. Steric and electronic effects of the trimethylstannyl groups are discussed on the basis of structural and electrochemical data. The observed redox processes are compared with those in multiply silylated ferrocenes.