Electrochemical and NMR spectroscopic studies of selenium- and tellurium-substituted ferrocenes I: ferrocenyl alkyl chalcogenides [Fe(eta-C5H5)(eta-C5H4ER)]

A series of 22 ferrocenyl alkyl selenides and tellurides has been prepared from the diferrocenyl dichalcogenides. The compounds have been characterise d by mass spectrometry, multinuclear NMR spectroscopy, cyclic and different ial pulse voltammetry. There is a close correlation between the Se-77 and T e-125 chemical shifts of analogous compounds, with delta(Te-125)/delta(Se-7 7)= 1.60. Other trends in the NMR data are also apparent. All the compounds studied undergo a one electron reversible oxidation at slightly more posit ive potentials than ferrocene itself. In addition, the tellurides exhibit a second quasi-reversible process at higher potentials, which appears to be chalcogen-based. There is no obvious correlation between the electrochemica l results and the NMR spectroscopic data. (C) 2001 Elsevier Science B.V. Al l rights reserved.