Electrochemical and NMR spectroscopic studies of selenium- and tellurium-substituted ferrocenes II: Diferrocenyl chalcogenides, Fc2E, diferrocenyl dichalcogenides, Fc2E2, and bis(ferrocenylchalcogeno)alkanes, FcE(CH2)nE′Fc (E, E′=Se: n=1, 2, 3; E, E′=Te: n=1, 3; E=Se, E′=Te: n=3; Fc=[Fe(η5-C5H5)(η5-C5H4)])

1,3-Bis(ferrocenylchalcogeno)propanes, FcE(CH2)3E′Fc (E, E′ = Se, Te), and 1,2-bis(ferrocenylseleno)ethane, FcSe(CH2)2SeFc have been prepared, characterised, and included in a spectroscopic and electrochemical study of a series of compounds containing two ferrocenes linked by a chalcogen-containing bridge. Cyclic and differential pulse voltammetry show that there is electronic communication between the two ferrocene units when the bridge is short (as in Fc2E), but that the interaction rapidly becomes weaker with increasing Fe⋯Fe distance, and is undetectable for the ethane and propane derivatives. 77Se and 125Te NMR spectroscopic measurements reveal that the 77Se chemical shift of Fc2Se2 is anomalously high, which correlates with the long wavelength of its lowest energy electronic absorption.