Electronic Coupling in Triferrocenylpnictogens

From a fundamental perspective, studies of novel mixed-valent complexes containing ferrocenyl units are motivated by the prospect of improving and extending electron transfer models and theories. Here, the series of triferrocenylpnictogens Fc₃E was extended to the heavier analogues (E = As, Sb, and Bi), and the influence of the bridging atom was investigated with Fc₃P as a reference. Electrochemical studies elucidate the effect of electrostatic contribution on the large redox splitting (ΔE₁) exhibited by the compounds and solvent stabilization in the case of Fc₃As. Structural characterization of the triferrocenylpnictogens combined with spectroelectrochemical studies indicates weak electronic couplings in the related cations [Fc₃E]⁺, suggesting a through-space mechanism.