Mixed-valent ferrocenyltellurenyl halides. Synthesis, electrochemistry and unusual molecular structure

Halogenation of diferrocenyl-ditelluride allows only corresponding mixed-valent ferrocenyltellurenyl-dihalides FcTe-TeX2Fc (X = Cl, Br, I). 125Te NMR and electrochemical data of FcTe-TeI2Fc suggests the monomeric [FcTeI] structure in the solution. In FcTe-TeX2Fc non-halogenated atom of Te is tilted towards the Fe atom so that C-Te bond forms 15°-20° angle with Cp-ring plane.