Tricyanated Ferrocenes; Isolation, structure, electrochemistry and DFT calculations

1,2,3- Tricyanoferrocene and 1,3-dibromo-2,4,5-tricyanoferrocene have been synthesized via metallation usage of dimethylmalononitrile (DMMN) as cyanating agent. They are the first compounds where three nitrile functions could be introduced into ferrocene sceleton. Further studies on electrophilic cyanation lithiated haloferrocenes [Fe(C5HmX4-mLi)(C5H5)] (X=Cl, Br; m=0–3) show formation complex mixtures cyano-halo-ferrocenes [Fe{C5HmX5-m-n(CN)n}(C5H5)] (m=0–3, n=0–3) most likely induced by “halogen-dance” reactions. The molecular crystal structures [Fe{C5H2(CN)3}(C5H5)] [Fe(C5Cl4CN)(C5H5)] discussed. Cyclic voltametric both tricyanoferrocenes irreversible oxidations at very high potentials (Eonset≈845 mV 945 mV, respectively, vs FcH/FcH+).