Inorganic Chemistry, Vol.58, No.6, 3789-3799, 2019
Carbon-Rich Trinuclear Octamethylferrocenophanes
Several trinuclear ferrocenes are obtained by Friedel-Crafts reaction of octamethylferrocene with ferrocenoyl chloride and subsequent modifications. 1,1'-Diferrocenoyloctamethylferrocene (3) is transformed to the divinyl derivative (4a) by reaction with MeLi and AIC13. The reactive 4a cyclizes spontaneously to a [4]ferrocenophane with buta-1,3-diene handle (5) or in the presence of A1C13 to a [3]ferrocenophane with propene handle (6). Structure assignments are supported by X-ray crystallography and NMR spectroscopy, and mechanisms are proposed. Electrochemical behavior of the compounds was investigated with cyclic voltammetry, and assignments of the redox processes were carried out with the aid of density functional theory calculations. The synthesized compounds and demonstrated transformations represent useful tools for preparation of materials for charge-transport studies in metal molecule metal junctions.