Synthesis and structure of bis- and tris-ferrocene containing N-methylimide foldamers

The synthesis and conformational analysis of dimer Fc–CO–NMe–CO–Fc (5) and trimer Fc–CO–NMe–CO–Fn–CO–NMe–CO–Fc (6) have been described. It has been shown by means of spectroscopic studies, X-ray crystallography, and molecular modeling, that these molecules are dominated by cis–cis conformation. Furthermore, we recognized for the first time, that such type of organometallics possess elements of chiral helicity. Their crystal lattices are characterized by π–π and CH–π intermolecular interactions (5) and by CH⋯Odouble bond; length as m-dashC intermolecular hydrogen bonds (6). We believe that foldamers 5/6 are stabilized by the special type of aromatic π–π interactions between the closer cyclopentadienyl rings of the juxtaposed ferrocene units.