Oligonuclear Amide‐bridged Ferrocenes from N‐Fmoc Protected 1‐Amino‐1′‐fluorocarbonyl Ferrocene

Abstract

AbstractOligoamides with ferrocenes in the backbone were prepared by stepwise coupling techniques using ferrocenoyl fluorides. The key building block is N‐Fmoc protected 1‐amino‐1′‐fluorocarbonyl ferrocene FmocNH–fn–COF (5). Stepwise coupling of 5 with amino ferrocene Fc–NH2 and (after deprotection) ferrocene carboxylic acid fluoride Fc–COF or 1‐(acetylamino)‐ferrocene‐1′‐carboxylic acid fluoride CH3C(O)NH–fc–COF yielded the dinuclear ferrocene Fc–NHC(O)–fn–NHFmoc (6) and the trinuclear ferrocenes Fc–NHC(O)–fn–NHC(O)–Fc (8) and Fc–NHC(O)–fn–NHC(O)–fn–NHC(O)CH3 (11), respectively. In solution 6 prefers a conformation with an intramolecular hydrogen bond while in the solid state intermolecular hydrogen bonds prevail. The electronic interaction of the ferrocene units in bi‐ and trinuclear ferrocenes with amide linkers has been assessed by electrochemical studies.