Structure of Ferrocenoyl Peptides

The crude Fc-amino acids and Fc-peptides are readily purified by chromatographic methods or by recrystallization. In many cases, this results in crystalline materials of sufficient quality for crystallographic investigations. 

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The redox-active ferrocenoyl moieties are surrounding a central H-bonded peptide core. Fcl is involved in the square helix having a right-handed twist, as observed in most p sheets, and Fc2 is involved in the twisted helix. Both helices have a pitch height of 14A. The square helix and twisted helix have an inner diameter of 3.8 A and 4.1 A, respectively. Although peptide-disulfides often exhibit unusual structural features, a supramolecular assembly as exhibited by Fc-glycylcystamine was never before observed in peptide conjugates. 

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