A highly ordered ferrocene system regulated by podand peptide chains

The ferrocene bearing the podand dipeptide chains, Ala-Pro-OEt, which are aligned parallel in solution by the two rigid intramolecular hydrogen bonds, manifests a novel helically ordered arrangement with one turn of 14.70 Å pitch height in the crystal packing possibly due to the intramolecular hydrogen bonds (the N–H···OC distance is 2.06 Å) and the hydrophobic interaction of the podand dipeptide chains (the distance between the nearest ferrocene units is 4.54 Å).