Structural Characterization of Chirality‐Organized Ferrocene–Dipeptide Conjugates that Contain Pyridine N ‐Oxide Moieties

Two ferrocene–dipeptide conjugates, Fc( l ‐Ala− l ‐Pro−PyO) 2 ( 2 ) and Fc( l ‐Ala− l ‐Pro−PyO) 1 ( 3 ), were synthesized by the introduction of an l ‐Ala− l ‐Pro dipeptide that contained a C‐terminal pyridine N ‐oxide moiety into the ferrocene organometallic scaffold. Single‐crystal X‐ray structure determination of ferrocene–dipeptide conjugate 2 , which was composed of two dipeptide chains, confirmed the formation of intramolecular antiparallel β‐sheet‐like hydrogen bonds between the CO (Ala) and NH (Ala of another chain) groups to induce a chirality‐organized structure in which the ferrocenoyl moiety adopted a P ‐helical chirality. In the crystal packing of compound 2 , the peptide chains adopted a right‐handed molecular arrangement through hydrogen‐bonding interactions. On the contrary, ferrocene–dipeptide conjugate 3 , which was composed of only one dipeptide chain, self‐assembled into a tetramer structure through the formation of intermolecular hydrogen bonds and π–π interactions between pyridine N ‐oxide moieties.