Self-assembled structures of ferrocene-l-carnosine conjugates

Abstract

Ferrocene-l-carnosine conjugates, Fc-l-Carnosine-OEt and Fc2-l-Carnosine-OEt, were synthesized and characterized by X-ray crystallographic analyses. The single-crystal X-ray structure determination of Fc-l-Carnosine-OEt was demonstrated to reveal the formation of antiparallel β-sheet-like 12-membered intermolecularly hydrogen-bonded ring between NH (β-alanine) and CO (β-alanine of another molecule). Furthermore, the self-assembled structure through antiparallel β-sheet-like hydrogen bonding network of β-alanyl moieties and homomeric association of the imidazole moieties through the one-dimensional hydrogen-bonded chain was formed in the crystal packing. The self-assembled structure based on antiparallel β-sheet-like hydrogen bonding between NH (histidine) and CO (the ferrocenoyl moiety of another molecule) was also observed in the crystal packing of Fc2-l-Carnosine-OEt. In the case of Fc2-l-Carnosine-OEt, which has the N-ferrocenoyl imidazole moiety, each molecule is connected through the intermolecular hydrogen bonds of CH⋯N pattern between the ferrocene and the imidazole moieties.