Ferrocenyl chalcones containing anthracenyl group: Synthesis, X-ray crystal structures and electrochemical properties

Two ferrocenyl chalcones containing the anthracenyl group, Fc–COCHCH–Anth (Fc–Anth) and Anth–COCHCH–Fc (Anth–Fc), were prepared by solvent-free aldol condensation using acetylferrocene/9-anthraldehyde and 9-acetylanthracene/ferrocenecarboxaldehyde, respectively. The X-ray crystal structure analyses showed that these products crystallize as racemic mixtures. High torsion angles between the anthracenyl group and the enone linkage were observed for Fc–Anth (55.7(4)°) and Anth–Fc (74.9(4)°) and the enone linkage has different conformations for Fc–Anth (s-cis) and Anth–Fc (s-trans). The cyclic and differential pulse voltammetry analyses showed one reversible cycle corresponding to the Fc/Fc+ process (E1/2 = 0.402 V for Fc–Anth and 0.277 V for Anth–Fc), and one irreversible peak corresponding to the oxidation of the anthracenyl group (Epa2 = 1.073 V for Fc–Anth and 1.153 V for Anth–Fc). The fluorescence properties of the anthracenyl group were quenched in these chalcones, possibly by the ferrocenyl group.

Graphical abstractTwo ferrocenyl chalcones with the anthracenyl group were synthesized by base-catalyzed solvent-free aldol condensation and analyzed by 1H NMR and X-ray structure determinations. Their electrochemical properties were investigated by cyclic voltammetry and differential pulse voltammetry measurements, and compared to each other. Their fluorescent properties were also measured at room temperature.Figure optionsDownload full-size imageDownload as PowerPoint slide