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

Two ferrocenyl chalcones containing the anthracenyl group, Fc-COCH=CH-Anth (Fc-Anth) and Anth-COCH=CH-Fc (Anth-Fe), 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)degrees) and Anth-Fc (74.9(4)degrees) 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 (E-1/2 = 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 (E-pa(2) = 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. (c) 2007 Elsevier Ltd. All rights reserved.