A spectroscopic, electrochemical and DFT study of para-substituted ferrocene-containing chalcone derivatives: Structure of FcCOCHCH(p-tBuC6H4)

A comparative investigation of seven ferrocene-containing chalcones (Fc-CO-CH=CH-C6H4R, with R = OCH3, CH3, Ph, Bu-t, H, Br and CF3) has been performed based on their electrochemical and spectroscopical behavior as well as with DFT calculations. These compounds were prepared by Claisen-Schmidt condensation of acetylferrocene and the appropriate benzaldehyde derivative. All compounds exhibited reversible chemical and electrochemical behavior, as confirmed by Delta E = 83 - 93 mV and i(pc)/i(pa) = 0.93 - 1.00. The formal reduction potential E degrees' for the compounds ranged between 231.0 and 261.5 mV versus FcH/FcH(+) as an internal standard. The UV-Vis spectra of all ferrocene-containing chalcones showed the characteristic peaks for aromatic systems at +/- 380 nm and a peak in the visible region at +/- 490 nm, which is attributed to the ferrocene moiety. FTIR of all the ferrocene-containing chalcones showed a characteristic CO stretching peak at +/- 1650 cm(-1). DFT calculated HOMO energies and ionization potentials correlate well with experimentally measured E degrees' values. (C) 2011 Elsevier Ltd. All rights reserved.