Electrochemical and Fluorescent Properties of Ferrocenyl Chalcones Containing 1-Naphthalenyl Group: X-ray Crystal Structure of Fc-C(O)CH=CH-(1-Naph)

Ferrocenyl chalcones (Fc-C(O)CH=CH-Ar: Fe-Ar) with mono- and di-1-naphthalenyl moieties (Fc-1Naph and Fc-d1Naph) were prepared and spectroscopically characterized. The enone bridge was in the s-cis conformation and the pi-electrons on the C=C bond were further delocalized on the bridge. The naphthalenyl moiety deviates greatly from the enone-Cp plane by 26.9(1)degrees. Cyclic voltammetry measurements for Fc-1Naph exhibit one reversible cycle for the redox of the ferrocenyl moiety at a lower potential, and one irreversible oxidation peak at the higher potential region. For Fc-d1Naph, the cyclic voltammogram is more featureless. Fluorescence properties for both compounds are active in polar solvents with lambda(em) = 500 nm (FtOH) and 512 nm (MeOH) for Fc-1Naph and lambda(em) = 496 nm (EtOH) and lambda(em) = 508 nm (MeOH) for Fc-d1Naph. The intensity of Fc-d1Naph is more than twice than that of Fc-1Naph. The fluorescence properties for both compounds are inactive in the less polar solvents such as CH3CN, CH2Cl2 and CHCl3.