Asymmetrically substituted ferrocene derivatives showing redox switching of optical properties

The electrochemical and spectroelectrochemical behaviors of three ferrocene derivatives, (1) (C18H37)(2)N-C6H4-CH=CH-Fc-CH2-OH, (2) (C18H37)(2)N-C6H4- CH=CH-Fc-CHO, (3) (C18H37)(2)N-C6H4-CH=CH-Fc-CH=C(CN)(2) were studied and a nalyzed on basis of frontier orbital interactions. It was shown that all th e three derivatives show two oxidation steps. The first oxidized states of 1 and 2 are stable and show strong LMCT (ligand-to-metal charge transfer) b ands. This suggests that they may serve as redox switching of optical prope rties. In contrast, the first oxidized state of 3 becomes unstable due to s trong electron-withdrawing effect of the acceptor substitute. (C) 1998 Else vier Science Limited. All rights reserved.